In high–strength concrete, the reinforcement concentration will cause some problems in the beam–column joints (BCJs) due to a large amount of transverse reinforcement. Hence, the main object of this paper is to prevent the reinforcement concentration and reduce the amount of transverse reinforcement in the BCJs through the ideal usage of steel fibers and reinforced high–strength concrete. Pseudo–static tests on seven specimens were carried out to investigate and evaluate the seismic performance of beam–column joints in steel fiber reinforced high–strength concrete (SFRHC). Test variables were steel fiber volume ratio, concrete strength, the stirrup ratio in the core area, and an axial compression ratio of the column end. During the test, the hysteresis curves and failure mode were recorded. The seismic indicators, such as energy dissipation, ductility, strength, and stiffness degradation, were determined. The experimental results indicated that the failure modes of SFRHC beam–column joints mainly included the core area failure and the beam end bending failure. With the increase in stirrup ratio, volume ratio of steel fiber, and axial compression ratio in the core area, both the ductility and energy consumption of beam–column joints increased, while the opposite was true for concrete strength. Under the earthquake load, the beam–column joints (BCJs) of frame structures are prone to brittle shear failure due to the comprehensive action of compression, bending, and shear. As the BCJs are the key part of the frame structure, their failure will easily lead to the collapse of the whole structure. Both Chinese and American seismic codes ,2,3 put In different designs ,10,11,12However, the SFRC test with insufficient steel fiber content shows that the increase in tensile strength is negligible, while the improvement of properties after cracking is limited . TherefoThe related research indicated that the previous studies mainly focused on the seismic performance of steel fiber reinforced concrete (SFRC), with a small part involving the overall seismic performance of SFRHC, and even less local steel fiber–reinforced high–strength concrete. Therefore, the main objective of this study is to investigate the seismic performance of BCJs experimentally by adding a certain volume of steel fibers into the joint core area, adjacent beam end, and column end and reducing the amount of transverse reinforcement in the joint core area. The effects of concrete strength, the axial compression ratio of the column top, volume ratio of steel fiber, and stirrup ratio in the core area of steel fiber reinforced concrete on structural performance are studied. The research aims to improve the seismic performance of SFRHC beam–column joints, including ductility, energy absorption capacity, strength, and stiffness degradation.fl/fd = 35 mm/0.55 mm = 64. The nominal yield tensile strength of the fibers was 1345 MPa. The test specimens were labeled using nomenclatures such as the specimen type and specimen number. For example, the label “BCJ1” defines the specimens as follows: the first three letters indicate the specimen type, where the prefix letter “BCJ” refers to the beam–column joints in the seam joints of steel fiber–reinforced high–strength concrete (SFRHC) beams and columns, and the following digit, “1” is the specimen number. The beam–column joints between the middle column of the plane frame and the inverted beam point were selected as the research object. In terms of SFRHC specimens, BCJ1 was the control specimen, and the others were constructed with representative characteristics. Specimen BCJ0 was cast using normal concrete for comparison. The more detailed information for all specimens is listed in In this paper, a total of seven 1/2 scale beam–column joints were designed and tested, and the effects of concrete strength, the volume ratio of steel fiber, the axial compression ratio of the column end, and stirrup ratio in the core area were considered. The concrete mixture used was composed of ordinary Portland cement, water, well–graded natural river sand, and crushed stone aggregate. The steel fibers added to the fibrous concrete mixture are hook–ended fibers to enhance the anchoring of the fibers in the matrix. The length–to–diameter ratio of the fiber used is equal to 2 with a total height of 1600 mm, and the transverse beam has a cross–section of 150 × 250 mm2 with a total length of 2600 mm. The longitudinal reinforcements in the columns consisted of four B22 bars (a diameter of 16 mm and the grade HRB335 steel), and those for beams consisted of four B16 bars. Transverse reinforcements in columns, beams, and joint core area consisted of an 8 mm–diameter reinforcement. The detailed dimension of the specimens is shown in The schematic of the experimental setup and boundary conditions of experimental specimens are shown in In order to obtain a deeper understanding of the difference in seismic behavior between conventional and SFRHC joints, the failure modes, hysteretic curve, ductility, and energy dissipation capacity, strength and stiffness degradation were discussed and clarified in detail in this section.y, the cracks at the end of the beam widened, and new cracks began to appear, but the core area of the BCJs did not crack. When 2∆y loading, the initial oblique cracks appeared in the core area of BCJs specimens, with a crack width of 0.01 mm and a maximum crack width of 0.6 mm at the beam end. During the 3–4 loading process, the cracks in the core area of BCJs developed slowly, with two small parallel inclined cracks, while the cracks at the beam end developed rapidly, and many new cracks appeared. After 5∆y loading, the bearing capacity of BCJs decreases, many cracks at the beam end run through the section, and cracks in the core area of BCJs develop slowly. After 6∆y loading, the bearing capacity of BCJs decreased to 85% of the peak value, and the test ended. The maximum width of cracks at the beam end was 2.6 mm. There were many parallel inclined cracks in the core area of BCJs, which did not penetrate through the core area. The maximum width of cracks was 0.3 mm. See As shown in As shown in The axial compression ratio of column end on cracks in BCJs is mainly reflected in the cracks in the core area. Initially, inclined cracks appeared in the core area of the BCJ4 specimen with an axial compression ratio of 0.2 at the column end when the load was controlled to 23 kN. The initially inclined cracks appeared in the core area of the BCJ6 specimen with an axial compression ratio of 0.4 at the column end when subjected to cyclic loading twice the yield displacement amplitude. The number of cracks was small during failure, and the cross prominent inclined cracks extended into the column end. Compared to the BCJ1 specimen with a concrete strength of CF60, the initial cracks in the core area of the BCJ3 specimen with a CF80 strength grade appeared later, and the number of cracks was very limited, the oblique cracks were not penetrated, and the width of cracks at the beam end was more petite.Hysteric curves from the beam end corresponding to each specimen were shown in the previous subsection, and the skeleton curve of each specimen, which is obtained by connecting the peak points of hysteretic curves of each beam–column joint specimen, will be given in The effect of volume ratios of steel fiberThe effect of concrete strengths:The effect of stirrup ratios in the core area:The effect of axial compression ratios:μ, which is an important characteristic reflecting the deformability of a structure or specimen. According to the related reference [u is the ultimate displacement when the component load decreased to 85% of the bearing capacity, and ∆y is the yield displacement of the beam end when the specimen yielded. The energy equivalence method [The ductility of a structure or specimen is usually expressed by ductility coefficient eference , the duce method  for deteIt can be seen from eh, is adopted as an index to evaluate the energy dissipation capacity of BCJs specimens. The larger the eh is, the better the energy dissipation capacity of the specimen is. eh defined and is defined by Equation (2) [ABCDA is the area of each hysteresis loop for a complete loading and unloading; SOBE and SODE are the triangular areas corresponding to the maximum load and displacement of the hysteresis loop in the forward and reverse directions. The equivalent viscous damping ratio versus the displacement grade (∆/∆y) of each specimen is provided in Energy dissipation coefficient, work ratio index, and equivalent viscous damping ratio are usually used to quantify the energy dissipation capacity of specimens ,64,65. Ieh increased with the increase in stirrup ratio, the volume ratio of steel fiber, and axial compression ratio in the later loading stage, which indicates that properly increasing stirrup ratio, the volume ratio of steel fiber, and axial compression ratio are helpful to improve the seismic performance of BCJs specimens. Compared to BCJ1 specimen with concrete strength CF60, the equivalent viscous damping ratio of the BCJ5 specimen with concrete strength CF80 increased by 5% before loading to the peak value, while it decreased by 8% at the final failure. It showed that with the increase in concrete strength, the brittleness of concrete increases, and the energy consumption decreases in the failure stage. The results also showed that the equivalent viscous damping ratios of SFRHC joints BCJ1–BCJ6 were between 0.136 and 0.201, the BCJ0 specimen without steel fiber was 0.085, indicating that SFRHC beam–column joints had a better seismic performance. The difference of equivalent viscous damping ratio among all the specimens was very small when longitudinal yielding was not yielding in the initial loading stage. Concrete strength, the axial compression ratio of column end, stirrup ratio, and volume ratio of steel fiber have almost no influence on the energy dissipation capacity of BCJs specimens. After longitudinal yielding, iλ), which reflects the degree of strength reduction with the increasing cyclic number under the same displacement condition [iλ is defined in Equation (3):iPj, represents the peak load value when the displacement grade is i (I = Δ/Δy); i,P1 represents the first cycle peak load value when the displacement grade is i (I = Δ/Δy). Pi,j and i,P1 take the average value of peak load under forward and reverse loading. The relationship curve between the strength degradation coefficient and the displacement grade of each specimen is shown in The strength degradation characteristic is typically expressed by the strength degradation coefficient (ondition . λi is dAs shown in ik) is defined as follows [Pi,j represents the peak load value when the displacement grade is i (i = ∆/∆y), and the unit is kN; ∆i,j represents the peak displacement value when the displacement grade is i (i = ∆/∆y), and the unit is mm; n represents the number of cycles. Under the condition of constant displacement, the stiffness of the joint decreases with the increase in cycle times. Stiffness degradation can be measured by the ring stiffness. By analyzing the ring stiffness, the stability and energy dissipation capacity of the hysteretic curve of the joint can be further clarified. The stiffness degradation coefficient ( follows :(4)ki=∑jWith the increase in displacement, the effective stiffness of the specimens decreased. The decrease in specimen stiffness is usually attributed to joint zone distortion, shear cracking, flexural loss of concrete coating, the slip of reinforcement, and nonlinear deformation of concrete. As shown in With the change in axial compression ratio of column end, concrete strength, the stirrup ratio in the core area, and volume ratio of steel fiber, two modes of the joint–shear–failure area exist in the core area and beam–end–bending failure;Because of the bridging effect of steel fiber, the initial crack strength and the through crack strength of BCJs can be improved by adding steel fiber into concrete. Moreover, with the increase in volume ratio of steel fiber from 0 to 1%, the ductility and energy consumption of BCJs increase by 45.2% and 120%, respectively, while the degradation of strength and stiffness slows down;With the increase in concrete strength from 80.1 to 89.5 Mpa, the ultimate bearing capacity and energy consumption of beam–column joints increase by 4% and 8%, respectively, while the ductility decreases by 9%.With the increase in stirrup ratio in the core area from 0 to 0.6%, the ductility and energy consumption of beam–column joints increases by 25% and 20%, respectively;The axial compression load has a limited effect on the strength and deformation capacity.This paper presents an experimental investigation on the seismic behavior of SFRHC beam–column joints by conducting seven tests. The effects of concrete strength, the volume ratio of steel fiber, stirrup ratio in the core area, and axial compression ratio of the column end on the seismic performance of the joint are studied. Based on the experimental results, the main conclusions can be drawn, as follow:


Prosthetic joint infection (PJI) is the second most common cause of arthroplasty failure. Though infrequent, it is one of the most devastating complications since it is associated with great personal cost for the patient and a high economic burden for health systems. Due to the high number of patients that will eventually receive a prosthesis, PJI incidence is increasing exponentially. As these infections are provoked by microorganisms, mainly bacteria, and as such can develop a biofilm, which is in turn resistant to both antibiotics and the immune system, prevention is the ideal approach. However, conventional preventative strategies seem to have reached their limit. Novel prevention strategies fall within two broad categories: (1) antibiotic- and (2) heavy metal-based surface modifications of titanium alloy prostheses. This review examines research on the most relevant titanium alloy surface modifications that use antibiotics to locally prevent primary PJI. The use of arthroplasty makes it possible to replace a natural joint with artificial material or a joint prosthesis. Although, arthroplasty is highly effective and has improved the quality of life of millions of patients , implantThe aim of this work is to review research on the most relevant titanium alloy surface modifications that use antibiotics to locally prevent primary PJI.Staphylococcus aureus (30–40%) and different species of coagulase-negative staphylococci (27–43%), among which S. epidermidis predominates, are the most common etiological agents associated with PJI [Enterococcus species, Staphylococcus, and various Gram-negative bacilli such as Enterobacteriaceae and Pseudomonas aeruginosa are often associated with these infections.Staphylococci, including with PJI ,10,11,12with PJI , enterobwith PJI  or the awith PJI ,15. Polywith PJI . EnterocAcinetobacter baumannii, P. aeruginosa, enterobacteria , Enterococcus faecium, S. aureus, Helicobacter pylori, Campylobacter spp., Salmonella spp., Neisseria gonorrhoeae, Streptococcus pneumoniae, Haemophilus influenzae, and Shigella spp. [S. aureus, P. aeruginosa, K. pneumonia, E. cloacae, and E. faecium, and for that, the antibiotic resistance is also an emerging threat for PJI and must be taken into account in the development of any preventive treatment against them.A problem of growing importance associated with bacterial infections is antibiotic resistance . Accordilla spp. ,18. As c(1)Staphylococcus spp. [Attachment. Microorganisms come into contact with the surface, a process that is at least partly stochastic, driven by physical and chemical forces ,26,27. Fcus spp. ,29.(2)Maturation is characterized by intercellular aggregation coupled to a variety of molecules such as proteins or, usually, exopolysaccharides of a polysaccharide nature, and structuring forces that rearrange the biofilm into three-dimensional structures of variable morphology depending on the species and with microchannels within them . During (3)Dispersal. This is the process by which mature biofilm cells disperse to adjacent areas passively or actively ,27. ThroOne of the most important characteristics in all the aspects of PJI is the ability of microorganisms to form biofilms. A biofilm is a conglomerate of microbial cells of at least one species that is irreversibly attached or not on a surface or an interface, and embedded in a self-produced matrix of polymeric extracellular substances , where nThe implications of biofilms in treatment and outcomes are enormous, as they confer phenotypical resistance that required the use of new surgeries and prolonged treatments. It is therefore of utmost importance to avoid bacterial colonization of implants and thus avoid the appearance of infection. Moreover, the possibility of an interaction between biofilms, cells, and implanted biomaterials is also of great importance, as the reservoir in the tissue also needs to be removed to cure patients ,35.Conventional prevention of PJI includes all measures developed for preventing surgical site infections (SSIs) that have appeared in official guidelines and statements ,37. MoreHowever, even taking all those risk factors into account, there are still several patients who develop PJI after surgery. Several strategies have been devised to avoid this kind of infection.During prosthetic implantation, the bone and surrounding tissue must be irrigated; in addition, after implantation, the periprosthetic tissue may be left damaged, avascular, or even, necrotic. These events inherent to surgery locally reduce the concentration of the antibiotic systemically administrated and make it necessary to use a local antibiotic approach with a period of action of hours or days.locus minus resistentiae, which is an immunosuppressed fibro-inflammatory zone [On the other hand, the foreign body reaction after the implantation gives rise to an interstitial milieu or a ory zone . This zoory zone , which iory zone . TherefoThe ideal antibiotic-loaded titanium alloy surface modification would require two components: a titanium alloy component and an antibiotic component. The ideal titanium alloy surface modification must not compromise its good corrosion resistance, high strength, low weight, its Young’s modulus of elasticity , or non-The local prevention approach can be classified into two types according to the mechanism of action: passive and active modifications. Passive modifications are surface coatings that endow biomaterial with antibacterial  properties without releasing any compound that is responsible for these properties. The active modifications do endow biomaterials with antibacterial properties through a compound released from the material. These active modifications are divided into two groups: active surfaces and coatings. The most recent antibiotic-loaded surface modifications of titanium alloys are illustrated in The active titanium surfaces loaded with antibiotics can be divided into two categories: nanostructured surfaces and surfaces with covalently bound antibiotics.The most representative nanostructured titanium surface approaches are summarized in This nanostructure allows its loading using different methods, mainly simplified lyophilization or soaking.Bacterial and cellular adhesion are complex processes arising from the interaction between surface properties, biological factors, and environmental conditions. A recent systematic review concludes that there are three reasons why the relationship between surface topography and bacterial attachment can give rise to contradictory results: (i) roughness cannot be the sole descriptor of surface topography; (ii) topographical effects are influenced by the effects of other physicochemical factors, such as surface chemistry; and (iii) different anti-adherent mechanisms may take place at different topographical scales: nanoscale and microscale . The lasThe nanotube diameter is pivotal for the release profile ; that isAntibiotics covalently bound to titanium surfaces is another type of active titanium surfaces with antibiotics . The maiSome of the most relevant coatings loaded with antibiotics described over the last 10 years are summarized in C. albicans infection both in vitro [Different approaches of deposition of antibiotic-loaded coatings such as sol–gel, covalent immobilization, spraying, electrophoretic, polyelectrolyte, and dip coating have been used on titanium surfaces . Most ofin vitro  and in vin vitro .The most commonly used synthetic polymers are poly (lactic-co-glycolic acid) (PLGA) , poly (ethylene glycol-propylene sulphide), and poly-D,L-lactide. Most have been approved by the Food Drug Administration due to their biodegradability and biocompatibility in light of a vast number of recently reviewed studies ,120. NewThere are two marketed products based on the antibiotic-loaded degradable coating for titanium implants: gentamicin poly  (PLLA) coating, and a fast-resorbable hydrogel coating composed of covalently linked hyaluronan and PLLA. Gentamicin PLLA coating is based on a fully resorbable PLLA matrix loaded with gentamicin sulphate which releases 80% of its antibiotic load within the first 48 h . GentamiFast-resorbable hydrogel coating is composed of covalently linked hyaluronan and PLLA and is marketed as Defensive Antibacterial Coating (DAC) . DAC is the first antimicrobial hydrogel specifically designed to avoid implant-related infections in orthopaedic surgery and trauma, dentistry, and maxillofacial surgery ,129. ItsTrentinaglia et al.  have recThe use of almost any antibiotic in clinical practice is always followed by the development of resistant organisms, and the case of antibiotic-loaded titanium surfaces is not an exception. Antimicrobial resistance is the result of three major factors: (1) the increasing frequency of antimicrobial-resistant phenotypes among microbes resulting from selective pressure exerted by the widespread use of antimicrobials; (2) globalization, which favors the rapid spread of pathogens worldwide; and (3) improper use of antibiotics .S. aureus [S. epidermidis [E. coli and P. aeruginosa. Given the incidence of PJI (up to 40%) [The antibiotic of choice for local antibiotic-based therapy should ideally be a broad-spectrum antibiotic that is the least allergenic possible and with no local adverse effects or cytotoxicity; furthermore, these antibiotics should not interfere with osseointegration or be essential for the treatment of PJI . Most of. aureus  and S. edermidis . Therefodermidis ,108,143. to 40%) , Gram-neThe increasing prevalence of antibiotic resistance among bacteria resulting in the selective pressure which the widespread use of antibiotics exerts on them, the globalization, and the inadequate use of antibiotics in many different settings  threatenMetals have been used by the Persians, Phoenicians, Greeks, Romans, and Egyptians for their antimicrobial properties for thousands of years ,146. Des® . Anodizing gives rise to the formation of 5 μm diameter circular tanks in the surface of the prosthesis, containing an amorphous titania species where the bulk of the ionic silver is stored. Silver galvanic deposition into titanium alloy prostheses is marketed under the name MUTARS® . Its technology consists of a 15 ± 5 μm-thick silver coating deposited by galvanic deposition on a 200 nm layer of gold that acts as a carrier and bonding layer to the prosthesis. Recently, Deng et al. [Regarding the use of these metallic-based titanium alloy surface modifications in patients, it is noteworthy that there are no comparative or prospective studies and only retrospective cases of series have been published. Only silver has been proven in humans and has shown low infection risk in clinical studies. There are two technologies marketed nowadays for incorporated silver into titanium alloys: anodization and galvanic deposition. Titanium alloy prostheses with silver incorporated by anodizing is marketed under the name Aglunag et al.  have poig et al. ,176,177 g et al. ,176,178,g et al. . Second,The use of heavy metals for PJI prevention may just be getting started, thus new promising metallic candidates with antimicrobial capacity are yet to be employed. This is the case for metals such as nickel ,181, cerDespite all the potential benefits offered by local prevention strategies for prosthetic joint infections, each has several limitations associated with its use. The advantages and disadvantages related to each preventive approach of PJI are summarized in Titanium nanotubular surfaces have at least five limitations. Firstly, the low drug concentration resulting from sustained release in a non-bacteria environment consumes antibiotic reserves and increases the possibility of developing drug-resistant bacteria in the vicinity of the implant . TherefoRegarding antibiotics covalently bound to titanium surfaces, there are also important limitations associated with this approach. Unlike nanostructured surface, the antibiotics covalently bound to surfaces are not released into the milieu, and thus can only exert their action on bacteria in direct contact with the modified surface. There is no information about the exact durability of their protection or the hypothetical effect of the release of chemically modified antibiotic on the target bacteria and its role on the emergence of antibiotic resistance. The chemical reaction needed for obtaining these surfaces makes the intra-operative antibiotic load impossible. Finally, there are no clinical trials to back up their use in humans.Antibiotic-loaded coatings also show limitations. The main limitation is the incomplete protection of the implant, since the intramedullary component of the prosthesis and some modular components  cannot be coated. Therefore, an area of susceptibility will exist, where a bacterial infection could proliferate. There is absence of knowledge about the long-term effect that the product resulting from its degradation could exert on the useful life of the implant, its osseointegration, or even, the patient coagulation profile. Although it is the only approach with clinical trials, few antibiotics loaded in such coatings have been used so far.Heavy metals into titanium surfaces are also associated with some limitations. First, the price of these modified implants is high because they are indicated for a very low number of specific patients . Second,Therefore, toxicity is the first concern pertaining to these modifications. With a silver coating, the elevated silver concentration in the blood or in organs has been proven by Gosheger et al. , while tE. coli and P. aeruginosa) [Other limitations include the selection of antimicrobial compound. For preventive use, narrow-spectrum antibiotics that cover most potential pathogens are recommended for chemoprophylaxis ,37. Howeuginosa) ,204, oneuginosa) .In this scenario, the selection of the antimicrobials necessary to prevent PJI infections should consider the existence of multidrug-resistant bacteria , which eResearch into the development of locally antibiotic therapy approaches is broad and varied, though this review could mark the beginning of a promising journey towards the development of prostheses capable of complete PJI prevention. Despite the numerous preclinical studies that have been conducted, such as those using in vivo models, the move from bench to bedside continues to be hindered by at least two factors, including the low incidence of PJIs and the costs of clinical trials needed to demonstrate the efficacy of these approaches in human beings; indeed, these costs are so high that only large pharmaceutical companies can afford such an investment. These factors may be responsible for the fact that existing multicenter prospective clinical trials are poorly well-structured and often show contradictory or inconclusive results . Thus, tOur review highlights that a trend from the antibiotic-loaded surface modifications of the bulk material to the biodegradable antibiotic-load coating can be observed since only two types of these coatings have come to be used in humans. Among heavy metals, silver-modified titanium surfaces are supported by numerous in vitro studies and clinical trials, though other metals such as copper or gallium might stand up as potential future candidates. Furthermore, there is no uniform way of evaluating the efficacy of such approaches. For that, we consider that at least cytotoxicity and cell proliferation should be evaluated in vitro, and that all be tested by using in vivo models. Due to the increasingly threatening emergence of antibiotic resistance, it would therefore be recommendable to use at least two antibiotics or heavy metals for functionalizing the titanium surfaces or antimicrobial substances whose antibacterial mechanisms do not lead to the development of resistant bacterial mutants. Finally, any of the PJI prevention approaches reviewed here are exempt of limitations, many of which should be elucidated by specifically designed studies.


Listeria monocytogenes has been implicated in several ready-to-eat (RTE) foodborne outbreaks, due in part to its ability to survive under refrigerated conditions. Thus, the objective of this study was to evaluate the effects of sodium bisulfate (SBS), sodium lactate (SL), and their combination as short-duration antimicrobial dips (10-s) on L. monocytogenes and the microbiome of inoculated organic frankfurters (8 Log10 CFU/g). Frankfurters were treated with tap water (TW), SBS0.39%, SBS0.78%, SL0.78%, SL1.56%, SBS+SL0.39%, SBS+SL0.78%. In addition, frankfurters were treated with frankfurter solution water (HDW)+SBS0.78%, HDW+SL1.56%, and HDW+SBS+SL0.78%. After treatment, frankfurters were vacuum packaged and stored at 4°C. Bacterial enumeration and 16S rDNA sequencing occurred on d 0, 7, 14, 21. Counts were Log10 transformed and calculated as growth potential from d 0 to d 7, 14, and 21. Data were analyzed in R using mixed-effects model and One-Way ANOVA (by day) with differences separated using Tukey’s HSD at P ≤ 0.05. The 16S rDNA was sequenced on an Illumina MiSeq and analyzed in Qiime2-2018.8 with significance at P ≤ 0.05 and Q ≤ 0.05 for main and pairwise effects. An interaction of treatment and time was observed among the microbiological plate data with all experimental treatments reducing the growth potential of Listeria across time (P < 0.0001). Efficacy of treatments was inconsistent across time; however, on d 21, SBS0.39% treated franks had the lowest growth potential compared to the control. Among diversity metrics, time had no effect on the microbiota (P > 0.05), but treatment did (P < 0.05). Thus, the treatments potentially promoted a stable microbiota across time. Using ANCOM, Listeria was the only significantly different taxa at the genus level . Therefore, the results suggest incorporating SBS over SL as an alternative antimicrobial for the control of L. monocytogenes in organic frankfurters without negatively impacting the microbiota. However, further research using multiple L. monocytogenes strains will need to be utilized in order to determine the scope of SBS use in the production of RTE meat. Listeria monocytogenes, a foodborne pathogen capable of withstanding various stress environments  , SL [0.78% and 1.56% (w/v)] (Alfa Aesar), and the combination  in tap water (TW). Solutions were also made using the hotdog water (HDW) remaining in the package after removing the franks. The HDW was combined to create a bulk homogenate and treatments using HDW  and their combination [HDW + 0.78 SBS+ 0.78 SL] were generated. After treatments were made (k = 11), one replicate of each treatment solution was analyzed for pH with a SympHony pH meter and probe . The pH of SBS (0.39 and 0.78%) and SL (0.78 and 1.56%) prior to constructing combinatory treatments are shown in 10 CFU/mL was spot inoculated onto the surface of the frankfurters in a sterile collection bag. Inoculum levels were confirmed via serial dilution and spread plating on Oxford agar.A total of 176 frankfurters were used per trial , with the experiment being conducted at 3 independent times  for a total of 132 frankfurters per sampling day and 528 frankfurters being used in total during the onset of the current experiment. Recently obtained frankfurters (< 24 h from purchase) with an average weight 47 g per frankfurter were transferred to sterile collection bags . Per frankfurter, 1 mL of the freshly prepared inocula with a confirmed cell density between 8 and 9 LogListeria monocytogenes in foods, the total inoculated Listeria monocytogenes EDG on both the surface and interior of the organic frankfurters, an inoculated, no treatment, control was weighed and subsequently stomached at 200 rpm for 1 min in 100 mL of nBPW [−6, 100 μL of the diluted homogenate was spread plated on Oxford agar in duplicate, and incubated aerobically for 24 hours at 37 °C. The final attachment level was determined to be between 7 and 8 Log10 CFU/g.After the inoculation of the organic frankfurters, each group was stored at 4 °C for 60 min to allow for the attachment of the cells on the surface of the frankfurters. Using modified sample preparation and direct plating methods developed by the USDA-FSIS and FDA for  of nBPW , 28. TheAfter the attachment period, the inoculated frankfurters were submerged in their respective antimicrobial treatments. Treatment applications of the eleven treatments (k = 11) were performed with one frank per treatment, with four replications (n = 4). Frankfurters were transferred to sterile wide-mouthed containers (500 mL capacity) with 20 mL of the respective antimicrobial solutions. Frankfurters were manually agitated for 10 sec, aseptically transferred to sterile collection bags, and allowed to rest for 2 minutes. Afterward, frankfurters were aseptically transferred to vacuum package bags, vacuum-sealed , and stored at 4 °C until bacterial enumeration could be conducted on days 0, 7, 14, and 21.−1 to 10−6, and were enumerated via direct plating methodology where 100 μL of the diluted homogenates were spread plated on Oxford agar in duplicate. Plates were aerobically incubated for 24 hours at 37 °C, with an enumeration range for this experiment being selected at 25 to 250 colonies per plate. Approximately 1 mL of the frankfurter homogenates collected on days 0, 7, 14, and 21 were aliquoted to 1.5 mL microcentrifuge tubes without transferring solid pieces of the frankfurters and stored at -20 °C until DNA extraction could be conducted.On days 0, 7, 14, and 21, treated frankfurters were removed from refrigeration (4 °C) and stomached for 1 min at 200 rpm in 100 mL of nBPW  so that Frankfurter homogenates collected on days 0, 7, 14, and 21 were thawed at room temperature, and the genomic DNA was extracted using the standard spin-column procedure for cultured cells using the QIAGEN DNeasy Blood & Tissue Kit . Extracted samples were eluted in 50 μL of Buffer AE by directly hydrating the spin column and allowed to incubate at room temperature for 10 min. All eluted DNA samples were analyzed using a NanoDrop 1000 Spectrophotometer  to determine the isolated DNA concentration and purity ratios . The extracted DNA was diluted to 10 ng/μL in Buffer AE and stored at -20°C until the library could be prepared.™ Normalization kit . The pooled library contained a 5 μL aliquot of each normalized sample. Concentrations were determined using a KAPA library quantification kit for Illumina platforms  and a Qubit fluorometer . At the same time, product size was assessed using an Agilent 2100 Bioanalyzer System . The library and PhiX Control v3  were diluted to 20 nM in HT1 Buffer and denatured in 0.2 N fresh NaOH to generate a final concentration of 12 pM. The resulting library was combined with PhiX control v3  and loaded onto a MiSeq v2 (500 cycles) reagent cartridge . Subsequent sequences were uploaded to BaseSpace , NCBI Sequence Read Archive (PRJNA732908), and GitHub .A sequencing library was constructed based on the V34, V4, and V45 regions of the 16S rDNA using custom primers designed by Kozich et al. . IndividListeria was first Log10 transformed and reported on a CFU of Listeria per gram of frankfurter basis (CFU/g). Subsequently, the recovered Listeria per gram of frankfurter on d 7, 14, and 21 was subtracted by the initial recovered Listeria per gram of frankfurter on d 0 to represent the growth potential of Listeria per gram of frankfurter on d 7, 14, and 21. The data were analyzed in a mixed effect model with the random effect being trial and the fixed effects being time and treatment in RStudio. Version 1.4.1103 using the lme4, lmerTest, emmeans, and multcomp packages to determine the effect of treatment, day, or potential interaction between the two [Each frankfurter was randomly assigned to treatment prior to the onset of the study. The CFU of  the two –37. To fThe QIIME2 pipeline (version 2020.8) was utilized for sequencing data analyses . DemultiThe solutions of SBS at 0.39 and 78% and SL at 0.78 and 1.56% were the only solutions measured for pH during the onset of the experiment . The pH Listeria monocytogenes EDG-e. Therefore, 0.39% SBS, 0.78% SL, and 0.39% SBS+SL were determined to be the minimum inhibitory concentrations and 0.78% SBS, 1.56% SL, and 0.781% SBS+SL were determined to be the minimal bacteriostatic concentrations that were ultimately used in the current experiment . The growth potential was lowest on d 7 compared to d 21 for most treatments; except those treated with SBS at 0.39% and HDW . On d 7, the growth potential of Listeria from those treated with 1.56% SL was the lowest (-0.009 Log10 CFU/g), but by d 14 and 21 the growth potential of those frankfurters had increased to 0.0.628 and 0.569 Log10 CFU/g and did not have the lowest growth potential among treated frankfurters. In fact, on d 21, frankfurters treated with SBS 0.39% had the least numerical growth potential (0.361 Log10 CFU/g). The growth potential of those treated with SBS 0.39% on d 21 were not different than those treated with SBS 0.78% but were different than all other treatments on d 21. Overall, there was no change in the growth potential of Listeria of those treated with 0.39 and 0.78% of SBS from d 0 to d 21. Due to the complexity of the analysis, further analyses were performed to separate means by day to delineate day by day efficacy of treatments on the growth potential of Listeria.Initially, a mixed effect model was utilized to determine the main effect of treatment and time and their subsequent interaction on the growth potential of Listeria . In the Listeria on d 7, 14, and 21, independently. On d 7, only those treated with SL at 1.56% (-0.009 Log10 CFU/g) had a significantly lower growth potential compared to the no treatment control and those treated with tap water  were the lowest compared to all other treatments even though they were not different to those treated with SBS 0.78%, SL 1.56%, SBS + SL 0.39%, and HDW + SBS + SL 0.78%.The effect of treatment was separated by day to delineate the effect of treatments on the growth potential of Listeria compared to the no treatment control and TW treated franks . The growth potential of those treated with SBS 0.39% was different than the no treatment controls and those treated with water, SL 0.78%, SBS + SL 0.78%, HDW + SBS 0.78%, and HDW + SL 1.56. Additionally, the growth potential of those treated with SL 0.78% and HDW + SL 1.56% was not different than that of those treated with HDW + SBS + SL 0.78% and SBS + SL 0.78%.On d 21, all experimentally treated franks had less growth potential of Using ANOVA, the main effects and interactions were explored for α-diversity metrics on the indigenous frankfurter microbiota. The main effect of treatment was only significant for Shannon’s diversity (P = 0.029), and there was no main effect of time or interaction of treatment × time for any of the other α-diversity metrics . The onlWhen using ADONIS, a non-parametric multivariate analysis of variance, there were no interactions between treatment and time on any of the β-diversity metrics , Fig 6. Listeria monocytogenes, mean taxa bar plots were generated. In addition, ANCOM was utilized to determine the significantly different abundant taxa among the microbiota at the phylum and genus levels , Bacillaceae (family), Bacillus, Lactobacillus, Leuconostoc, Listeria, Pseudomonas .To look at the overall microbial composition of frankfurters inoculated with els Figs –9. The tudomonas . Among tListeria monocytogenes EDG-e and the impact of the microbiota of organic frankfurters during a 3-week shelf-life. Organic, no additives frankfurters were obtained from a local supermarket, confirmed Listeria-free, and artificially inoculated with L. monocytogenes EDG-e. There were 11 different short-antimicrobial dip treatments comprised of SBS and SL alone or in various combinations with tap water (TW) and hot dog water (HDW). Throughout the study (21-d), experimental short-antimicrobial dip treatments reduced L. monocytogenes EDG-e populations compared to the control groups, the no treatment control and TW. Although only L. monocytogenes EDG-e was utilized during this shelf-life study, this does provide potential insight into the use of these antimicrobials as short duration dips instead of being directly incorporated into the frankfurter batter as many antimicrobials have been added in the past.As consumer education and awareness of chemical and synthetic additives increases, the demand for “healthier” alternative food products is also increasing . This phThe pH of both SBS and SL solutions were taken to determine how acidic these products were in solution. The pH of the SBS (0.39 and 0.78%) solutions was below 2; whereas the pH of SL (0.78 and 1.56%) solutions was close to neutral with a pH between 6.5 and 7.5. Although the pH of the solutions for the combinations was not taken, it can be noted that the pH of SBS was much lower than that of SL. Tthe pH of the SL solutions was 7.37 and 6.83 . However, as there was minimal replication of the pH of the solutions and they were not statistically analyzed, nothing can be concluded.The use of tap water in the current study was utilized as a control in addition to the no treatment control. There was no pre-treatment of the tap water in terms of sterilization as the tap water was directly obtained from the water supply at the Center for Food Safety at the University of Arkansas. The water supply at the University of Arkansas is derived from the Beaver Water District  that is distributed to multiple cities and municipalities in Northwest Arkansas. According to the 2020 water quality report at the City of Fayetteville Arkansas which distributed the Beaver Water supply to the University of Arkansas, there is less than 1 ppm of chlorine, fluoride, nitrates, and less than 0.01 ppm of lead and copper . Therefo10 CFU/g [10 CFU/g reduction of Listeria when frankfurters were treated with tap water compared to those designated as the no treatment control. This reduction was sustained over a 21-d shelf-life and is in agreement with previous research. Thus, there is a potential rinsing effect of tap water when used as a 10-s dip prior to packaging.It has been well established in other food matrices such as poultry that there is a rinsing effect of water on the loosely attached microorganisms on the surface of the product –63. In t10 CFU/g –63. In tListeria monocytogenes can occur anywhere during processing due to the potential for reintroduction. However, current lethality steps such as cooking or smoking should eliminate microorganisms on or within the RTE product [Listeria monocytogenes can often be located on the surface and in the exudate of RTE products [It is well established that the contamination of frankfurters and other RTE meats with  product . The re- product . As the products , 66.L. monocytogenes EDG-e on the frankfurters. The results indicated that on d 7 the growth potential of L. monocytogenes EDG-e on the frankfurters treated with HDW with either the addition of SBS or SL or their combination were not different from one another, nor the controls used in the current study, the no treatment control and tap water. On d 14 and 21, the L. monocytogenes EDG-e growth potential in frankfurters treated with HDW with either the addition of SBS, SL, or their combination were different than the controls and the growth potential of L. monocytogenes EDG-e of those treated with the combination of HDW, SBS, and SL (0.78%) and those treated with SBS (0.39%), the treatment with the lowest growth potential, were not different on these days. Neither the treatment of frankfurters with HDW + SBS (0.78%) or HDW + SL (0.78%) resulted in similar growth potentials to that of HDW + SBS (0.78%) + SL (0.78%) and SBS (0.39%). Therefore, the combined addition of SBS and SL in the frankfurter exudate may provide an additional intervention strategy to use in a multi-hurdle approach to reduce the Listeria monocytogenes levels among RTE meats comparative to that of using SBS (0.39%) alone. Further research incorporating these antimicrobials in the interior of the RTE packaging would need to be explored in order to fully assess the robustness of this application.Therefore, in the current study, SBS, SL, and their combination were added to a bulk homogenate of the exudate from the frankfurters (HDW) used throughout the study. The specific aim was to see if these chemical interventions could reduce the surface contamination of L. monocytogenes and other potential foodborne pathogens. As such on d 21, the treatment of frankfurters with 0.39% SBS as a short duration antimicrobial dip resulted in only a 0.361 Log10 CFU/g growth potential of L. monocytogenes from d 0 and almost a 4 Log10 CFU/g reduction of Listeria compared to the controls at that time. Interestingly, the use of 0.39% SBS (0.552 and 0.361 Log10 CFU/g) as a short duration antimicrobial dip on L. monocytogenes EDG-e inoculated frankfurters resulted in numerically greater mitigation of growth potential over a 21-d refrigeration period compared to the higher SBS solution, 0.78%, on d 14 and 21 (0.685 and 0.485 Log10 CFU/g). However, there were no statistical differences between the two concentrations throughout the study. Therefore, it would be more cost effective for industry personnel to use the lower SBS concentration of 0.39% without losing antimicrobial potency.In the current study, the authors examined the addition of SBS to short duration antimicrobial dips post-cooking prior to packaging to mitigate L. monocytogenes on artificially contaminated Granny Smith apples (106 Log10 CFU/g) by 2 and 5 Log10 CFU/g over a 14 day period. More recently, Bodie et al. [L. monocytogenes on organic beef frankfurters with the use of 0.75 and 1.5% SBS achieving over a 2 Log10 CFU/g reduction of inoculated frankfurters immediately after treatment. In addition, SBS has been reported to be an effective antimicrobial agent against Salmonella spp. in multiple environments such as poultry parts, rendered chicken fat, and poultry reuse water [Although, there is limited information on the use of SBS as an antimicrobial ingredient or short duration antimicrobial dip on frankfurters, this does conform with previous research involving SBS used as a short duration dip. Kim et al.  demonstre et al.  demonstrse water –18. Lastse water , a saferse water , is not L. monocytogenes population had a growth potential of 0.756 Log10 CFU/g at 21 days post inoculation which was significantly less than that of those designated as the no treatment control or those treated with TW (10 CFU/g increase in L. monocytogenes (V7) after 21 days at 4 °C. Conversely, Glass et al. [Listeria growth by only 0.16 CFU/ per package after 30 days. It is suspected that the addition of SL into frankfurters formulation can provide a bacteriostatic effect.Sodium lactate is a frequent food additive to meat and poultry products as a flavor enhancer as its use in organic RTE meat is approved by the USDA and National Organic Standards Board . In the  with TW . Lungu as et al.  found thL. monocytogenes in cured meat and poultry products [Listeria on artificially inoculated frankfurters when used as antimicrobial rinses. However, in the current study, there was no additive effect of SBS and SL in combination at any concentration implying that there is not a synergistic benefit from the inclusion of both SBS and SL in a 10-s dip. Additionally, the increase in concentration from 0.39% to 0.78% of both SBS and SL when in combination did not improve the efficacy of this short duration dip in mitigating L. monocytogenes EDG-e growth in frankfurters. The increase in concentration from 0.39% to 0.78% of both SBS and SL when in combination resulted in numerically higher growth potential throughout the study, similar to what was seen with the increase in concentration from 0.39% to 0.78% of SBS used alone. Therefore, there was no additive effect of increasing the concentration of SBS past 0.39% on frankfurters inoculated with L. monocytogenes EDG-e. Potentially, when SBS is applied to frankfurters as a 10-s rinse, a plateau in antimicrobial efficacy is reached between 0.39% and 0.78% but further studies would need to confirm this in the contexts of SBS applied as short duration dips on frankfurters inoculated with L. monocytogenes EDG-e.Currently, there is a need for alternative antimicrobials for food safety interventions in organic products in the RTE meat industry. In the meat industry, SL and sodium diacetate are commonly used antimicrobials to create a synergistic effect on meat products. Several studies have verified that the addition of SL and sodium diacetate combinations to the formulation of food products creates a synergistic inhibition of products . Howeverproducts , 73. TheL. monocytogenes population illustrates the antimicrobial with the greatest efficacy. Throughout the study, depending on the day, the antimicrobial effect was not consistent across treatments with frankfurters. However, those treated with SL 1.56%, SBS 0.39%, and SBS 0.39% had the least growth potential of L. monocytogenes on d 7, 14, and 21, respectively. As such, the various antimicrobial treatments demonstrated different peaks in performance at the different time points, leading to the variation observed when assessing the most effective treatment per day. These results indicate that SBS and SL exhibited an anti-listerial effect on organic frankfurters from day 0 to day 21, with SBS exhibiting a greater impact on the reduction of Listeria as shown by d 14 and 21 pairwise comparisons.Ultimately, the treatment with the lowest recovery of L. monocytogenes EDG-e in the current study, this study was designed to determine the shift of the microbiota of artificially contaminated frankfurters in response to the aforementioned antimicrobial treatments over a 21-d shelf life. To date, there is limited knowledge identifying the microbial communities established on organic RTE frankfurters other than the potential for spoilage microorganisms and Listeria spp. Determining other taxa present on organic RTE franks is still being investigated, and the current research to the best of our knowledge is one of the first attempts to identify these communities using 16S rDNA sequencing, especially those highly contaminated with Listeria monocytogenes. Previous research investigating the microbial diversity between various ground beef products produced in South Korea using 16S sequencing  determined that Pseudomonas was the most abundant species (45.1%) among ground beef samples; however, Lactobacillus (16.4%), Acinetobacter (8.87%), Carnobacterium (6.49%), and Enhydrobacter (4.56%) were also major constituents of the core microbiota of ground raw beef [Proteobacteria (approximately 50%), Firmicutes , Bacteroidetes (<10%), and Actinobacteria (<10%) at the phyla level. At the genus level, Bowers [Pseudomonas (~25%), Psychrobacter (<10%), Acinetobacter (<10%), and Lactobacillus (<5%) as the core microbiota, although there was a large proportion of the microbiota defined as “undefined” or “other.” Among the beef frankfurters in the current study, although they were not cured, Firmicutes, and Proteobacteria were among the most prominent phyla across time , and Listeria, Lactobacillus, Bacillus, Pseudomonas, and Leuconostoc were among the most prominent genera of the microbiota.In addition, to looking at the mitigation of raw beef . In anotraw beef  investigraw beef  determin, Bowers  identifiFirmicutes (phylum) and Listeria (genus) being significantly different than 7 and 52 other taxa, respectively . Unsurprisingly, the microbiome (16S) data was heavily biased by the inoculation of frankfurters with L. monocytogenes, as demonstrated by the ANCOM results at both the phyla and genera level. These differences were expected as over 8 Log10 CFU/g of L. monocytogenes was attached to the frankfurters after inoculation on d 0. In addition, this data did indicate that all experimental treatments reduced the relative abundance of Listeria compared to the control which is in congruence with the microbiological plate data. As ANCOM does not produce pairwise comparisons but rather relatively different abundant taxa further inference is not plausible. However, numerically speaking, those treated with SL 1.56% and HDW + SL 1.56% appeared to have the least relative abundance of Listeria compared to all other treated frankfurters which did not not align with the microbiological data in the current study.To delineate the potential differences in taxa abundances among treated frankfurters, ANCOM was utilized at both the phylum and genus level across time. As such, there were differently abundant taxa at both the phyla and genus level with In addition to delineating differences among the identified taxa, it was important to detect any potential shifts of the α- (within differences) and β- (between differences) diversity in the current study across time. Significant shifts over time were expected among these diversity metrics as overall microbial loads typically increase over the shelf life of a product. Weinroth et al.  demonstrAlthough time was not significant, treatment did impact the microbiota. As such, those treated with TW had higher observed features (OTUs) than those treated with the no treatment control and a higher Shannon’s entropy than those treated with the no treatment control and SL 1.56%. It could be hypothesized that those treated with water had a greater richness due to the microbiota of tap water alone. Previous reports in the U.S. have demonstrated that tap water has a distinct microbiome that can contribute to the microbiome of downstream applications . HoweverThe only differences observed among the β-diversity metrics of the treated frankfurters were between the control and those treated with either SL 1.56% or HDW + SL 1.56% (Weighted Unifrac and Bray Curtis). Thus, the unique taxa present on frankfurters treated with the control were not the same as those identified on frankfurters treated with SL 1.56% or HDW + SL 1.56% and those unique taxa were phylogenetically unique or disperse.Listeria was different among the genera as the data was heavily biased by the inoculation of L. monocytogenes. As such, it was unclear of where these differences existed between the control treated franks and those treated with SL 1.56% alone or treated with HDW + SL 1.56%. Inferring from the mean relative abundant taxa at the genus level, it can be seen that those treated with SL, especially those treated with 1.56% SL, yielded greater proportions of Lactobacillus than those treated as the control or treated with SBS alone at 0.39 and 0.78%. This high proportion of one taxa could have contributed to these differences in Weighted Unifrac and Bray Curtis but because this was not delineated in ANCOM it cannot be determined within the confines of this study. Previous work where SL was incorporated into beef sausage batter demonstrated the ability of 1.2 to 1.6% concentrations of SL to reduce lactic acid bacteria (LAB) over a 60-day shelf life [Although β-diversity metrics display dissimilarities and differences of the microbiome and provide insight into the shifting microbiome, these metrics do not necessarily determine where these differences are occurring or what taxa are actively contributing to these shifts. Therefore, ANCOM is commonly utilized to further delineate differences. However, in the current study only elf life .Leuconostoc had the second highest differently abundant value at the genus level . Interestingly, the mean relative abundance of Leuconostoc was higher among franks treated with SBS (0.39%) compared to the controls and treated franks . Leuconostoc, a lactic acid-producing bacterium (LAB), has been demonstrated to be antagonistic towards L. monocytogenes [2 CFU/g of L. carnosum), L. carnosum was capable of exhibiting a bacteriostatic/bactericidal effect on L. monocytogenes through the acidification of its surroundings and direct nutrient competition. Although, Leuconostoc was not quantitated during the study using microbiological or molecular methods, it is important to note that the treatments with a high relative abundance of Leuconostoc such as those treated with SBS had the lowest recovered levels of L. monocytogenes. As such, the treatment of franks with SBS 0.78% reduced L. monocytogenes by 3.72 Log10 CFU/g reduction of compared to those designated as the control on d 21. As a follow up to these observations, it would be of interest to examine the direct response of Leuconostic spp. to SBS in pure culture studies to determine if there is some inherent tolerance of SBS by this microorganism.Although not significant when using ANCOM, ytogenes . Using mytogenes  determinPseudomonas among the mean relative abundant genera. Previously, Oh et al. [Pseudomonas aeruginosa inoculated frankfurters and hams demonstrated the combination of 10% sodium lactate and 10% sodium diacetate or the acidified solution of 5 or 10% sodium lactate (pH 3) was able to reduce Pseudomonas on the RTE meats by 2 and 4 Log10 CFU/g, respectively. Although we did not quantitate Pseudomonas using microbial or molecular techniques and current 16S sequencing pipelines are qualitative, the results demonstrated a potential decrease of Pseudomonas among those treated with SL.Among those treated with SBS at 0.39 and 0.78% there was also a higher numerical  relative abundance of h et al.  using soL. monocytogenes EDG-e population on frankfurters by at least 3 Log10 CFU/g, compared to no treatment control and 2 Log10 CFU/g compared to those treated with tap water alone. At the final time point, day 21, those treated with SBS 0.78%, had the lowest numerical recovery of L. monocytogenes EDG-e. On that same day, those treated with 0.39% of SBS had the least growth potential from d 0 (0.361 Log10 CFU/g). Although the growth potential of those treated with SBS 0.39% were no different than those treated with SBS 0.78%, SL 1.56%, and SBS + SL 0.39%, the growth potential of those treated with 0.39% SBS was at least 1 Log10 CFU/g less than that of the others. Additionally, this study demonstrated the potential for incorporating antimicrobial such as SBS and SL in the HDW or the exudate of frankfurters for control of L. monocytogenes. Throughout the experiment, no visible discoloration was observed, and no synergistic effects were demonstrated combining SBS and SL.According to USDA-FSIS, frankfurters are safe for consumption only for 2 weeks at 4 °C, refrigeration . In the L. monocytogenes EDG-e to short duration antimicrobial dip treatments applied post-lethality. Not only was the microbiota elucidated, but the treatment of the frankfurters with the experimental antimicrobial short duration dips was determined to be the key factor effecting the microbial shifts, with no effect of time. These results paired with the L. monocytogenes plate count data may provide evidence that these antimicrobials are effective at stabilizing the core microbiota irrespective of time. However, diversity metrics demonstrated there were differences between the TW treated franks and those treated as the control or with SL 1.56%. Although Listeria was the only significant different taxa using ANCOM, the diversity results are on par with the microbiota compositions of the different treated frankfurters. Ultimately, these results show the potential of these antimicrobials, SBS and SL, as short duration dips for the mitigation of L. monocytogenes and the potential for prolonged shelf life in refrigerated organic frankfurters. In addition, this study illustrates the potential utility of microbiome characterization as for assessing shelf-life microbial ecology of RTE products.In addition, this study is one of the first attempts at determining the microbiota response of organic uncured beef frankfurters inoculated with L. monocytogenes EDG-e, and did not follow the rigorous standards set by The French Agency for Food, Environmental and Occupational Health & Safety (ANSES), the European Union Reference Laboratory for Listeria monocytogenes, or the International Association for Food Protection [L. monocytogenes strains, adapting these strains to the cold environment (4 °C) prior to the study, and measuring water activity and pH of the frankfurters may have allowed the current research to capture the varying responses of L. monocytogenes strains to stressful environments [It is important to note that this study was conducted with one well studied strain, otection –83. By fronments . AlthougS1 Table(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S3 Table(DOCX)Click here for additional data file.S4 Table(DOCX)Click here for additional data file.S5 Table(DOCX)Click here for additional data file.S6 Table(DOCX)Click here for additional data file.S1 FigListeria monocytogenes, respectfully. Whereas 0.391 and 1.563% was inhibitory and bactericidal to Listeria monocytogenes, respectfully. The MIC and MBC of the combination of Sodium Bisulfate and Sodium Lactate was determined to be 0.391 and 0.781%.Results demonstrated that 0.195 and 0.391% of sodium bisulfate was inhibitory and bactericidal to (TIF)Click here for additional data file.


Multiplex polymerase chain reaction (mPCR) is increasingly being used to diagnose infections caused by respiratory pathogens in pediatric inpatient facilities. mPCR assays detect a broader array of viruses, with higher specificity and sensitivity and faster turnaround than previous assays. We adapted the FilmArray Respiratory Panel (FA-RP) for diagnosing respiratory infections. FA-RP is an in vitro mPCR assay that simultaneously and rapidly (in about 1 h) detects 20 pathogens directly from respiratory specimens. Here, we studied the clinical efficacy of FA-RP in children who underwent testing for respiratory pathogens at Yeungnam University Hospital from November 2015 to August 2018. From November 2015 to June 2016, routine mPCR testing was performed on nasopharyngeal swabs using the routine mPCR kit. From November 2016 to July 2018, mPCR testing was performed using FA-RP. A total of 321 tests by routine mPCR and 594 tests by FA-RP were included. The positive detection rates for routine mPCR and FA-RP were 71.3% and 83.3%, respectively. FA-RP reduced the lead time, waiting time, turnaround time, intravenous (IV) antibiotic use, and length of hospital stay for pediatric patients. The decreased use of antibiotics is expected to reduce antibiotic resistance in children. Acute respiratory infection (ARI) is a leading cause of hospitalization for young children. Among infants in the United States, the median cost of hospitalization due to infectious disease was 2235 USD, with total annual hospital costs of approximately 690 million USD . RespiraAlthough bacteria were previously considered to be the principal etiological agents of severe respiratory tract infections, the global impact of respiratory viruses has been increasingly recognized in recent years ,8,9,10. The emergence of antibiotic-resistant bacteria is a serious global challenge. Antibiotic resistance develops when bacteria adapt and grow in the presence of antibiotics. As the development of resistance is linked to the frequency of antibiotic use, the misuse and overuse of antibiotics hastens the development of bacterial drug resistance, rendering existing antibiotics less effective. In Korea, antimicrobials were most frequently prescribed to children younger than 10 years of age. The Korean government has implemented a series of healthcare policies that have resulted in the decrease of antibiotic prescription for the treatment of upper respiratory infections because the causative agents were mostly viral .Multiplex polymerase chain reaction (mPCR) for the diagnosis of respiratory pathogens is increasingly being used in pediatric inpatient facilities ,14. The The aim of this study was to determine the real-world clinical impact of FA-RP results on antibiotic use and hospital stay, particularly if antibiotic use was reduced as a result of decreased lead time.p = 0.007). C-reactive protein levels were not significantly different between periods, and lactate dehydrogenase levels were elevated during period III. However, these test results were not clinically significant . For routine tests performed during period I, negative results were obtained in 28.3% of samples, while 56.7% of samples tested positive for one virus and 15.0% tested positive for two viruses. However, in FA-RP, viruses were detected in 83.3% of samples. One virus was detected in 33.8% of all tests; two viruses were detected in 27.9% of samples; and more than three viruses were detected in 20.2% of samples. Bacteria were detected in 3.5% of samples and virus–bacteria co-infection was seen in 13 (2.2%) of samples tested by FA-RP  was the virus most frequently detected during period I , followed by respiratory syncytial virus (RSV)  and adenovirus (AdV) . During period III, HRV and human enterovirus (HEV) were most frequently detected , followed by RSV  and parainfluenza viruses (PIV)  .p < 0.001)  .p = 0.002). There was no significant difference in the frequency of oral antibiotic use during the study period. There was no significant difference between the frequency and duration of IV antibiotic use between period I and period II. However, between period I and period III, the frequency of use of IV antibiotics, duration of use, and period of use of IV + oral antibiotics decreased significantly (p = 0.015). The length of hospital stay was significantly reduced in period III when compared to period I (p = 0.004).The frequency of intravenous (IV) antibiotic use during period I using the routine test was 51.7%, and the rates of antibiotic use during periods II and III using FA-RP were 52.7% and 39.4%, respectively. In particular, the frequency of IV antibiotic use decreased significantly during period III  of whom tested positive and 10 (16.9%) tested negative. Ten discharged patients underwent routine testing, six of whom tested positive and four of whom tested negative.We compared two respiratory pathogen tests performed during a three-year period and compared the clinical management and patient characteristics with respect to the method of pathogen testing. We have reported in a previous study that the use of FA-RP significantly reduces the mean waiting time, TAT, and lead time compared to the routine test . While aThe impact of reverse transcription (RT)-PCR testing on clinical management, antibiotic use, and the length of hospital stay for children with respiratory infections has been studied, with respiratory sample results being reported to clinicians within 12–36 h for the study group and after 4 weeks in the control group. In this case, rapid reporting did not result in a change in patient care. There were no significant differences between the groups with respect to hospital admission, length of hospital stay, or duration of antibiotic use. The authors concluded that although RT-PCR testing had a high yield of viral diagnoses, rapid communication of these results did not lead to shorter hospital stay, decreases in hospital admissions, or decreased antibiotic use for children with ARIs .pertussis and Mycoplasma and Chlamydia infections during periods II and III was not high.In a similar randomized trial in adults, the mPCR results were available in 24 h for the study group and in 7 days for the control group. mPCR testing for respiratory viruses with results available within 24 h did not reduce the consumption of bacterial antibiotics or the length of hospital stay in adults in the emergency unit . HoweverIn a previous randomized controlled trial on the impact of early and rapid diagnosis of viral infections in children with febrile respiratory tract illness in the ED, children were randomly assigned to either undergo mPCR or routine care . mPCR teThe Infectious Disease Society of America guidelines suggest the use of rapid viral testing for respiratory pathogens as a way to reduce the inappropriate use of antibiotics. However, as of now, it is only a weak recommendation due to low-quality evidence. Although rapid viral testing has the potential to reduce the inappropriate use of antibiotics, the results have been inconsistent . Our resKreitmeyr et al. conducted a prospective study on antibiotic stewardship programs (ASPs) that aim to reduce antibiotic consumption. ASPs targeted the infectious diseases (ID) ward rounds (prospective audit with feedback), ID consultation services, and internal guidelines on empiric antibiotic therapy. The study concluded that the implementation of an ASP was associated with a profound improvement in rational antibiotic use, and no adverse effects regarding the length of hospital stay or in-hospital mortality were observed .In our study, with the introduction of the FA-RP test, the test time was shortened, but there was no significant difference in the frequency and duration of antibiotic use between periods I and II. However, over time, in period III, the frequency and duration of antibiotic use were significantly decreased. This suggests that despite the introduction of effective tests, it takes time to implement ASPs and to change clinical practice.Staphylococcus aureus (MRSA) correctly. In addition, 81% of participants said that ASP was not properly handled during their medical training, and 71% said they did not learn appropriate examples from their tutors. Therefore, proper ASP education for medical doctors is very desperately needed [In the study of young Italian doctors’ knowledge, attitudes, and practice of ASP, only 20–40% of doctors answered vancomycin-resistant enterococci (VRE), carbapenem-resistant Enterobacteriaceae (CRE), extended-spectrum β-lactamase-producing enterobacteria (ESBL), and methicillin-resistant y needed .In this study, we analyzed the usefulness of two viral tests performed at different times in patients who visited the hospital for respiratory disease and fever. Since the emphasis was placed on comparing the effectiveness of the tests, the patients’ clinical characteristics were not analyzed in detail.In our study, there were viral–viral co-infections and viral–bacterial co-infections. Several studies have been conducted on the clinical significance of viral co-infection. It is known that co-infection between viruses and interference between viruses can occur. In particular, it is known that RSV accounts for most childhood infections . AlthougWhile complex policy changes and management are an important part of ASPs, it is a challenging task, requiring time, effort, and careful implementation. Our findings are significant as they demonstrate that simply changing to an mPCR kit with a faster TAT resulted in reduced antibiotic use. Careful management of antibiotics, the use of ASPs, and targeted medical education to pediatricians and pediatric hospitals are important for the overall reduction of antibiotic use ,23,26. BIn conclusion, despite the limitations of the study, TAT was shortened through mPCR tests, and it was confirmed that the use of antibiotics could be reduced. In the future, it will be necessary to apply a rapid mPCR test to pediatric patients who need to consider antibiotic prescription due to febrile illness and respiratory disease in order to reduce duration of antibiotics, hospitalization period, and medical costs.We conducted a retrospective cohort study of children hospitalized at Yeungnam University Hospital from November 2015 to August 2018, who underwent testing for respiratory pathogens either in the ED prior to admission or within the first 2 days of hospitalization. Virus tests were performed on patients with fever accompanied by diseases of the respiratory system, such as URI, bronchiolitis, pneumonia, croup, and tonsillitis. We excluded patients with chronic disease requiring treatment for more than 3 months and infants under 29 days of age. From November 2015 to June 2016 (period I), routine mPCR testing was performed on nasopharyngeal swabs by using the AnyplexTM II RV16 detection kit . From July 2016 to July 2018 (periods II and III), newly adopted mPCR testing was performed on nasopharyngeal swabs by using the FA-RP . We divided this period into periods II (2016.7.1 to 2017.6.30) and III (2017.7.1 to 2018.7.31). After the introduction of the rapid mPCR test method, we conducted a study by dividing the period by one year to check whether medical practices such as antibiotic prescription and hospital stay changed.The medical records of enrolled patients were retrospectively reviewed to confirm laboratory results, identify patient characteristics, and determine the duration of oral and intravenous (IV) antibiotic use and that of hospitalization. mPCR testing was used to detect viruses and bacteria. Positive detection rates of viruses and bacteria were determined. The waiting time (time from prescription to submission of a specimen to the laboratory), TAT , and lead time  of the routine test and FA-RP test were analyzed. The indications for antibiotic use were a negative result on the mPCR test; unstable clinical symptoms before the virus test result; or elevated levels of inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and procalcitonin.This study was approved by the institutional review boards (IRB) of Yeungnam University Hospital . Informed consent was waived due to the retrospective nature of this study.The routine mPCR test for detecting respiratory viruses was performed using the Anyplex II RV16 detection kit. RV16 can detect 16 viruses: AdV, influenza A, influenza B, PIV 1–4, HRV, bocaviruses, coronavirus , HEV, RSVA, RSVB, and metapneumovirus (MPV) . The rouBordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae [The newly adopted mPCR test for detecting respiratory viruses was performed using the FA-RP, which targets 20 viruses and bacteria: AdV, coronavirus , MPV, HRV/HEV, influenza A, influenza A/H1, influenza A/H3, influenza A/H1-2009, influenza B, PIV 1–4, RSV, eumoniae . The FA-t-test was used to compare laboratory values, duration of hospital stay, and antibiotic use. Statistical significance was defined at p < 0.05.The statistical package SPSS version 25.0 was used to analyze the data . Categorical variables were compared using Pearson’s chi-square test to compare patient characteristics, frequency of pathogen, and antibiotic use. The


However, in the case of post curing, resin appears to preserve its mechanical properties at high temperatures, which results in the appropriate structural performance of FRP-reinforced/strengthened members at high temperatures that are below the resin decomposition temperature dT. Given the research gaps, recommendations for future studies have been presented. The discussions, findings, and comparisons presented in this review paper will help designers and researchers to better understand the performance of concrete structures that are reinforced/strengthened with FRPs under elevated temperatures and consider appropriate approaches when designing such structures.Several experimental and numerical studies have been conducted to address the structural performance of FRP-reinforced/strengthened concrete structures under and after exposure to elevated temperatures. The present paper reviews over 100 research studies focused on the structural responses of different FRP-reinforced/strengthened concrete structures after exposure to elevated temperatures, ranging from ambient temperatures to flame. Different structural systems were considered, including FRP laminate bonded to concrete, FRP-reinforced concrete, FRP-wrapped concrete, and concrete-filled FRP tubes. According to the reported data, it is generally accepted that, in the case of insignificant resin in the post curing process, as the temperature increases, the ultimate strength, bond strength, and structure stiffness reduce, especially when the glass transition temperature  Fibre-reinforced polymer is a composite material that consists of a polymer matrix and fibre reinforcement. Numerous FRPs have been produced, including basalt fibre-reinforced polymers (BFRP), glass fibre-reinforced polymers (GFRP), aramid fibre-reinforced polymers (AFRP), and carbon fibre-reinforced polymers (CFRP) ,2,3,4. FgT) of the resin degrades the mechanical properties of FRP materials [gT is normally represented by a single gT (often between 50 and 120 °C for resins cured at ambient temperatures), which can be evaluated experimentally using differential scanning calorimetry (DSC) or determined by dynamic mechanical analyses (DMA) [gT is frequently used as a “critical temperature”, although mechanical performance degrades prior to reaching gT [Due to concerns about the performance of FRPs at high temperatures, the widespread application of FRP-RC in structures has been limited ,23,24. Iaterials . Tg is nes (DMA) ,26. In dching Tg . When suching Tg ,28,29,30ching Tg ,32. Thesching Tg ,34. Deurching Tg  is one oching Tg  conducteThe purpose of this review is to summarise and discuss the findings of investigations on the performance and mechanical properties of FRP-reinforced/strengthened concrete members under elevated temperatures.FRPs exhibit significantly different behaviours from steel or concrete at high temperatures. When exposed to a substantial amount of heat, all polymer matrix composites will burn. Additionally, matrix elements, such as epoxy, vinylester, and polyester, not only facilitate burning but also produce huge amounts of dense black smoke . FurthergT are applied to the resin matrix, the resin matrix remains relatively unaffected  and the surface of the resin matrix remains rough and similar to that of the unconditioned sample [gT, the resin undergoes a phase transition from glassy to rubbery. In this instance, the FRP materials soften and creep, resulting in a significant loss of stiffness and strength [When elevated temperatures below d sample . In thisstrength . It has strength ,48. At hstrength . Figure The compression and interlaminar shear failure of FRP composites occurs at substantially lower loads and temperatures than flexure and tension . ElevateA few of the parameters that influence the properties of FRPs are the configuration of fibres and resin, the production technique, and the quality control of the final products. The stiffness and strength properties of FRPs decrease with increasing temperature, although there are considerable variations in the results due to the wide variety of fibre volume fractions, formulations of the matrix, and fibre orientations represented in the data ,51.2S). At 900 °C, the C–S–H fully degrades. As a result, the critical temperature range for concrete is around 400–900 °C and concrete loses the majority of its strength within this range [While concrete generally has a high resistance to fire, its mechanical characteristics, such as elastic modulus and strength, degrade when exposed to high temperatures. At elevated temperatures, the failure is mostly due to the creation of cracks that are parallel to the heated surface, changes in the chemistry, and an increase in pore pressure owing to water evaporation. At elevated temperatures, concrete undergoes a variety of physical , chemical , and mechanical  phenomena that degrade its qualities ,53. The is range . FRPs and concrete could be used to construct different structural systems ,60,61. FgT is one disadvantage of epoxies, which may occur around 40–50 °C for the commercially available epoxy resins that are used in structural engineering. At that temperature, the epoxy polymer transforms from a stiff to a viscous (soft) state, reducing the adhesion between the reinforced element and the FRP laminate. As a result, the majority of EBR–FRP solutions are vulnerable to high temperatures. It is not usually clear whether the issue is limited to fire conditions or whether it may also occur as a result of sun exposure [The majority of options for fibre-reinforced strengthening by external bonding are based on polymer systems, most notably those of epoxies . Typicalexposure ,64,65,66gT of bonding adhesives that are cured at the ambient temperature (commonly epoxy resins), which is normally between 45 and 80 °C. Upon service temperatures above the gT value, the adhesive changes from a solid to a viscous state, resulting in a loss of strength and stiffness. Such bonding adhesive property degradations impair the bond behaviour of the interface, resulting in the stress transfer loss between materials and the early debonding failure of the FRP laminate [−6/°C at ambient temperatures. Consequently, the aforementioned thermal incompatibility could cause large thermal stresses at the interface of these two materials, thereby affecting the load-bearing capacity of the strengthened structures [Thermal loading affects the bond behaviour of the interface of FRP and concrete in two ways, which influences the stress transmission between the FRP and the concrete as well as the load-bearing capacity of the FRP strengthening system. Property changes in the bonding adhesive and the two adhesives induced by the temperature are caused by the first effect, whereas the second effect is caused by the thermal incompatibility of FRP and concrete. The first effect is due to the low laminate ,67,68. Tructures . This issue is not limited to fire conditions; it can also develop after being warmed by the sun’s rays. In a study by Krzywoń , concretDespite the vulnerability of epoxy resin to elevated temperatures, post curing of resin during exposure to elevated temperatures may cause some strength improvement . It was In order to numerically model FRP reinforced concrete structures, concrete is often simulated as a nonlieanr material using a model derived by Williams and Warnke . In theiτ is the bond stress corresponding to the given slip (S) in (MPa), S is the relative slip corresponding to a given shear stress in (mm), and In terms of modeling FRP composites, the material characteristics of FRPs are normally considered orthotropic and elastic until reaching to the ultimate strength, which it drops to zero . The bonAdditionally, a suite of numerical fire simulation software is also being developed in the experimental program, ,79. CompAlong with standard numerical approaches, a homogenisation approach ,81 has bHawileh et al.  establisgT in the CFRP does not necessarily result in the failure of CFRP-strengthened RC beams and that more realistic fire limit states should be developed. Several further computational models [Kodur and Ahmed  and Ahmel models ,87,88 fogT and decomposition temperature dT) results in a better performance in moderate temperatures  and under fire conditions . gT may cause bond loss even at moderately elevated temperatures, which results in the loss of interaction between the FRP and the concrete. In the literature, there have been a lot of studies on the bond characteristics of FRP bars used for concrete strengthening at high temperatures [gT of the bars; considerable bond strength reductions are found at temperatures corresponding to the lowest gT identified for the bars based on the commencement of a decline in the storage modulus of the bars [For transferring loads through the polymer adhesive or matrix, a strong bond between the concrete and the FRP is required . The deteratures ,97,98,99eratures ,47. A noThe durability of the interface bond between concrete and FRP bars was investigated experimentally, with an emphasis on the deterioration of the surface material of the FRP bar when employing a concrete mix with a high compressive strength. For bond strength tests, 48 pull-out samples were cast, consisting of four distinct types of FRP bars. Additional samples were cast for the concrete compressive strength test. The samples were subjected to the following conditions: tap water kept at 60 °C or room temperature and air that was thermally cycled from −20 to 60 °C. Reductions of 0–20% in bond strength were seen for GFRP bars and reductions of 4–10% were reported for CFRP bars after environmental conditioning. Before reaching the peak bond strength, the conditioning increased the free-end slip. It was reported that the deterioration of the bond primarily resulted from the corrosion of the FRP bar and was less due to the concrete .Several numerical studies were also conducted to evaluate the influence of different parameters and predict the performance of FRP-reinforced concrete ,103,104.Some research publications have looked into the strength of various FRP-reinforced elements ,106,107.Another study found that shear failure is the most common mode of failure in hybrid concrete beam specimens that are reinforced with GFRP when exposed to temperatures ranging from 300 to 700 °C and subjected to monolithically raised static loads until failure. Around a 53% reduction in the ultimate load capacity was observed in the hybrid reinforced concrete beam when subjected to 700 °C in comparison to ambient temperatures, according to the findings . The fatHajiloo et al.  performeRafi et al.  developeLin and Zhang  developegT. However, it was observed in several studies that under very high temperatures, as well as fire conditions, the structure can still carry a considerable load despite the significant bond strength reduction. This may be due to the fact that FRP bars are embedded in concrete and are not directly exposed to heat and oxygen. gT, the rapid loss of stiffness and strength occurs in commonly used adhesives and polymer matrices. For externally bonded systems, the crucial gT depends on the individual polymer matrix composition, among other considerations. FRPs may ignite and facilitate the propagation of flames and the production of poisonous smoke if left unprotected in a fire [Over the past two decades, research projects all over the world have studied the behaviour of externally bonded FRPs that were used for reinforcing RC structures. The exterior of the RC structures is connected to FRPs, often with an epoxy resin adhesive, which provides extra tensile or confining reinforcement, in addition to the internal reinforcing steel. There has now been enough study and execution to produce numerous guidelines and design codes for using FRPs in conjunction with concrete structures ,118. In n a fire .gT of the epoxy resin (100 °C), a small loss in strength occurred in both GFRP- and CFRP-wrapped specimens, which resulted from the epoxy melting. At 200 °C, the strength loss was more noticeable. The efficiency of the FRP confining system that was bonded with epoxy diminished significantly , but did not vanish as the temperature increased, particularly in the region of the epoxy resin/adhesive gT [As a result, much more research is needed to fully comprehend the performance of structures that are strengthened with FRPs in terms of fire resistance. Al-Salloum et al.  investigesive Tg .A numerical model for the prediction of the response of FRP-wrapped RC circular columns with thermal insulation to fire was developed by Bisby et al. . The modIt is well-known that, in harsh environments, carbon steel tubes are highly susceptible to being corroded after prolonged contact with acid rain, seawater, and other aggressive agents ,133. To In a similar study conducted by Tabatabaeian et al. , the progT may result in bond loss, even at moderately elevated temperatures , which results in the loss of FRP–concrete interaction. Significant ultimate strength reductions also occur when FRP-reinforced beams are exposed to fire . However, the retention is significantly affected by the concrete cover, FRP bar type and diameter, and the thermal properties of the components. Given the discussion and findings presented in this review, more experimental and numerical studies are needed to develop comprehensive predictive models that are capable of predicting the structural performance of FRP-reinforced/strengthened concrete when exposed to elevated temperatures. The present paper provided a fundamental insight that could be used to develop or enhance new and existing design codes/standards for FRP-reinforced/strengthened structures.A systematic overview and discussion regarding the structural performance of FRP-reinforced/strengthened concrete members after exposure to elevated temperatures was presented. Although FRP-reinforced/strengthened concrete members provide many benefits, their vulnerability to elevated temperatures remains a challenging concern. By reviewing the research conducted on concrete strengthened with FRP composites, one can conclude that their performance when subjected to elevated temperatures is well studied. In addition to the experimental data, analytical models have been developed to predict tensile and bond strength reductions of FRPs at elevated temperatures. In terms of the bond between FRPs and concrete, it has been shown that the thermal loading affects the bond behaviour through influencing (i) the stress transmission between the FRP and the concrete and (ii) the load-bearing capacity provided by the FRP system. It is generally observed that the degradation of the resin’s mechanical characteristics at temperatures exceeding Sufficient implementations and investigations have now been conducted to develop numerous guidelines and design codes for the application of FRPs in conjunction with concrete structures. Following the discussion presented in this paper, it can be concluded that more experimental and numerical research studies are required to address several research gaps regarding the performance of FRP-reinforced/strengthened concrete members under elevated temperatures. The following research topics are therefore recommended for future studies to fill some of these gaps:(1)Applying cyclic and impact loading to FRP-reinforced/strengthened concrete members under elevated temperatures in order to study their dynamic behaviour after exposure to elevated temperatures. Currently, most studies have been conducted under static loading. (2)The current experimental data can be used to verify/calibrate finite element numerical models and then comprehensive parametric studies can be conducted to investigate the effects of different parameters, such as material thermal and mechanical characteristics, resin curing ratio, fibre type and orientation, heating rate, etc.(3)Conducting tests using real fire. Currently, most studies have been conducted under electrical furnace conditions. It is expected that the performance of structural members under real fire conditions may be significantly different from that of simulated standard fire testing. (4)Studies on concrete filled FRP tubes under elevated temperatures are very limited. Therefore, several effective parameters, such as fibre type and orientation, tube geometry , surface friction coefficient (in the case of studying the bond between the concrete and the tube), etc. are yet to be investigated. (5)Conducting full-scale tests to investigate the effect of stress redistribution and structure size effect.