Progress and Discussion on the packaging technolog

Progress and discussion of liquid milk packaging technology

in recent years, the development of liquid milk in the dairy industry is particularly eye-catching, and has become a larger and faster growing variety. Liquid dairy products include pure fresh milk, ultra-high temperature sterilized milk and fruit flavored milk, etc. It is expected that China's dairy industry will develop rapidly in the next five years, with the growth rate of liquid milk reaching 30%. In addition to the successful operation of dairy production enterprises, packaging also plays a vital role, and dairy packaging is increasingly showing a trend of diversified development

the appearance of liquid milk packaging

liquid milk packaging mainly includes Tetra Pak and Kangmei box for ultra-high temperature sterilized milk packaging, Tetra Pak pillow for ultra-high temperature instant sterilized milk packaging, ridge bag for micro bacteria milk packaging, and plastic bags made of sterile composite film, such as bailibao. Glass bottles are mainly used for packaging pasteurized milk, flavored milk and yogurt. PP and PS cups are the main packaging containers of yogurt

according to statistics, in China's 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 7%, glass bottles 5.5%, and other packaging such as tin cans accounted for 0.5%. This rich and diverse packaging form is largely determined by the different preferences of consumers. Bag packaging has the advantages of economy and moderate price, but at the same time, it has obvious disadvantages such as inconvenient to drink, carry, old appearance, plastic material is not environmental friendly enough, etc; While the paper brick packaging with aseptic processing technology has the advantages of diverse forms, convenient carrying, advanced sterilization technology, good quality and long shelf life, the cost of milk with aseptic processing packaging technology will be relatively high, which also contributed to the formation of a new competitive pattern in the packaging market

in recent years, high-end milk packaging represented by Tetra Pak has grown rapidly in the south. While the northern and central and western regions are dominated by economical milk packaging, and plastic bag packaging accounts for 70% of the whole liquid milk market, but Tetra Pak's sterile pillows and sterile plastic bags are growing rapidly in the northern market, indicating that high-quality packaging is increasingly popular in the market. Using Tetra Pak, a box of 250ml liquid milk with a price of about 2.3 yuan accounts for 0.5 yuan. Tetra Pak pillow has a high cost performance ratio, and its cost price is 0.30 yuan. At present, this technology has been widely used in developed countries for fresh milk packaging, and the normal temperature shelf life of fresh milk can reach 45 days. In this technology, high-quality fresh milk is instantly sterilized at an ultra-high temperature of up to 135 ℃, and then filled and sealed with six layers of paper aluminum plastic composite sterile packaging materials under sealed sterile conditions. All bacteria and microorganisms that affect the deterioration of milk will not contact it. Milk can be stored at room temperature for more than a month without adding preservatives. The roof box is beautifully printed and suitable for filling high-end products such as fresh milk, fancy milk, yogurt and lactic acid bacteria drinks with high nutritional value and fresh taste, but it needs to be refrigerated and fresh-keeping, and the shelf life is also relatively short. The cost is low, about 0.48 yuan. This package is becoming more and more popular in big cities. The sales volume of the whole roof box milk market in 2002 (including yogurt and Lactobacillus drinks) increased by 30% compared with 2001, reaching 410000 tons, and it is expected that the sales volume in 2003 will reach 500000 tons. The packaging materials for roof boxes include both Tetra Pak and Japanese packaging paper, as well as packaging paper produced by domestic enterprises. Baili bag is a new low-cost packaging form, with a cost price of 0.12 ~ 0.13 yuan. Since the summer of 2002, this kind of aseptic composite membrane packaged dairy products has been sought after by the market. However, some insiders believe that Baili bag is only a transitional product, and the grade is still low. It will eventually be replaced by products such as roof boxes. Plastic bag packaging is a choice for small dairy production enterprises to reduce costs. The cost of plastic bags is only 0.04 yuan. However, due to its poor image, it will gradually be eliminated by the market. In addition, the "Wanrong bag" launched by Hunan Wanrong packaging company, combined with ultra-high temperature instantaneous sterilization and special aseptic filling equipment, can make the shelf life of milk at room temperature reach 30 days, 60 days and 90 days respectively, and the cost is about 0.05 ~ 0.07 yuan. However, this packaging method has not been generally accepted by the market. At present, the service life is long. China's large dairy enterprises use Tetra Pak or Kangmei box, but they have their own tricks in other packaging choices. For example, Mengniu relies on "Tetra Pak pillow" fresh milk to win the world, while Wandashan relies on "Baili bag" to enter the Shanghai market

the processing cycle of milk is short, the fresh-keeping requirements are high, and the market competition is increasingly fierce. Only by providing products with stable quality and constantly innovating technical support. As well as an in-depth understanding of the different habits of Chinese consumers, packaging suppliers can take the lead in the new competitive landscape. At present, pasteurized milk accounts for 60% of China's liquid dairy products, ultra-high temperature sterilized milk accounts for 21.1%, and the high activity of materials is comparable to PA66 cheese, accounting for 19%. Among them, ultra-high temperature sterilized milk showed an obvious upward trend, mainly due to the long shelf life of ultra-high temperature sterilized milk, diversified packaging, convenient storage and carrying. Pasteurization method is used for milk in glass bottles, plastic bags and roof cartons, which are common in the market. The disinfection time is moderate, which can effectively control the number of bacteria within 30000 per milliliter specified by the state, and maintain the taste of milk. Pasteurized milk is also called pasteurized milk. After sterilization at about 89 ℃ for several seconds, it needs to be stored at low temperature, and the shelf life is generally 1 ~ 7 days; When the storage temperature exceeds 4 ℃, the bacteria in milk can reproduce, so it cannot be stored for a long time at room temperature

many experts fully affirmed the contribution of UHT processing technology to the development of China's dairy market. The market share of sterilized milk is expanding, because UHT processing technology can alleviate the problem of uneven geographical distribution of milk sources in China

in terms of the regional distribution of milk sources in China, it is mainly concentrated in the northeast, North China and northwest. The South and coastal areas can mitigate its impact through vertical integration. There are few milk sources in economically developed areas. Without UHT (instant ultra high temperature sterilization) technology, it is difficult for regions with high-quality milk sources to transport milk to markets with large milk consumption in the South due to the short preservation period of milk

ultra high temperature instant sterilization technology (UHT) is used to solve the problem of difficult transportation, storage and preservation of liquid milk. At present, this technology has been widely used in developed countries for fresh milk processing: heat the milk to more than 135 ℃, keep it for only a few seconds, and then quickly drop to normal temperature, and then fill and seal it with six layers of paper aluminum plastic composite sterile materials under sealed sterile conditions. Some people worry that the nutrients contained in milk will be destroyed after high-temperature disinfection. In fact, there is no need to have such concerns. The bacteria in milk are all killed in an instant of high temperature, while most beneficial substances lose little in a short period of high temperature. It maximizes the nutritional composition of milk, kills bacteria, solves the problem of keeping fresh, and enables people to enjoy nutritious and delicious milk more conveniently and safely

the progress of liquid dairy packaging technology is of great significance to large dairy production groups, but improving the shelf life is a contradiction with maintaining the taste of liquid dairy products and maintaining appropriate costs. The emergence of sterile blow molding bottles and sterile filling technology has found a balance. Blow molded sterile plastic bottle is a kind of plastic bottle which is completely sterile inside and free of yeast and other loose particles. Because the bottle mouth is sealed, this kind of bottle will always remain sterile during storage and transportation to the sterile filling machine. It is only necessary to disinfect the outside of the bottle with sterile liquid before filling, so as to ensure that the whole processing process, such as re opening, filling and secondary sealing, is carried out in a sterile state

sterile blow molded bottles for liquid dairy products are usually made of 3 or 6 layers of HDPE. Technology's multi-layer coextrusion technology was originally used to solve waste leftover materials, mainly to reduce the use of raw materials and recycle 10% - 30% of the materials in each container, but it has been widely used in the manufacture of blow molding bottles of dairy products. The inner and outer layers of the 3-layer bottle are white, and the middle layer is black, which plays the role of UV resistance. The shelf life of the product is 3 months without refrigeration. EVOH barrier layer is added to the 6-layer bottle, and the shelf life of the product can reach 6 ~ 9 months

in June, 2003, skanemjerier dairy company of Sweden launched a new product packaging with a capacity of 2 liters blow molding packaging bottle to the market. The packaging bottle is made of a synthetic resin called eco lean, calcium carbonate higher than 40% and high-density polyethylene. The reason why this bottle is considered new is not only that the petrochemical raw materials it uses are less than 40%, but also that the additives it uses make it have the characteristics of fast cooling speed and enhanced hardness, which is different from most of the packaging of dairy products in the past. This new environmentally friendly resin material is not only approved for food packaging in Sweden, but also recognized in the European Union. It is reported that the eco lean packaging bottle adopted by the company will not be able to provide sufficient protection for the screen and replace the original dairy packaging bottle

source: sugar and Wine News