Plastic bottles for milk drinks

More and more milk drinks are now packaged in plastic bottles. The barrier properties of the bottles, the shading properties and the correct filling techniques are the key. The combination of "SIG Cooperras" and "SIG ASBOFILL" of SIG Beverage Machinery Division creates an ideal solution for the complex plastic bottle milk beverage packaging process.

In the packaging of dairy products in recent years, the share of plastic bottle packaging is increasing. The continued use of HDPE or PET bottles in flavored milk, mixed fruit milk, and health drinks demonstrates the acceptance of plastic bottle packaging in the dairy packaging market.

At present, the development of some popular milk drinks is quite rapid. Milk is a new type of functional beverage after adding juice, vitamins or other value-added additives. PET is becoming the new favorite of packaging when it comes to marketing these new beverages. PET's absolute transparency and high-glossy properties, such as glass, make packaging more appealing, highlighting the brand's value and distinctiveness and occupying a certain market for dairy products. In a highly competitive market environment, packaging has become a medium for delivering brand messages to consumers. Compared to other plastic packaging, PET has better barrier properties.

Figure 1 shows the growth rates of UHT milk drinks, such as UHT milk, UHT flavored milk, UHT cheese, UHT condensed milk, and other products such as soy milk and UHT-liquid dairy products (LDP). In Spain, which is one of the sources of data, the annual growth rate of only UHT milk drinks packaged in PET bottles exceeded 100%, from actual 4 million in 2003 to 74 million liters in 2007.

Dairy packaging requirements

In general, different milk drinks have very different requirements for the pre-processing, packaging and filling technology of the product itself. The table in Figure 2 shows the effect of pretreatment and filling technology on the shelf life of milk beverages.

In the cold chain conditions, the use of clean filling technology can achieve a standard shelf life of 10 days (or ESL milk with a shelf life of 21 days, fermented milk such as buttermilk, yogurt and health drinks). The protection function requirements of milk beverages on their packaging in their distribution, storage and sales are reduced as the temperature decreases, and the protection function mainly refers to the shelf life of the stability of milk drinks and the requirements for pre-treatment.

Sterile filling technology for non-cold chain low yoghurt products

UHT milk drinks, stored and sold at room temperature, are much more complicated. At this time, the requirements for the protection and filling technology of low-acid products are extremely harsh, because bacteria and microorganisms can easily survive and grow at room temperature in low-acid conditions.

For the filling of this product, the SIG ASBOFILL of SIG Beverage Machinery Division introduced the ABF series aseptic filling system. The aseptic technology used in the system is to use atomized hydrogen peroxide spray technology to sterilize the packaging. The device integrates bottle sterilizing, aseptic filling and aseptic capping or aluminum foil capping. The maximum filling capacity is 12,000 bottles/hour.

This filling system is now widely used in the aseptic filling of low-acid products such as UHT milk, milk beverages, milk coffee, flavored milk, yogurt, etc., and has achieved great commercial success. An important advantage of the SIG ASBOFILL ABF system is that the sterile field is very small, making the control and maintenance of the sterile field simple and safe. During the production operation of the equipment, the bottle is transported outside the sterile area, and only the bottle mouth is placed in the sterile area for aseptic filling. The process of sterilization is first by spraying a certain proportion of a mixture of atomized hydrogen peroxide and sterile air into the bottle, and maintaining a certain time in the bottle for oxidation; then, the bottle is sterilized by the oxidation of hydrogen peroxide. As a result, microorganisms in the bottle are removed. Finally, the atomized hydrogen peroxide residue in the bottle was brought out of the bottle by sterile hot air. In addition, according to the adjustment of different process parameters, such as temperature, hydrogen peroxide dosage and sterilization cycle, the sterilization decay rate of the equipment can be increased from LOG4 to LOG6.

How to solve the problem that PET bottles dairy products need to avoid light

For ESL milk and UHT milk, light blocking is critical. If there is no light blocking and the product is stored in a shiny supermarket freezer, milk will lose about half of the vitamin B2 nutrients within the first 12 hours. In addition, the light also destroys the protein components of the milk, giving the milk a metallic taste within 2-4 hours after the chemical reaction occurs, which is the so-called "light damaged taste."

For PET bottles of milk, light protection is especially important. In addition to the labeling of bottles, there is a more direct and effective light-proof packaging solution - SIG Cooperras's research found that there are many ways to improve the light barrier properties of PET packaging. Common methods are: increasing the content of titanium dioxide in PET resin and using white + black + white multilayer PET bottle packaging.

The low transmission rate shown in FIG. 4 indicates that the UHT milk packaged above can substantially block the light during its intended shelf life and extend its shelf life to 4 months. However, because the overall cost of this solution is higher than the current traditional multi-layer carton packaging (such as SIG Combibloc aseptic carton packaging), only high-end, high-priced dairy products can use it as its brand image.

Successful case of packaging dairy products with PET:

A successful example is the NOM company in Austria. In addition to the traditional packaging of milk beverages, the company also produces various types of novel milk beverage supply markets packaged in PET bottles, such as the famous “Festen” brand slimming milk series on the market. The product is a functional beverage jointly developed by the company and some well-known doctors and nutritionists. It is not only sold in Austria, but also in Germany's discount supermarket ALDI and other global chain discounts to supply the local market. Even China has its presence. .

NOM has used PET bottles to package most of its milk beverages for many years, using SIG Corpora's BLOMAX III Series blowers, a BLOMAX 10 and two BLOMAX 12. "The bottles that are blown out are light and easy to re-seal, making them ideal for many drinks, so our customers are very satisfied." Artur HARTLIEB, NOM's marketing director, said. In addition, he also introduced the situation of 125ml healthy milk beverages that have achieved great success in the market. Among them, the PET empty bottles used for packaging are only 8.5 grams in weight, which is the history of the production of the SIG Keborlas blower. The most lightweight bottle shape.

Another successful case came from the Nestluck Milchwerke Mittelelbe factory in Hanover and Berlin, which also used a large number of PET bottles to package its popular mixed-milk drinks, such as Latte macchiato, Cappuccino, Trink Fix SUPERSHAKER, and others. The aseptic filling of UHT milk drinks was performed on the SIG ASBOFILL ABF 710 Aseptic Filling Machine. The shelf life of the drink can be as long as 7 months.

Source: Packaging Machinery