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United States Department of Agriculture

Agricultural Research Service

Title: The Incidence of Escherichia Coli on Beef Carcasses and Its Association with Aerobic Mesophilic Plate Count Categories During the Slaughter Process

item Siragusa, Gregory
item Dorsa, Warren
item Cutter, Catherine
item Bennett, Gary
item Keen, James
item Koohmaraie, Mohammad

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 6, 1998
Publication Date: N/A

Interpretive Summary: The U.S. Food Safety and Inspection Service has stated that U.S. animal processing plants will be required to test for the bacterium, biotype I Escherichia coli (E. coli). Currently the test for biotype I E. coli takes several hours to complete--too long to enable processors to correct problems in processing as they occur. Techniques, such as bioluminescence, exist that allow processors to assess the generic bacterial contamination on beef carcasses. These techniques are much faster than culture tests for E. coli. This experiment was done to find the relationship between generic bacterial contamination on beef carcasses and the chances of finding biotype I E. coli. Based on a study of 590 beef carcass samples from two different plants, it was found that with increasing levels of generic bacteria, the likelihood of obtaining a sample that tested positive for E. coli increased. Therefore, using a rapid measure of generic bacteria as a means of monitoring the process could let the processor rectify problems that might contribute to fecal contamination.

Technical Abstract: An analysis of 590 pre-fabrication beef carcass samples taken in two processing plants demonstrated an association between the mesophilic aerobic plate count (APC) class and the incidence of obtaining an E. coli positive sample. Beef carcasses were sampled from two separate plants, one a fed cattle operation and the other a cow/bull plant. Samples were obtained by sponging and analyzed for APC and E. coli. Samples were classified into APC levels (0 < 2, >/= 2 and < 3, > 3 and < 4, >/= 4 log10 CFU/cm**2). The Chi square analysis of the resulting contingency table indicated a strong association between APC class and the incidence (presence or absence) of an E. coli positive sample. Of the APC class four samples (> 4 log10 CFU/cm**2), 96% were positive for the presence of E. coli whereas this percentage decreased in the lower APC classes decreasing to an E. coli incidence rate of 15% in APC class one (0 </= 2 log10 CFU/cm**2). The data highlights the potential for using near real time microbial monitors which indicate the APC for monitoring critical control points in the beef dressing process prior to the fabrication stage.

Last Modified: 4/22/2015
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