STATEMENT REGARDING GOVERNMENT FUNDING

This invention was not made with government support.

TECHNICAL FIELD

The present disclosure generally relates to food processing, and in particular, to a cooling apparatus suitable in food processing technology.

BACKGROUND

This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.

Over the years, there has been a considerable amount of effort to improve quality of thermally processed foods and retain nutrients as much as possible. This is usually done through optimization of the thermal process and selecting the time-temperature combination that will result in a food product with maximum nutrient retention without compromising food safety objectives. The goal of thermal processing of foods is the destruction of microbes that can result in harmful effects both for human health and food spoilage. Retort thermal processing is one of the oldest forms of processing low acid foods. In such processing, there are two competing interests: 1) destruction of microbes, while 2) preserving quality of food. Due to the heat load in a retorted container, the quality of the product is often compromised in order to achieve the commercial sterility.FIG. 1is a graph of time in minutes vs. temperature in ° C., which represents the effect of time and temperature on spore destruction and retention of quality in food products. Higher temperature inactivates the microorganisms faster than the nutrients such as vitamin C. This is due to the fact that the nutrients are more resistant to heat than the microorganisms. The operating temperature ranges of aseptic thermal processes are designed based on the optimization of quality while keeping the food safe from microorganisms of concern. Hence, aseptic processing is conducted at much higher temperatures than the retort process.

A significant advancement in thermal processing was processing the product at higher temperatures for significantly shorter times (High Temperature Short Time, HTST or Ultra High Temperature, UHT processing systems), where the product is sterilized separately from the containers and then filled and sealed in a sterile environment. The entire system is known as Aseptic processing and packaging. Advantages of aseptic systems over conventional thermal processing systems (e.g. retorts) were that the product could be heated up rapidly in a continuous format separate from the container. Due to shorter retention times and less heat abuse, aseptic processing allows the industry to retain higher amounts of quality nutrients compared to conventional canning processes.

Over-heating and under-heating are two major concerns for the food industry. Due to food safety concerns and limitations of the proper control systems, the food industry tends to over-process the products. To ensure a safe product, heat-resistant pathogenic or spoilage organisms that grow at expected storage temperatures must be considered. One such organism isClostridium botulinumin low-acid foods. The thermal process is designed in such a way that the probability of survival ofC. botulinumspores in low-acid foods is no higher than one in 1012. If the thermal process is more conservative in nature, then it tends to over-process the product. Over-processing of the food product leads to the loss of vital nutrients and lower overall quality of the product, whereas under-heating the product leads to product spoilage due to microbial growth and poses health concern for the consumers. Hence, it is important to optimize the processing conditions to achieve the highest nutritional retention and keep the product safe from microorganism growth at the same time.

No matter how the heating takes place, once heated, the food needs to be cooled prior to packaging. Any improvement in exposure time during the cooling phase of the aseptic process would bring many benefits and enhance the benefits of recently developed heating technologies (e.g. continuous microwave heating). However, there has been a lack of attention in cooling technology development that can further maximize the nutrient retention and provide better quality food to consumers. In addition to quality improvement, the availability of a rapid cooling technology will provide opportunities to save initial capital and energy costs and to make the manufacturing process more sustainable. However, the cooling cannot be such that there is a phase change, i.e., liquid to solid, e.g., by freezing the product.

Therefore, there is an unmet need for a novel approach in cooling or rapid cooling foods that have been heated for the purpose of destroying microorganism that avoids a phase change in the product during the cooling process.

SUMMARY

A rapid cooling system for processing food is disclosed. The system includes a heat exchanger adapted to receive a first coolant (Coolant-I) at a first temperature and eject the first coolant at a second temperature. The system also includes a cooling chamber disposed within the heat exchanger in thermal communication with the heat exchanger. The cooling chamber includes a first inlet adapted to receive a product at an elevated temperature (T1), a second inlet adapted to receive a second coolant (Coolant-II) at a low temperature (T2), and an outlet adapted to release a combination of the product and Coolant-II at a low temperature (Tout) and pressure (Pout). The cooling of the product from T1to Toutdoes not cause a phase change in the product.

A method of rapidly cooling food products in food-processing is also disclosed. The method includes inletting a first coolant (Coolant-I) at a first temperature into a heat exchanger. The method also includes ejecting Coolant-I at a second temperature from the heat exchanger. Additionally, the method includes inletting a product at an elevated temperature (T1) via a first inlet into a cooling chamber in thermal communication with the heat exchanger. Furthermore, the method includes inletting a second coolant (Coolant-II) at a low temperature (T2) via a second inlet into the cooling chamber. The method also includes releasing a combination of the product and Coolant-II at a low temperature (Tout) and pressure (Pout) via an outlet from the cooling chamber. The cooling of the product from T1to Toutdoes not cause a phase change in the product.

