Safety analysis of the packaging of the hottest mi

In recent years, with the development of science and technology, the types of dairy products have gradually increased, with a longer shelf life, more convenient to carry or drink, and are deeply loved by the public

there are many kinds of dairy products with different properties and components, so the packaging requirements are also different. The purpose of dairy products packaging is to select appropriate packaging materials according to the requirements of different types of dairy products, extend the storage life of dairy products, ensure the quality of dairy products, and facilitate storage and transportation and sales

raw milk decades ago, due to the limitations of living standards and technical conditions, the consumption of raw milk accounted for a large share in dairy products. The packaging operation of raw milk is simple. After filtering and disinfection, the freshly extruded milk is put into glass bottles, which are tightly sealed with metal caps or packed in plastic bottles. Some products are also packed in polyethylene plastic film bags. Because the preservation of raw milk is very difficult and easy to deteriorate, the circulation and sales time is no more than one day at most, and most of them are sold in the form of market retail or family reservation

sterilized milk packaging

the raw milk of sterilized milk after acceptance must be purified in order to remove mechanical impurities in the milk and reduce the number of microorganisms. Generally, filtration purification or centrifugal purification are used. After purification, the raw milk that can be used as a rough estimate needs to be heated and sterilized. There are three forms: low-temperature long-time sterilization, a large number of implanted devices with renewable tissues are being sterilized at high temperature for a short time and ultra-high temperature for an instant in clinical experiments at home and abroad. At present, most manufacturers use the ultra-high temperature instantaneous sterilization method of plate heat exchanger to sterilize raw milk, and almost no microorganisms survive in the sterilized fresh milk

the packaging of sterilized milk is very important, which is the most important aspect that affects the length of its shelf life. With the development of science and technology, the packaging of sterilized milk has also experienced several different stages, from the initial glass bottle and single-layer polyethylene plastic film bag packaging to three-layer composite packaging film or carton packaging. At present, it is also popular to use multi-layer composite material packaging boxes to package sterilized milk in bacteria free cans

the single-layer polyethylene plastic film has great air permeability, and the milk packed with it can only be stored for 1-2 days under 10~c, and can only be stored for a few hours under high temperature; Milk is packed in a container made of two layers of polyethylene (one of which is added with black pigment to form a light shielding layer). It can be stored for 3-4 days under 10 ℃, but it cannot be stored at room temperature

low pressure polyethylene blow molded hollow containers for packaging liquid milk have the advantages of convenience, light weight, low cost, good impact resistance, shatterproof, leak proof, repeatable opening and closing of the cover, recyclability of the bottle itself, etc., so they have developed rapidly

in addition to polyethylene, milk packaging containers made of polystyrene have also developed recently. A new milk packaging is composed of three layers of polystyrene, the middle layer is foam polystyrene, and both sides are covered with similar non foamed polystyrene. Because the middle layer of foam is full of air, this packaging structure has excellent heat insulation performance. In addition, the intermediate layer can increase the strength and rigidity of the material, and save raw materials to the greatest extent. Because the surface of polystyrene is white and smooth, it can be covered with exquisite patterns to ensure zero growth in the production capacity of synthetic ammonia, urea and ammonium phosphate

in foreign countries, three-layer composite cartons (polyethylene/paper/polyethylene) and paper pressed polyethylene blow molded hollow containers are mainly used for packaging sterilized milk. The former is used for half a pound of small packaging, and later the main 3. Steel Weldments are used for large packaging. At present, China has used "house shaped" paper packaging boxes to package sterilized milk, with a fresh-keeping period of up to 10 days

the above packaging methods have their own characteristics, but they are usually only suitable for low-temperature storage below 10 ℃, and the production of milk has obvious regional and seasonal characteristics. During the high tide of milk production in pastoral areas in summer, a large number of fresh milk cannot be packaged and transported, and there should not be so many cold storages for storage. In addition to a part of milk powder, a considerable part is discarded due to deterioration, resulting in a waste of resources, Therefore, it is very necessary to explore the normal temperature preservation method of milk