In methylene blue reduction tests, methylene blue becomes blue when added to milk. However, if there is bacteriological activity in milk, this time it turns color white.

Almost all of the microorganisms present in milk affect the oxidation potential of the milk to such a degree that it changes the color of dyes such as methylene blue or resazurine. The methylene blue dye solution added to the tested milk is reduced as a result of the activity of the microorganisms in the milk and the blue color disappears. In addition, the leukocyte count of the milk, the concentration of the dye, the temperature and the residence time in the light affect the reduction event.

If the reduction time is higher than 5 during the tests, then the milk quality is good. The approximate number of bacteria detected at this time is 0,5 million / ml and less. But if the reduction time is less than half an hour, the milk quality is very poor. The approximate number of bacteria detected at this time is 20 million / ml and more.

Briefly, methylene blue tests are performed to obtain information about the number of bacteria in raw milk. If a certain amount of milk is mixed with a certain amount of methylene blue, which is a colorant, and kept at a temperature of about 40, the living bacteria in the milk reduce the methylene blue and cause the milk to become colorless.

From the moment of milking, milk is contaminated by many microorganisms depending on the ambient conditions. These microorganisms break down the components of milk in a short time and the toxins they produce are harmful to humans. Therefore, the quality and reliability of dairy products depends primarily on the quality of raw milk.

Determination of methylene blue in milk is carried out in authorized laboratories within the scope of chemical tests. In these studies, the standards published by domestic and foreign organizations and the test methods and test criteria accepted worldwide are complied with. With these systematic and scientific studies carried out in laboratories, more reliable and unbiased service is provided.