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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Meat Safety and Quality » Research » Publications at this Location » Publication #302915
Title: Distribution of Escherichia coli passaged through processing equipment during ground beef production using inoculated trimmings

Author
item KOOHMARAIE, MOHAMMAD - Institute Of Environmental Health Laboratories And Consulting Group
item DE LA ZERDA, MICHAEL - Institute Of Environmental Health Laboratories And Consulting Group
item Bosilevac, Joseph - Mick
item ALI MOHSENI, MOTLAGH - American Foods Group, Llc
item SAMADPOUR, MANSOUR - Institute Of Environmental Health Laboratories And Consulting Group

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/8/2014
Publication Date: 2/1/2015
Citation: Koohmaraie, M., De La Zerda, M., Bosilevac, J.M., Ali Mohseni, M., Samadpour, M. 2015. Distribution of Escherichia coli passage through processing equipment during ground beef production using inoculated trimmings. Journal of Food Protection. 78(2):273-280.

Interpretive Summary: When raw ground beef is found to be contaminated by Escherichia coli O157:H7 the ground beef made immediately before and after the positive sample are discarded or diverted to cooking. However, there is little data to support decisions on how much product must be diverted. Therefore, at three different commercial ground beef processing establishments an experiment was performed to track a green fluorescent protein (GFP) expressing strain of E. coli through production and packaging or re-packaging. At each location the GFP E. coli could not be detected after 2,650 lb (1,202 Kg), 3,750 lb (1,701 Kg) and 911 lb (413Kg) of production respectively. The differences were due to the types of ground beef producing and packaging equipment used. The GFP strain could not be detected afterwards in any residual meat or fat collected from the equipment used in the three trials. Results demonstrate that the current industry practice is acceptable as long as each ground beef producer has performed a study such as this to establish lot breaks and sampling protocols.

Technical Abstract: The contamination of raw ground beef by Escherichia coli O157:H7 is not only a public health issue but also an economic concern to meat producers. When E. coli O157:H7 is detected in ground beef, products made immediately before and after the positive sample are discarded or diverted to lethality treatment. However, there is little data to base decisions on how much product must be diverted. Therefore, at two different commercial ground beef processing establishments, five 2,000 lb (907 Kg) combo-bins of beef trimmings were processed into 10 lb (4.54 Kg) chubs of raw ground beef, wherein the second combo of meat was contaminated with a green fluorescent protein (GFP) expressing strain of E. coli. In addition, ground beef chubs from one of the grinding establishments were shipped to a third establishment where they were mechanically split and repackaged into 3 lb (1.36 Kg) loaves in trays. The GFP E. coli was tracked through the production of 10 lb (4.54 Kg) chubs and the strain could not be detected by PCR or direct plating after 2,650 lb (1,202 Kg) and 3,750 lb (1,701 Kg) of production following the contaminated combo at each establishment respectively. Three lb (1.36 Kg) loafs were no longer positive after 911 lb (413Kg) of production. The GFP strain could not be detected post-processing in any residual meat or fat collected from the equipment used in the three trials. Our results demonstrate differences in the kinetic flow of E. coli on beef trim through various commercial equipment and that each establishment needs to consider this data when establishing lot breaks and process sampling protocols to monitor production. Furthermore, this study lends support for the current beef industry practice of subjecting to lethality treatment any ground beef products produced from a lot with a positive E. coli O157:H7 test and the ground beef products produced from the lots before and after the positive lot.