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Pasteurization allows you to slow down the growth of bacteria in food products (liquids) by heating the product to a certain temperature and subsequent cooling. The use of milk that has not passed pasteurization entails a higher risk of bacterial diseases. If you yourself keep dairy cows and goats, then pasteurization of milk at home will help you extend the shelf life of this product.
Pasteurization of milk involves the heat treatment of the drink. The heating process occurs up to 63-100 degrees Celsius (the exact temperature is determined by the selected method). The heat treatment method is named after the scientist Louis Pasteur from France, who managed to apply the technique to eliminate microorganisms in a liquid. The effectiveness of pasteurization is determined by the temperature and duration of milk exposure under a certain regime. Despite the lack of boiling, only pathogenic bacteria are eliminated. The optimal temperature regime of heat treatment preserves the beneficial milk microflora, the optimal characteristics of the drink (consistency, taste and smell).
For the successful destruction of pathogenic bacteria, it will be necessary to carry out the procedure correctly. They use sterile dishes and equipment without fail. If sterilization is carried out at an unsatisfactory level, there is a risk of up to one billion bacteria entering the drink with further active reproduction. As a result, the number of microbes will reach a million for every milliliter.
Pasteurization is recognized as an effective and inexpensive way of disinfecting the resulting drink for further fresh consumption or for the preparation of dairy and fermented milk products.
Varieties of pasteurization
Heat treatment of milk can be carried out in different modes. In each case, certain features of the procedure are taken into account.
- Long-term pasteurization is aimed at guaranteed suppression of pathogenic microorganisms. During the procedure, the properties of milk remain initial, but the vital activity of microbes is almost completely suppressed. The method is time consuming, therefore it is used in exceptional conditions. The pasteurization temperature is 65 degrees. The main difference is a long procedure, as this takes about half an hour. Traditionally, special large bathtubs with double walls are used. This method is considered one of the best, because its effectiveness is maximum (99%).
- Short-term pasteurization is carried out according to a more affordable scheme and involves the use of only hot water. The procedure is based on heat transfer. Milk is heated to 71 degrees, after which it is kept for 40 minutes. Efficiency reaches 98 percent, so this method is considered one of the best.
- With high-temperature pasteurization, milk is heated instantly without further exposure. The minimum temperature should be 85 degrees. This method resembles a short-term, but exposure is not expected. Heating is carried out not only using hot water, but also steam. Suppression of saprophytic microflora reaches 99.5 percent. Nowadays, this method, due to its specificity, is practically not used, but it can be effective for creams, which are later used for cooking butter.
- Ultra-high-temperature pasteurization involves two stages of the procedure. Initially, the temperature is increased at least to 70 degrees (but not more than 80). Then heated to 135-150 degrees with steam. In this mode, milk should be processed in less than one minute.
When carrying out any procedure, it is important to observe the correct parameters of the selected mode. It depends on how effective the selected types of pasteurization for milk processing will be.
Pasteurization of milk is aimed at eliminating pathogenic microbes. For this, the drink is subjected to a single heating. It is mandatory to observe a certain temperature regime and focus on the exposure time. Mesophilic bacteria die most quickly, but other microbes can remain active. If the liquid is stored at a temperature of less than +8 degrees, it is possible to get rid of pathogenic microflora, the product becomes high-quality and useful. The development of the remaining bacteria stops if the drink is properly stored.
The effectiveness of pasteurization depends on the microflora and the composition of the processed beverage. For this reason, the initial quality of the product is taken into account. In the future, storage conditions determine the final effectiveness of disinfection. If timely cooling does not occur, microorganisms continue to develop. To increase the efficiency of heat treatment, it is recommended to cool the milk obtained after milking to +3 degrees in order to eliminate most bacteria in a timely manner. Violation of the storage temperature activates the development of microflora, so the pasteurization technology becomes less effective and it will be difficult to improve microflora in the future.
To successfully carry out the procedure, disinfect equipment and inventory. If the preparation was unsatisfactory, the composition of the product will be worse due to the preservation of bacterial activity. An increase in the content of enterococci in milk after pasteurization indicates an unsuccessful heat treatment of the product, which remains dangerous.
Milk obtained by ultra-pasteurization can be stored without a refrigerator at room temperature for up to 4 months
Today, TEK hydrodynamic units are used for industrial heat treatment of products, which are also suitable for mixing, homogenizing (crushing fat globules into smaller ones), emulsification (obtaining emulsions by the method of separating a drop-liquid phase from supersaturated solutions, vapors). Manufacturers offer different models of equipment, so each company can choose the most suitable option. The possibility of shutting down the boiler plant and organizing procedures with minimal costs is assumed.
Proper heat treatment in the dairy industry eliminates pathogenic bacteria from the composition, improves taste characteristics. Clumps of macromolecular compounds are crushed by cavitation bubbles. At the same time, a reduction in energy consumption is guaranteed.
Modern installations are adjusted taking into account what the temperature of pasteurization should be and the further implementation of each stage, the exit of liquid from the installation. Careful process control increases the efficiency of the product heat treatment procedure. Modern pasteurizers (hydrodynamic units) heat the liquid in volume. A new class of pasteurizers eliminates sticking of the product.
In industry, pasteurizers with several sections (3, 4 or 5) are used. In this case, the main parameters of the installations are taken into account.
- The temperature of the heat treatment and cooling should be set before the start of the procedure. This is required to effectively disinfect the product and eliminate all undesirable bacteria from the composition.
- Raw milk must enter the regeneration (recovery) section for the first treatment. The optimal product temperature is 10-35 degrees.
- The separator is used to clean the incoming drink. In this case, heating occurs up to 37-45 degrees (the initial indicator is taken into account).
- Then the hot water temperature is set for pasteurization. The maximum allowable indicator is taken into account during pasteurization. In this case, the water should be hotter than milk.
- The next step is cooling. It is recommended to take into account the time of year and local conditions in order to properly configure the equipment used. Typically, milk should be colder than 9 degrees. For this, water (artesian, tap, ice) or brine can be used.
The pasteurizer, which is a plate heat exchanger, must be functional and reliable. Equipment setup should be carried out taking into account how milk is pasteurized in the production. This is required for careful monitoring of the heat treatment of milk.
Pasteurization at home
Heat treatment of milk is possible at home. To do this, use a steam bath or a modern multicooker with the presence of the "pasteurization" mode.
The best option is a long-term method, since it makes it easier to achieve the optimum temperature. It is advisable to heat a pot of water, where the packaging will be placed for the proper conduct of the event. The procedure can be compared to boiling a drink, but the quality of the product will remain almost the same with the elimination of pathogenic bacteria. Such pasteurization of milk at home is available for housewives and is effective.
For the procedure, you will need to use a pan with a lid, a functional thermometer, a slotted spoon or a wooden spoon (spatula).
- Fresh milk is poured into the pan and turn on the fire until it stops. It is recommended to stir the drink constantly. The appearance of lumps is extremely undesirable. The drink is heated to approximately 72 degrees, the maximum is 74-82. To control the temperature, a thermometer must be used.
- In the next step, the liquid is closed with a lid. Insist for half a minute.
- Then it is placed in a container with cold water and quickly cooled to at least 22-38 degrees.
According to this scheme, pasteurization of the product is carried out.
Nowadays, housewives can use modern multicookers with the appropriate mode. Now it is not necessary to carry out the usual procedure at home and carefully monitor everything. Using a slow cooker is a convenient and quick option. Milk is poured into a pan and set at a temperature of 60-80 degrees for about 20 minutes (homemade drink) or longer. If the purchased product is pasteurized, the duration is increased to 40 minutes. Then the multicooker is switched on to the Pasteurization mode. In the future, control is not needed, since at the end of time there will be a sound notification.
Pasteurizing milk is a one-time process. The procedure is not repeated, as the drink will lose some of its beneficial properties. Pasteurization will preserve the freshness of a healthy product for a long time.