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Description
Enterobacteriaceae have been established as indicators of microbiological quality and hygiene in food processing and are therefore an important factor in ensuring microbiological quality of milk. The aim of this study was to evaluate the effect of two commercial probiotic preparations, Diastop® Probio, containing four types of lactic acid bacteria: Lactobacillus acidophilus, Streptococcus thermophilus, Bifidobacterium, and Lactobacillus delbrueckii, and NBL Probiotic ATP, containing: Lactobacillus casei, L. rhamnosus, L. plantarum and Bifidobacterium lactis, on the microbiological quality and safety of raw cow’s milk. The initial microbial load in the milk was assessed, and the probiotic preparations were subsequently applied separately on samples of milk and incubated at 42 °C for four days. Changes in total mesophilic aerobic microorganisms and Enterobacteriaceae were assessed during the incubation period through the use of Plate Count Agar (PCA) and Violet Red Bile Glucose Agar (VRBGA) medium plates correspondingly. The initial sample of milk contained 7.6 × 10⁴ CFU/mL Enterobacteriaceae and 6.0 × 10⁶ CFU/mL mesophilic aerobic microorganisms. After probiotic treatment, Enterobacteriaceae progressively decreased, with no detectable growth on VRBGA at the higher dilutions by the third day and at the lower dilutions by the fourth day. In turn, the number of mesophilic aerobic microorganisms increased during the incubation period, and it could be associated with the growth of probiotic microorganisms. Overall, the tested probiotic preparations showed potential for lowering Enterobacteriaceae counts and may enhance the microbiological quality of raw cow milk.