Generally speaking, perishable foods need to be preserved and transported through cold chains, which mainly include fruits and vegetables, meat and eggs, aquatic products, etc., as well as processed foods such as quick-frozen foods, ice cream and dairy products. A complete cold chain includes the following links: pre-harvest after harvest, food processing refrigeration equipment, road (railway, ocean) refrigerated transport, low temperature storage, distribution, retailer cold storage, refrigerated display cabinet. According to reports, China’s total annual loss in cold chain transportation is as high as 7.5 billion yuan.
Temperature is undoubtedly the number one killer of the cold chain. All foods contain microorganisms. The key to controlling food safety and quality in the circulation process is to control the growth rate of microorganisms. The most important thing to control the growth of microorganisms is to control the temperature. The increase of temperature will lead to an increase in the number of spoilage bacteria and pathogens in food. . In general, when the temperature is increased by 6 ° C, the growth rate of bacteria doubles and the shelf life is shortened by half.
Experts pointed out that due to the accumulation and irreversibility of quality degradation caused by temperature changes in refrigerated foods, there are corresponding technical indicators for product control and storage time for different product varieties and different quality requirements. A complete cold chain requires consistent temperature throughout the supply chain. Once the cold chain breaks, the temperature exceeds the allowable fluctuation range, beyond the storage stability of the food itself, the microorganisms will accelerate the reproduction, and the nutritional quality of the food will accelerate the loss, even if the temperature returns to the optimal storage temperature, microbial level, quality and nutrition. Irreversible damage has occurred.
In addition, the quality of the cold chain is also affected by many other factors. The first is raw materials, processing technology and packaging. They can also show excellent synergistic value for maintaining food quality under cold chain conditions. Secondly, specific technical operations such as cooling and cleaning in the cold chain are also low temperature and perishable. The technical and theoretical basis that food processing and circulation must follow, the mechanical trauma in operation, and the unclean and polluting environment can alleviate the quality loss of perishable food in the cold chain environment. These factors work together on the quality of the cold chain, and the quality of the cold chain determines the safety of the food.
