Sterilization

It is milk that has preserved its natural properties and does not contain microorganisms. There are some pre-processes that need to be done before starting sterilization. These are cleaning, homogenization and preheating processes. In the cleaning phase, raw milk is passed through centrifuges ( clarifier separators ) and is purified from dirty materials and some bacterias. In the homogenization process, it is ensured that the milk fat is completely mixed with the milk.In the pre-heating process, a short-term heat treatment at 120 ºC is applied and the vegetative and spore-formed microorganisms are killed by cooling them down to 70-80 ºC.

Sterilization of milk in bottles and cans

Empty bottles come to the filling section on a moving belt, milk is filled and their mouths are closed.On the moving belt, milk bottles or boxes go through four stages.In the first stage, preheating is done.At this stage, the temperature is 95-97 ºC.The second stage is the sterilization stage.At this stage, sterilization is performed at 140 ºC for 20 minutes.In the third stage, a cooling process is carried out up to 90 ºC.In the final stage, the temperature is reduced to 45 ºC and the sterilization process is completed.Since the natural qualities of milk are changed in this method, it is a very undesirable method for the consumer and the producer.In addition, this method has not become widespread in our country due to the slow progress of the process and the lack of continuity.

Sterilization by U.H.T (ultra high temperature) method

In order to produce a commercially sterile product that can be stored at room temperature, it destroys all microorganisms and their spores that will cause deterioration under normal storage conditions, at a minimum of 135 ºC in 1 second, in an appropriate time-temperature combination. It is a short-term, continuous flow heat treatment at temperature. The process is carried out with modern equipment that works continuously. In this process, the milk is taken to the specified temperature in a few seconds and 1.4.because it is held for about a second and then cooled very quickly. There is no change in taste, smell and color. Vegetative forms and spores of pathogens and other microorganisms are almost completely destroyed. As with pasteurization of processed milk with this method, cold storage. It is possible to last for six months without the need for (preservation) of it. One of its most important advantages is that it is packaged under fully aseptic conditions and without causing any contamination in packaging machines immediately after heat treatment.It provides ease of transportation to distant places and can be found everywhere.

Sterilization by U.H.T method

• U.H.T sterilization by direct method: With milk preheating 78It is heated to ºC.Here, the milk passed to the superizer is kept at 150 ºC for 2-3 seconds with steam, cooled to 80 ºC and packaged under aseptic conditions.

• U.H.T sterilization with indirect method: 85 with milk preheatingAfter being heated to ºC, it is kept at 135 ºC for 2-3 seconds with steam,It is cooled and packaged under aseptic conditions.

• Electrical sterilization: In recent years, sterilization of milkelectrical systems are also used.