MOLECULAR DETECTION OF ENTEROHAEMORRHAGIC Escherichia coli IN RAW MILK SAMPLES OF THRISSUR

The present investigation was undertaken to study the occurrence of Enterohaemorrhagic Escherichia coli (EHEC) in pooled and individual raw milk samples of milk co-operative societies belonging to Thrissur district. A total of 72 pooled and 230 individual raw milk samples were collected from six milk co-operative societies of Thrissur district, Kerala. Out of 72 pooled and 230 individual raw milk samples examined, E. coli was isolated from 27.78 and 26.52 per cent of samples, respectively. The isolation rate of EHEC was found to be 11.11 and 8.26 per cent for pooled and individual raw milk samples, respectively. For molecular confirmation of the isolates, a multiplex PCR assay targeting stx 1, stx 2, eae A and hly A genes of EHEC was standardised. The virulence genes encoding stx 1, stx 2, eae A and hly A were identified in 33.33, 88.89, 11.11 and 33.33 per cent of isolates, respectively. The results of the study suggest that raw milk could be an important source for EHEC infection and poses a high public health risk