The vacuum quick cooling of cooked food is to use vacuum cooling technology, so that the food can pass through the rapid propagation zone of food bacteria between 25 and 50 ℃ in a vacuum state at an extremely fast cooling rate, so that the temperature of cooked food is reduced to below 10 ℃. Avoid secondary pollution before the product is packaged. This improves the quality and safety of the food and extends the shelf life.
Modified atmosphere fresh-keeping packaging is also known as gas replacement packaging, which is called MAP internationally. The principle of the composite modified atmosphere packaging machine is to use composite fresh-keeping gas (2-3 kinds of gases are mixed according to the food characteristics) to replace the air in the packaging box or packaging bag, change the storage environment of the food in the PP MAP Tray, and inhibit bacteria (microorganisms). ) growth and reproduction, thereby extending the shelf life or shelf life of food. Different foods have different components and proportions of fresh-keeping gas.
In the process of storage, transportation and sales of finished products, the temperature is always controlled within the range of 0 to 4 °C, so that the product preservation period is more than 7 days. Compared with the traditional processing technology, the whole process flow has the characteristics of reasonable flow, convenient operation and low energy consumption. Cooked food packaged with MAP is always healthy and hygienic, with bright colors, fresh taste, vivid appearance, full juice and rich nutrition.
In addition to strict requirements on raw materials, the food cooking and processing standards and retention time are very important in the modified atmosphere fresh-keeping packaging of cooked food. Immediately after cooking, cooked food needs to be quickly cooled in vacuum and packaged in an environment below 20°C. If the processing sanitation conditions at this stage are poor, such as pathogenic bacteria and knives in the air, and insufficient disinfection of tableware and operators, the food will be contaminated again. , although CO2 in the composite gas can inhibit the proliferation of residual bacteria, it still affects the shelf life of food to a certain extent.
Modified atmosphere packaging of cooked food is a lag period that relies on carbon dioxide to inhibit the growth and reproduction curves of most aerobic bacteria and fungi. Therefore, the less bacterial contamination before the packaging of cooked food, the better the bacteriostatic effect and the longer the shelf life.
4. External factors affecting the shelf life of modified atmosphere fresh-keeping packaging products:
1. Temperature control: including environmental temperature control for processing, packaging, storage, transportation and sales.
2. Hygiene management: product processing and packaging adhere to good hygiene management (GMP) and implement HACCP management system.
3. Raw material quality: initial bacterial count and physical and chemical indicators such as peroxide value (PV), thiobarbituric acid value.
4. Other ingredients in the final product.
5. Time interval from processing to packaging.
6. The ratio of gas to product volume.
7. Mixed gas proportioning accuracy and residual gas composition (residual oxygen %).
8. The air permeability of O2/, CO2 and N2 of the packaging material.
Therefore, controlling every link and condition of the packaging, storage and transportation of food, and putting it on the shelf is a necessary factor to make cooked food products achieve the most ideal fresh-keeping effect. Only strict control and management can maximize the shelf life of food preservation, so that enterprises can obtain the greatest economic and social benefits.
