Justification of the microbiological standard for the safety of raw milk of extra grade according to the content of Staphylococcus aureus

Abstract

Goal. To determine the permissible content of Staphylococcus aureus (Staphylococcus aureus) in raw milk at various stages of primary processing, storage, and transportation to establish its microbiological standard in raw milk as an indicator of safety. Methods. Sampling and their research were carried out under DSTU ISO 707:2002, DSTU 7357:2013, and DSTU 7452:2013. Isolation of staphylococci was carried out on meat-peptone agar with 5% bovine blood and 5% sodium chloride; identification of pure cultures — using the STAPHY-test 16 test system. Results. It was established that Staphylococcus bacteria were always present on the skin of the udders of healthy cows, and Staphylococcus aureus was isolated in 25.3% of animals. Regardless of the sanitary condition of the equipment, contamination of raw milk with S. aureus microorganisms occurred, so it was practically impossible to obtain milk that did not contain Staphylococcus aureus. Adhering to modern production conditions and ensuring excellent cleanliness of milking equipment, it is possible to obtain raw, freshly yielded milk with a content of S. aureus microorganisms up to 100 CFU/cm3. The presence of more Staphylococcus aureus in it will indicate the ineffectiveness of anti-mastitis measures, pre-milking treatment of cows’ udder, or sanitary treatment of milking equipment. It was found that during the collection of fresh milk and its cooling to 6°C, the amount of S. aureus increased by 2.5 times, and during transportation from the farm to the processing plant — by 1.5 times and reached 300–500 CFU/cm3. Conclusions. The standard for the content of Sta­-phylococcus aureus in raw milk is scientifically substantiated, namely less than 500 CFU in 1 cm3, and it meets the requirements of the EU countries.