As the social development pace speeds up nowadays, packaging bag for meat products has become a great demand. Meat products are typically packaged with highly resistant packaging material (PET/pure aluminum/CPP or PPET/PA/CPP for three-layered structure; or PET/pure aluminum/PA/CPP for four-layered structure). Besides, the bags shall be sterilized to prolong the shelf life during storage and transportation.

For unique features of meat products, foods shall be sterilized at high temperatures normally by two methods: high temperature and high pressure method; and low temperature and normal pressure method. Both methods have their own advantages. Due to relatively low heating temperature, the low temperature and normal pressure method well maintains the fiber, tender taste and all nutrient elements of the meat. However, since only the pathogenic bacteria are killed at low temperatures and a great number of spoilage bacteria are still alive, the service life of the product will be shortened to cause waste in the transportation. On the contrary, high temperature makes the meat fiber excessively shrunk to lower its taste, but it kills all bacteria, including the spoilage ones, to greatly extend the food’s service life.

Packaging bag may be expanded during the steaming/stewing sterilization, processing and cooling process for different reasons. Solutions may be adopted specific to the reason. At first, pressure in the sterilization equipment shall be kept balanced with that in the packaging bag, thus reaching the sterilization temperature required. Apart from the equipment temperature or positive/negative pressure, it may also be caused by the temperature. The higher the temperature, the greater it expands. Therefore, it’s very important to lower the temperature and extend the sterilization time, thus radically killing out the bacteria and ensuring safety of the food transportation.