Premium
Characterization and Survival of Environmental Escherichia coli O26 Isolates in Ground Beef and Environmental Samples
Author(s) -
Palmer Christine E.,
Bratcher Christy L.,
Singh Manpreet,
Wang Luxin
Publication year - 2015
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12827
Subject(s) - virulence , escherichia coli , inoculation , biology , multiplex polymerase chain reaction , vtec , microbiology and biotechnology , polymerase chain reaction , feces , pathogenic escherichia coli , shiga toxin , veterinary medicine , gene , food science , medicine , biochemistry , immunology
In addition to Escherichia coli O157:H7, shiga toxin‐producing E. coli (STEC) O26 was added to the zero‐tolerance adulterant list together with other 5 non‐O157 STEC serogroups in 2012. Four farm O26 isolates were used in this study; they were obtained from a on‐farm survey study conducted in Alabama. The presence of 3 major pathogenic genes ( stx 1, stx 2, and eae A) was determined through multiplex polymerase chain reaction (PCR). Two major pathogenic gene profiles were observed: 3 of the farm isolates contain only the eae A gene whereas 1 farm isolate has both the eae A and the stx 1 genes. No significant difference was seen among the 4 farm isolates in the antibiotic resistance tests. To test their survival in ground beef and environmental samples, 2 inoculums were prepared and inoculated at various concentrations into samples of ground beef, bovine feces, bedding materials, and trough water. One inoculum was made of 3 farm isolates containing only the eae A gene and another inoculum contained the isolate with both the eae A and stx 1 genes. Inoculated beef samples were stored at 4 °C for 10 d and the inoculated environmental samples were stored at ambient temperature for 30 d. Results showed that virulence gene profiles do not have an impact on O26's ability to survive in ground beef and in environment ( P > 0.05). The inoculation levels, sample types as well as the storage times are the major factors that impact O26 survival ( P < 0.05).