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Microwave-pasteurization of milk and cream
Our research team has studied a new method for milk and cream pasteurization using the energy of microwaves. The thermal treatment of milk must ensure, in a proportion of 99.9%, the destruction of the tuberculosis bacillus and of all the pathogens , as well as the common flora, such that the final product will respect the standard norms.The destruction of the tuberculosis bacillus requires a moderate thermal treatment (63°C), for 6 minutes, or a more intense one (72°C), for 8-12 sec.The pasteurization process is a thermal treatment consisting in heating milk, below 100°C, respecting a certain temperature-time ratio, ensuring the total removal of the pathogens and other microorganisms responsible for milk alteration.
Description of the process
Initially, the liquid is absorbed by a pump from the storage tank, with a specific flow rate, and is introduced in the heat exchanger for increasing the temperature to 54-57°C. Further, the liquid passes to the microwave chamber where the temperature will raise to 65-85°C (being the pasteurization temperature), then in the storage container and re-enters in the heat exchanger (ensuring the heating of the un-pasteurized liquid), it is cooled and it is collected in a proper vessel.
Results
The efficiency of the pasteurization process is influenced by several factors,like: temperature, irradiation factor – depending on the power of the microwave field, the retention period of milk inside this field, and was studied through several tests that were performed during this process: phosphates and microbiological tests (both classical and PETRIFILMS method).The efficiency reached its maximum value at 68°C. With respect to the presence oh the e coli, the efficiency of the microwave-pasteurization reached 100% for all the tested samples.