Evaluation of cultivar susceptibility and storage periods towards aflatoxin B1 contamination on pistachio nuts
Aflatoxins (AFs) are potent sources of health risks to both humans and animals. Among them, AFB1 is the most hazardously toxic and the most frequent in various food commodities, including pistachio nuts. In this survey, the effect of the storage period on AFB1 accumulation on pistachio nuts was investigated. A total of 49 samples collected during the crop year of 2005 from the most cultivated pistachio cultivars in Tunisia were rapidly screened by enzyme-linked immunosorbent assay (ELISA) combined with an immunoaffinity step. The obtained results showed that the contamination of pistachio nuts has occurred clearly after two years of storage for all the tested cultivars except the case of Mateur variety and Thyna ecotypes. In this study, the cultivar Mateur was found to be the most susceptible cultivar to contamination by AFB1. After 4 years of storage, the average contamination levels in nut samples ranged from 2.7 ± 0.3 to 12.7 ± 2.2 µg/kg for AFB1, according to the cultivar. These levels exceeded the maximum permitted limit of 2 µg/kg set by the European Commission in nuts.
Potential preventive role of lactic acid bacteria against Aflatoxin M1 immunotoxicity and genotoxicity in mice
Abstract Aflatoxin M1 (AFM1) is a mycotoxin produced by numerous Aspergillus species in pre- or post-harvest cereals and milk. Exposure to AFM1 imparts potent economic losses in the livestock industry. Toxicologically, it also causes severe immune system problems. The aims of this study were to evaluate a new AFM1-binding/degrading microorganism for biologic detoxification, to examine its ability to degrade AFM1 in liquid medium, and to evaluate its potential for in vivo preventative effects against AFM1-induced immunotoxicity and genotoxicity in mice. Lactobacillus plantarum MON03 (LP) isolated from Tunisian artisanal butter was found to display significant binding ability to AFM1 in PBS (93%) within 24 h of incubation. Further, the LP was able to tolerate gastric acidity, bile salts, and adhere efficiently to Caco-3 cells in vitro. The in vivo study used Balb/c mice that received either vehicle (control), LP only (at 1 × 109 CFU/L, ∼1 mg/kg bw), AFM1 (100 mg/kg bw), or AFM1 + LP daily for 15 days (by gavage); two other groups received a single dose of colchicine (4 mg/kg) or mitomycin C (1 mg/kg) as positive controls for induction of micronuclei and chromosomal aberrations, respectively. The results showed that, compared to in control mice, AFM1 treatment led to significantly decreased body weight gains, and caused cytotoxic/genotoxic effects as indicated by increases in frequencies of polychromatic erythrocytes, as well as those with micronucleation (PCEMN) and chromosomal aberrations, among bone marrow cells. The concurrent administration of LP with AFM1 strongly reduced the adverse effects of AFM1 on each parameter. Mice receiving AFM1 + LP co-treatment displayed no significant differences in the assayed parameters as compared to the control mice. By itself, the bacteria caused no adverse effects. Based on the data, it is concluded that the test bacteria could potentially be beneficial in the detoxification of AFM1-contaminated foods and feeds for humans and animals.
Relationship between Fusarium graminearum and Alternaria alternata contamination and deoxynivalenol occurrence on Argentinian durum wheat
A mycological survey was carried out on durum wheat (Triticum durum) samples from the main production area of Argentina. The isolation frequency and relative density of species of dematiaceous fungi, and genus Fusarium were calculated. Alternaria alternata and Fusarium graminearum were the predominant fungal species. An analysis of deoxynivalenol (DON) natural contamination was also performed on a limited number of samples (60). DON contamination levels in positive samples ranged from 26 to 6400 μg/kg. The non-parametric techniques applied showed that there is a positive relationship between DON contamination and F. graminearum relative densities and a negative relationship between DON contamination and A. alternata relative densities.