Co-Occurrence of Staphylococcus aureus and Ochratoxin A in Pasteurized Milk

Pathogens and mycotoxins are serious public health risks for humans and food safety in milk. This study concentrated on detecting Staphylococcus aureus and Ochratoxin A (OTA) in 210 pasteurized milk from ten urban Beijing districts to suggest the co-occurrence of S. aureus with toxin-producing genes and OTA in milk and the possible risk. S. aureus was identified by physiological and biochemical experiments and molecular biology experiments, and enterotoxin genes were identified by PCR. OTA was detected by LC-MS/MS. The study found 29 isolates of S. aureus, of which 17.24% had the sea gene encoding enterotoxin A. OTA was detected in 31 out of 120 samples and the maximum amount of detection was 18.8 mu g/kg. The results of this study indicate that when failing to guarantee the cold chain, the presence of S. aureus with enterotoxin genes in milk will present a risk to food safety. Furthermore, the high detection rates and levels of OTA in milk suggest that OTA is a hidden risk. The co-occurrence of S. aureus and OTA in milk is a food safety concern and there is a need to control the occurrence of these two biohazards in milk.