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United States Department of Agriculture

Agricultural Research Service

Title: Inactivation of non-O157:H7 Shiga toxin-producing Escherichia coli (STEC) in frozen ground beef patties

item Luchansky, John
item Porto-fett, Anna
item Shoyer, Brad
item Call, Jeff
item Chen, Vivian
item Kause, Janell
item Eblen, Denise
item Cook, Victor
item Mohr, Tim
item Esteban, Emelio
item Bauer, Nathan

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/2/2011
Publication Date: 8/1/2011
Citation: Luchansky, J.B., Porto-Fett, A., Shoyer, B.A., Call, J., Chen, V., Kause, J., Eblen, D., Cook, V., Mohr, T., Esteban, E., Bauer, N. 2011. Inactivation of non-O157:H7 Shiga toxin-producing Escherichia coli (STEC) in frozen ground beef patties. IAFP Meeting, July 31-August 3, 2011, Milwaukee, Wisconsin., Poster No.1-55. p. 77.

Interpretive Summary:

Technical Abstract: A cluster of illnesses linked to contamination of ground beef with an E. coli serotype O26 strain, and the subsequent recall, reinforces the need for additional research on control of STEC in beef. Ground beef (percent lean:fat = 70:30 and 93:7) was inoculated with about 7.0 log CFU/g of a serotype O26, O45, O103:H2, O121, O145:HNM, and O111:H7 cocktail of STEC. Ground beef patties (ca. 300 g, ca 2.54 cm thick) were formed, stored at 4 degC for 18 hours (i.e., refrigerated) or at -20 degC for 21 days (i.e., frozen), and then cooked on either an open flame gas grill or on an electric clam-shell grill to target internal temperatures of either 60.0 deg, 65.5 deg, 71.1 deg, or 76.6 deg C. Regardless of the level of fat or type of grill, cooking refrigerated patties to 71.1 deg or 76.6 deg C resulted in a > 6.2 log CFU/g decrease in STEC, with decreases of 5.7 to 6.4 and 3.2 to 5.1 log CFU/g at 60.0 deg and 65.5 deg C, respectively. When frozen patties were cooked to 65.5 deg, 71.1 deg, or 76.6 deg C, regardless of the fat level or type of grill, pathogen numbers decreased by 4.7 to 6.0 log CFU/g, with a decrease of 2.5 to 4.4 log CFU/g after cooking to 60.0 deg C. These data confirm that cooking refrigerated or frozen ground beef patties to the recommended internal temperature of 71.1 deg C is sufficient to lessen consumer exposure to any STEC present.

Last Modified: 06/25/2017
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