Yogurt not only tastes good, it's also healthy. It is an important source of protein, provides the body with calcium, and aids digestion. So it's no surprise that the tasty dairy product is so popular. To guarantee a suitable shelf life for yogurt and to make sure that it meets strict hygiene standards, the cups are disinfected with hydrogen peroxide just before they are filled.
Bulk milk tankers pull into the production site of the Zott dairy company in Mertingen in the German state of Bavaria. They come directly from the farms and their compartments are filled with fresh raw milk that will now be pumped into the dairy's large milk tanks. "Each year, we process about 950 million kilograms of milk into yogurt and other dairy products," explains Martin Schweihofer, head of Technology & Facility Management at Zott. And, since dairy products are regarded as healthy, demand is rising continuously.
Yogurt is especially popular in Europe. When it comes to per capita consumption, the French are the European champions, with 17.8 kilograms per year. Germans consume about 13.9 kilograms and in Ireland, people eat roughly 11.5 kilograms of yogurt each year on average. To ensure that consumers can enjoy the tasty dairy products safely, during the production process they are controlled thoroughly in accordance with strict hygiene standards. This is because dairy products are particularly susceptible to germs.
Consequently, in the final production stage, the process known in the industry as aseptic filling is state-of-the-art: Just before it is filled, the packaging is disinfected with hydrogen peroxide. In addition to the biocidal effect, it must also be very easy to remove the product from the packaging so that no residues remain. The hydrogen peroxide that Evonik has developed for this is ultra pure and, when subjected to heat, decomposes to oxygen and water, which makes it a very environmentally compatible product that is ideally suited for use in the food industry. As one of the world's biggest providers of hydrogen peroxide, Evonik has been supplying the product to the food industry since the 1960s. "The high bactericidal effect of hydrogen peroxide and its good environmental compatibility have contributed to the sweeping success of aseptic filling," says Friedhelm Brandner, who is responsible for technical service for active oxygen products at Evonik. During his regular visits to customers, like today in the Zott dairy company, he always walks through the production halls, where he checks the production process and provides safety training.
Many machines operate in the dairy and they are treated with OXTERIL® 350 BATH, a hydrogen peroxide that was especially developed for the food industry. "Depending on the product, the cups are disinfected either in an immersion bath or they are sprayed," explains Brandner.
Large rolls of brown-white patterned plastic films are stacked in the production hall. If you look closely, you see that it is the packaging for the creamy chocolate-hazelnut dessert "Zott Monte." However, the plastic film is first unwound from the roll and pulled into what is known as a thermoforming machine. Before the film is shaped into cups in the machine and filled with the tasty dessert, it is disinfected in a hot solution of OXTERIL® 350 BATH. "Residues of hydrogen peroxide are completely removed," explains Johann Baur from Zott's Quality Management Department.
In another hall we find the filling machines that are currently filling cups with different flavors of creamy yogurt at an incredible speed – flavors such as Amarena cherry, Bourbon vanilla, and orangemango. Hundreds of printed but still empty cups are drawn into the machine and treated with OXTERIL® 350 SPRAY that is applied through a nozzle. Only when the surplus hydrogen peroxide has been evaporated with sterile hot air in a screened filling area are the cups filled with yogurt and sealed hygienically.
"The safety of our food products is top priority for us," says Baur. "This is why we are very glad to have Evonik as a supplier, as we can always rely on the product quality and the service. Treatment with hydrogen peroxide and sterile filling are also important for the shelf life of the yogurt," explains Baur.
In many cases, Friedhelm Brander's work actually begins after he has visited a customer. If, for example, the dairy company plans to introduce a new product or a new seasonal flavor, it usually also requires a new pot design. "We then examine potential interactions between the new packaging and the hydrogen peroxide and, if necessary, provide advice regarding changes to the packaging material," says Brandner. "We continuously optimize our range of OXTERIL® 350 products in close collaboration with the machine manufacturers and the filling companies to ensure optimum erformance."
A truck carrying 33 pallets of yogurt leaves the site. The cups will soon be standing in the refrigerated shelves of German and European supermarkets. Consumers can have confidence that they can enjoy these high-quality dairy products with absolutely no concerns in terms of food safety.