(1) Completely aseptic packaging
It refers to the use of sterile packaging materials after sterilization of mobile food filling packaging in a sterile environment. This type of packaging can be used for many foods:
Step 1: Milk
Generally, milk with a long storage life can be packaged completely without wormwood. It is sterilized at a temperature of 130-150℃ for 2 -- 6 seconds before sterile filling. The sterile milk, stored at room temperature (20-27℃) for a month, showed no microbial growth and no change in quality.
2. Citrus juice, apple juice and other drinks
The sterile filling method of fruit juice drinks is basically the same as that of milk. However, because the pH value of fruit juice is below 4.5, the objects of sterilization are yeast, mold and lactobacillus. The maximum heating temperature of the sterilization device is generally below 100℃. After several seconds of sterilization, it can be filled and packed into the container after cooling to 20℃.
The aseptic packing method of ketchup is to raise the ketchup to the specified temperature instantaneously through the injection heating method, wash it inside the pressure reducer, remove the excess water in the ketchup and make it cool. The temperature for rapid sterilization is 90-95℃, and when it is cooled to 40℃, it can be filled into the packaging container after sterilization.
(2) semi-aseptic packaging
It refers to the packaging method that restraines the initial bacteria number of solid food that is difficult to be completely sterilized, such as sausage slices, bacon slices, mixed sausage of pig and beef, cake, etc., and uses sterile materials to package in a sterile room, and then refrigerates and circulates.
Step 1: Cake
Cakes baked from a continuous oven are cooled in a sterile room, cut into a certain size in a cutting machine, and then inflated and packed. Put it into the outer packing container in the outer packing room. The temperature in the outer packing room should be adjusted at 15 ~ 18℃.
In this way, the cake packed with K/PET/PE packaging materials in a sterile room can be stored for 25 days at a temperature of 30℃ and a relative humidity of 95%, if carbon dioxide gas is injected. 2. Processed meat After being vacuum-packed in a sterile state, processed meat is usually not heated, so the food tastes good. Recently there has been the emergence of sterile state inflatable packaging. This packaging method is to be distributed at low temperatures.
2. Home-cooked food
In order to improve the preservation of salads in foreign countries, aseptic packaging technology is also used, that is, the salad is made in aseptic state as far as possible, and aseptic packaging is carried out in aseptic room.