Abstract:

In the polymerase chain reaction (PCR) detection procedure of E. coli in milk sample, DNA template was extracted from the milk sample which was contaminated by E. coli artificially after 8-h enrichment or directly, and primer was designed from the conservative region of E. coli alanine racemase gene (alr). After PCR amplification, agarose gel electrophoresis was conducted. The results showed that the detection limits of E. coli in both whole and skim milk samples with and without 8-h enrichment of E. coli are 1 CFU/ml and 104 CFU/ml respectively. Compared with the method of GB/T 4789.3—2003, PCR detection method has higher sensitivity and accuracy and is timesaving.

Key words: E. coli, PCR