Isolation, identification and classification of coliforms from aquatic products in Zhanjiang

Aquatic products are prone to be contaminated by coliforms. In order to better control the microbial safety of aquatic products, isolation, identification and classification of coliforms from aquatic products in Zhanjiang were conducted. 55 aquatic samples with coliforms in Zhanjiang from Nov 2012 to Jan 2013 were collected and 65 strains of coliforms were isolated and identified by biochemical test and VITEK2 system, 63 strains were confirmed to be 8 species of coliforms, in which 24 strains belonged to Citrobacter freundii, 14 strains belonged to Escherichia coli, 13 strains belonged to Enterobacter cloacae, 7 strains belonged to Klebsiella pneumoniae and 5 strains belonged to other types of bacteria, accounting for 38.10%, 22.22%, 20.63%, 11.11% and 7.93% of the totally isolated strains, respectively, and 2 strains were unknown. Accordingly, C. freundii was found in all kinds of those samples, and the frozen tilapia fillet mainly contained C. freundii and E. cloacae, totally taking 77.27% of the bacteria found, while the fresh white shrimp and shellfish were mainly contaminated by C. freundii and E.coli, totally taking 65.79% of the bacteria found, while E. coli was not found in all of the frozen aquatic products. And more species of coliforms were found in raw aquatic products than those in processed aquatic products.