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ESCHERICHIA COLI O157 IN IRISH FEEDLOT CATTLE: A LONGITUDINAL STUDY INVOLVING PREHARVEST AND HARVEST PHASES OF THE FOOD CHAIN |
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| Authors: | DONAL MINIHAN,PAUL WHYTE,MICHEÁ L O'MAHONY,TRACY CLEGG,JOHN D. COLLINS |
| Affiliation: | Food Hygiene Research Laboratory;Veterinary Epidemiology Investigation Unit Department of Large Animal Clinical Studies Faculty of Veterinary Medicine University College Dublin Belfield Dublin 4, Ireland;Central Research Veterinary Laboratory, Department of Agriculture and Food, Abbotstown, Castleknock, Dublin 15, Ireland. |
| Abstract: | The aim of this study was to investigate fecal shedding and transmission of E. coli O157 in cohorts of cattle within a feedlot, to assess subsequent contamination of carcasses with this pathogen and to identify risk factors associated with fecal shedding of E. coli O157. A cohort of 133 heifers housed infour adjacent pens was examined over a five month period, from entering the feedlot to slaughter. Individual rectal fecal samples and pen environmental samples were taken at monthly intervals. The entire outer and inner surfaces of a carcass side of each animal were swabbed immediately following slaughter. E. coli O157 was isolated from 136 (23%) of the 600 rectal fecal samples; 96% of which contained virulent markers. One hundred and sixty environmental samples were examined and E. coli O157 was isolated from 46 (29%), all of which contained virulent markers. E. coli O157 was not isolated from any of the dressed carcasses. The prevalence of E. coli O157 fecal shedding may be related to the pen and E. coli O157 contamination of the pen floor feces, water trough and feed. E. coli O157 should be considered as a pathogen shed in the feces of a substantial proportion of feedlot cattle. However, with good hygienic practice at harvest, a very low level of this pathogen can be achieved on dressed carcasses. |
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