What is the reason for the swelling bag after the beef packaging is cooked at high temperature?

Product expansion bags can be divided into physical expansion bags and bacterial expansion bags. 1Physical expansion of the bag, mainly due to the vacuum degree of the bag can not meet the requirements when vacuum sealing. In addition, during high-temperature sterilization, since the pressure in the bag is greater than the pressure in the pot, it is necessary to add back pressure for sterilization. Improper control of the back pressure can easily cause physical swelling of the bag. 2, Bacterial swelling bag is due to incomplete sterilization and the reproduction of gas-producing bacteria in the product.a.Beef was heavily contaminated before sterilization. The time required for all the spoilage bacteria or spores to die varies with the number of original bacteria. In the production process, from raw material processing to bagging sterilization, they are all subject to different degrees of microbial contamination. The semi-finished products are stored for a long time, causing thermal deterioration, which will result in incomplete sterilization at the same time.b.The sterilization device or sterilization process is unreasonable, resulting in incomplete sterilization. Reasonable sterilization device and sterilization process are to ensure complete sterilization. Reasonable sterilization device and sterilization process are necessary conditions to ensure complete sterilization. At present, most of the factories in our country use the horizontal sterilizer that is standing and intermittent. If the steam convection in the pot is not smooth or the air in the pot is not cleaned cleanly when the temperature is raised, it is easy to cause uneven heating of the product and affect the sterilization effect.