In the present investigation, a multiplex PCR was standardised for the simultaneous detection of Y. enterocolitica, S. Typhimurium and S. Enteritidis. For that, a common enrichment protocol was developed for the simultaneous recovery of the organisms. Modified Tryptic Soy Yeast Extract Broth (TSBYE) at 370C for 16 h. was selected as an uniform enrichment protocol for the simultaneous enrichment of Y. enterocolitica, S. Typhimurium and S. Enteritidis. Multiplex PCR was standardised using primers ail, stm and sen for Y. enterocolitica, S. Typhimurium and S. Enteritidis respectively. The PCR technique could detect a concentration of up to 1 cfu/ g of Y. enterocolitica, S. Typhimurium and S. Enteritidis in mixed culture. The multiplex PCR standardised did not show any non-specific reaction with other competing organisms. A total of 210 samples from pigs were collected including 128 pork samples, 51 tongue samples and 31 tonsil samples from different retail outlets and slaughter houses at Thrissur and Eranakulam, Kerala, India. One sample of pork was positive for Y. enterocolitica and seven samples were positive for S. Enteritidis.
