Contamination Rate of Bovine Raw Milk with Yersinia enterocolitica Biotypes in the Northeast of Iran

Yersiniosis is an important foodborne zoonotic disease worldwide. Gastroenteritis and septicemia are the primary forms of yersiniosis. Yersinia enterocolitica is a causative organism, which is frequently isolated from foods such as milk. This study aimed to evaluate the contamination rate of bovine raw milk with Y. enterocolitica during January-July 2017 and the biotyping of the isolated organisms.

 In total, 100 bovine raw milk samples were collected from Mashhad, Iran. The samples were enriched in peptone sorbitol broth. After alkali treatment, the enriched samples were streaked onto cefsulodin-irgasan-novobiocin agar plates. Suspected colonies of Y. enterocolitica were tested by the amplification of the 16s rRNA gene to confirm the isolates as Y. enterocolitica. The confirmed isolates were biotyped using biochemical tests.

The results showed that 33% of the bovine raw milk samples were contaminated with Y. enterocolitica. Biotype 1A was predominant (26%), while the pathogenic biotypes 1B (6%) and 5 (1%) were also detected.

 According to the results, the isolation of pathogenic Y. enterocolitica from bovine raw milk is a public health hazard due to its presence in dairy products.