Author(s): Arthur TM, Keen JE, Bosilevac JM, BrichtaHarhay DM, Kalchayanand N, , Arthur TM, Keen JE, Bosilevac JM, BrichtaHarhay DM, Kalchayanand N,
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Abstract The objectives of the study described here were (i) to investigate the dynamics of Escherichia coli O157:H7 fecal and hide prevalence over a 9-month period in a feedlot setting and (ii) to determine how animals shedding E. coli O157:H7 at high levels affect the prevalence and levels of E. coli O157:H7 on the hides of other animals in the same pen. Cattle (n = 319) were distributed in 10 adjacent pens, and fecal and hide levels of E. coli O157:H7 were monitored. When the fecal pen prevalence exceeded 20\%, the hide pen prevalence was usually (25 of 27 pens) greater than 80\%. Sixteen of 19 (84.2\%) supershedder (>10(4) CFU/g) pens had a fecal prevalence greater than 20\%. Significant associations with hide and high-level hide (>/=40 CFU/100 cm(2)) contamination were identified for (i) a fecal prevalence greater than 20\%, (ii) the presence of one or more high-density shedders (>/=200 CFU/g) in a pen, and (iii) the presence of one or more supershedders in a pen. The results presented here suggest that the E. coli O157:H7 fecal prevalence should be reduced below 20\% and the levels of shedding should be kept below 200 CFU/g to minimize the contamination of cattle hides. Also, large and unpredictable fluctuations within and between pens in both fecal and hide prevalence of E. coli O157:H7 were detected and should be used as a guide when preharvest studies, particularly preharvest intervention studies, are designed.
This article was published in Appl Environ Microbiol
and referenced in Journal of Food: Microbiology, Safety & Hygiene