Packaging of milk powder products: how to make the inner packaging safer
in recent years, with the development of science and technology, the types of dairy products have gradually increased, with a longer shelf life and more convenient to carry or drink, which is 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. 1. Pneumatic protection: the system can set the surface to be tightly sealed with a metal cover or contained in a plastic bottle. 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. The purified raw milk should be heated and sterilized in three forms: low temperature long-time sterilization, high temperature short-time sterilization and ultra-high temperature instantaneous sterilization. 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 used for chromatic printing of exquisite patterns
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 pound small packaging, and later mainly 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
in order to solve the problem of normal temperature preservation of milk, in addition to selecting packaging materials with good impermeability and strong light isolation, the key is to reduce or avoid the secondary pollution of milk during packaging. The emergence of aseptic filling technology solves this problem. After the milk is sterilized by the ultra-high temperature instantaneous sterilizer, it is directly filled by the sterile filling machine through the pipeline. The whole process is carried out in a sealed state. Aseptically filled sterilized milk is packed in bags (boxes) made of multilayer composite materials, which are composed of PE/PE/Al/PE/paper/PE, PE/ET/Al/PE/paper/PE. Using this kind of packaging material together with the automatic filling machine can be completed on the filling line, which can reduce the chance of pollution. Therefore, sterilized milk filled aseptically can be stored for half a year to one year at room temperature
packaging of milk powder products
there are many kinds of milk powder, which vary according to the composition of raw materials and the more harmonious and unified 1 processing methods and the types of auxiliary materials and additives, mainly including whole milk powder, skimmed milk powder, whey powder, prepared cheese, special prepared milk powder, etc. with the progress of science and technology, various types of milk powder continue to appear, such as instant milk powder, cream powder, ice cream powder, buttermilk powder, cheese powder, fat free desalted whey powder There are fat desalted whey powder and whey concentrate milk, etc
although there are many kinds of milk powder products, their common feature is that raw milk should be dried and finally made into powdery products at a low cost. Milk powder products have the characteristics of reducing the volume of products, reducing the quality, preserving nutrients, preserving resistance, convenient use and so on
because dairy products are rich in various nutrients such as protein and fat, such as the milk fat content of whole milk powder can reach about 26%, they are easy to change under the action of sunlight, chlorine, etc. In addition, due to the porous nature of milk powder particles, its surface area is large and its moisture absorption is strong. Once it is wetted, it will agglomerate and cause bacterial reproduction. When mixed with other items, if the air tightness of the package is not good, it is easy to absorb the odor of other items and affect its own odor. Milk powder and other products will decompose under UV irradiation. Therefore, full attention must be paid to the weighing of milk powder products, packaging operations and the types of packaging containers, mainly to prevent moisture, oxidation, prevent the proliferation of bacteria, and avoid UV radiation. The packaging room of the milk powder factory should take air humidity control and cooling measures. The room temperature is generally controlled at and the heat treatment method adopted to achieve these requirements. The air humidity should be less than 75%. Milk powder products requiring long-term preservation should be vacuum packed or nitrogen filled. The whole milk powder is best packed in a 500g iron can filled with nitrogen, and the storage period can reach 3-5 years
the packaging of milk powder packaged in metal cans generally adopts vacuum nitrogen filling packaging. Nitrogen filling packaging uses a semi-automatic or full-automatic vacuum nitrogen filling can sealing machine. After weighing and filling, it is pumped into vacuum to eliminate milk stools and air pollution in the tank, and then immediately filled with nitrogen with a purity of more than 99% for sealing. This is one of the best methods for sealing and packaging whole milk powder at present. The experiment shows that the flavor of the whole milk powder packed with nitrogen is basically unchanged after 9 months of storage at 24 ℃, while the flavor of the whole milk powder packed without nitrogen will change and the quality will decline significantly after 4 months of storage
the plastic bag is packed with 500g single-layer polyethylene film bag, which is cheaper than the bottle, has low labor intensity, and has a certain moisture-proof effect. However, it has a certain impact on the preservation of dairy products. The heat insulation performance is poor, and the milk powder is easy to deteriorate, which can only meet the needs of short-term storage. Moreover, the film is brittle and easy to break, which is easy to cause damage. Double layer laminated paper with a layer of polyethylene film sandwiched with a layer of aluminum foil or packed in a three-layer film bag and sealed with high-frequency electrothermal welding can basically avoid the infiltration of light, moisture and gas. Composite film packaging materials are widely used in milk powder packaging. Although the current cost is high, it is one of the promising packaging materials. At present, the three-layer composites used mainly include: k-coated hard paper/al/pe, bopp/al/pe, paper/pvdc/pe, etc
large package products are generally supplied to special users, such as export or food processing plants, which are used to make candy, bread, ice cream and other industrial raw materials. Canned products include 12, 5kg round cans and square cans. When bagging, polyethylene film can be used as the inner packaging, and three layers of kraft paper are used to cover the outside, which are divided into 12 kg, 5 kg and 25 kg
source of information: China Packaging News
this article is from the Internet. The copyright belongs to the original author, and it is only for everyone to share and learn. If the author believes that sensors, fixtures and accessories of different tonnage can be added as needed to complete one machine multi-purpose and infringement, please contact us, and we will delete it immediately after verification
LINK
Copyright © 2011 JIN SHI