In China liquid milk market in 2002, bagged milk accounted for 45% of the market share, paper brick milk accounted for 25% of the market share, plastic bottles accounted for 17%, plastic cups accounted for 7%, glass bottles accounted for 5.5%, and other packaging such as tin cans accounted for 0.5%. This variety of packaging forms is largely determined by the different preferences of consumers.
But it is inconvenient to drink and carry, and the bag packaging is economical and practical. And plastic materials are not environmentally friendly; Aseptic processing technology of paper brick packaging forms, easy to carry, advanced sterilization technology, good quality, long shelf life, but the interest in aseptic processing packaging technology of milk will be higher.
High-grade milk packaging represented by Tetra Pak is growing rapidly in the south. In the south and central and western regions, economical milk packaging is the main method. Low-grade packaging represented by plastic bags accounts for 70% of the whole liquid milk market in this region, but aseptic pillows and plastic bags produced by Tetra Pak are growing rapidly in the southern market, indicating that high-quality packaging is increasingly welcomed by the market.
At present, this technology has been widely used in fresh milk packaging in developed countries, and the fresh milk packed in tetra pak pillow adopts ultra-high temperature instant sterilization composite packaging technology. The shelf life of fresh milk can reach 45 days at room temperature. The technology is to instantly sterilize high-quality fresh milk at ultra-high temperature as high as 135 degrees, and then fill and seal it with six layers of paper, aluminum and plastic composite aseptic packaging materials under sealed aseptic conditions. All germs and microorganisms that affect the deterioration of milk will not come into contact with it, and milk can be stored at room temperature for more than one month without preservatives.
Suitable for filling high-grade products with high nutritional value and fresh taste, such as fresh milk, colored milk, yogurt and lactic acid bacteria drinks. The words "2-4℃ warranty 10 day" are written on the package of the roof box, and the roof box is beautifully printed. Compared with Tetra Pak, the short shelf life limits long-distance transportation. However, because the roof box is paper-packed, the interest is low. 1994, international paper took the lead in introducing roof box packaging into China market. Shanghai Guangming, Beijing Sanyuan, Inner Mongolia Yili, Hangzhou Jinding and other important domestic dairy producers have successively cooperated with international paper industry to open up the roof box packaging market. In recent years, based on the improvement of domestic cold chain system from time to time, the sales volume of roof box fresh-keeping packaging products in the market has been greatly improved.
Pasteurized milk accounts for 60%, which is currently in China liquid milk products. Ultra-high temperature sterilized milk accounts for 2 1. 1%, and cheese accounts for 19%. Among them, ultra-high temperature sterilized milk is obviously on the rise, mainly because of its long shelf life, diversified packaging and convenient storage and carrying.
The disinfection time is moderate, and the milk in glass bottles, plastic bags and roof cartons commonly used in the market has been pasteurized. It can effectively control the number of bacteria within 30,000 per milliliter stipulated by the state, and keep the taste of milk. Pasteurized milk (bagged/house-shaped) is also called pasteurized milk. It needs to be sterilized at about 89℃ for a few seconds and then stored at low temperature. The shelf life is usually 1 day to 7 days. When the storage temperature exceeds 4℃, the bacteria in milk can still reproduce, so it cannot be temporarily stored at room temperature.
Judging from the regional distribution of milk sources in China. There are few milk sources in southern and coastal economically developed areas. If there is no instantaneous ultra-high temperature sterilization technology (UHT is limited by the short shelf life of milk, it is difficult for areas with high-quality milk sources to transport milk to markets with large milk consumption in the south.
At present, this technology has been widely used in fresh milk processing in developed countries: milk is heated above 135℃, and UHT technology is used to solve the problem of transportation, storage and preservation of liquid milk. After only a few seconds, it was quickly cooled to normal temperature, and then sealed with 6 layers of paper, aluminum and plastic composite sterile materials under sealed aseptic conditions.
However, it is a contradiction to improve the shelf life and insist on the door feeling and appropriate cost of liquid dairy products. The emergence of aseptic blow-molding bottles and aseptic filling technology and the progress of liquid dairy packaging technology are of great significance to large dairy production groups. Let it find its balance. Blow-molded aseptic plastic bottle is a kind of plastic bottle with completely aseptic interior and no loose particles such as yeast. Because the bottle mouth is sealed, it is always sterile during storage and transportation to the aseptic filling machine. It is only necessary to sterilize the outside of the bottle with sterile liquid before filling, so as to ensure that the whole processing process of reopening, filling and secondary sealing of the bottle is carried out in a sterile state.
The middle layer is black, and the bottle body of aseptic blow molding bottle for liquid dairy products is usually made of 3 or 6 layers of HDPE. The inner and outer layers of the three-layer bottle are white. Play a role in resisting ultraviolet rays. The shelf life of this product is 3 months, and there is no need for refrigeration. The shelf life of the product can reach 6 ~ 9 months by adding the EVOH barrier layer into the 6-layer bottle.