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United States Department of Agriculture

Agricultural Research Service

Title: Prevalence of Escherichia Coli O157 and Levels of Aerobic Bacteria and Enterobacteriaceae Are Reduced When Hides Are Washed and Treated with Cetylpyridinium Chloride at a Commercial Beef Processing Plant

Authors
item Bosilevac, Joseph
item Arthur, Terrance
item Wheeler, Tommy
item Shackelford, Steven
item Rossman, Michelle - NCBA
item Reagan, James - NCBA
item Koohmaraie, Mohammad

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 29, 2003
Publication Date: April 20, 2004
Citation: Bosilevac, J.M., Arthur, T.M., Wheeler, T.L., Shackelford, S.D., Rossman, M., Reagan, J.O., Koohmaraie, M. 2004. Prevalence of Escherichia coli O157 and levels of aerobic bacteria and Enterobacteriaceae are reduced when hides are washed and treated with cetylpyridinium chloride at a commercial beef processing plant. Journal of Food Protection. 67(4):646-650.

Interpretive Summary: E. coli O157:H7 is a bacteria that can cause life threatening infections, especially in very young, very old, or immunocompromised people. In many cases, infections are caused by eating undercooked contaminated ground beef. E. coli O157:H7 is highly prevalent on the hides of beef cattle where it is naturally found. When the hide is removed during beef processing the bacteria can contaminate the carcass. This hide-to-carcass transfer can lead to contaminated beef and ground beef products. We investigated a method to reduce this contamination by washing and treating the hides of live cattle in pens outside a processing plant with an antiseptic that is commonly found in mouthwash. These experiments were performed outside the processing plant because treatments such as these have not yet been approved for use inside the processing plant. The water wash and treatment with the antiseptic, cetylpyridinium chloride (CPC), reduced aerobic plate counts (APC) and Enterobacteriaceae counts (EBC), which are measures of two groups of bacteria that are indicators of overall cleanliness. APC on carcasses of treated cattle were reduced by 95% compared to those of untreated cattle. Likewise, EBC on treated cattle were also reduced 90% compared to control cattle. A specific reduction of E. coli O157 present on hides and carcasses was also observed following the wash and treatment with CPC. The prevalence of E. coli O157 on hides was reduced from 56.4% to 33.8% and the prevalence on pre-evisceration carcasses was reduced from 22.7% to 2.9%. These results indicate that a water wash and CPC treatment can effectively reduce hide-to-carcass transfer and contamination and should be further evaluated for implementation as a processing step after stunning and before hide removal inside the processing plant.

Technical Abstract: The objective of this experiment was to further test the potential of cetylpyridinium chloride (CPC) as a hide intervention by applying the treatment to cattle in the holding pens of the processing plant immediately before stunning. Over two processing days, 149 control and 139 treated cattle were tested. Control cattle were processed in the normal manner. Treated cattle were pre-washed with water the day before harvest. Immediately before stunning, treated cattle were sprayed twice with 1% CPC, first for 3 min then for 1 min. Hides and pre-evisceration carcasses were sampled to determine aerobic plate counts (APC), Enterobacteriaceae counts (EBC) and Escherichia coli (E. coli) O157 prevalence. The CPC treatment reduced the prevalence of E. coli O157 on hides from 56.4% to 33.8% and the prevalence on pre-evisceration carcasses from 22.7% to 2.9%. The CPC treatment decreased APC from 4.9 log10 CFU/100 cm**2 to 3.4 log10 CFU/100 cm**2 and EBC from 3.1 log10 CFU/100 cm**2 to 2.0 log10 CFU/100 cm**2 on pre-evisceration carcasses. The CPC treatment of hides did not result in any detectable CPC contamination of the chilled carcasses. These data indicate a 1% CPC treatment preceded by a water wash was capable of reducing hide prevalence of E. coli O157 from as high as 80% to less than 50%, resulting in pre-evisceration carcass prevalence of 5% or less. We conclude that water washing followed by an antimicrobial treatment, such as CPC, has great potential as an effective hide intervention step and should be further evaluated for implementation as a processing step after stunning and before hide removal.

Last Modified: 4/18/2014
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