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United States Department of Agriculture

Agricultural Research Service

Research Project: PATHOGEN PERSISTENCE AND PROCESSING OPTIMIZATION FOR ELIMINATION IN FOODS

Location: Food Safety and Intervention Technologies

Title: Distribution and detection of Shiga toxin-producing Escherichia coli (STEC) during an industrial grinding process of beef trim

Authors
item Phebus, Randall -
item Luchansky, John
item Porto Fett, Anna
item Thippareddi, Harshavardhan -
item Singh, Manpreet -
item Sullivan, Rachel -
item Hettenbach, Susan -
item Wolf, John -
item Paddock, Casey -
item Baumann, Nicholas -
item Sevart, Nicholas -
item Minto, Michael -
item Harper, Nigel -
item Senecal, Andre -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 2013
Publication Date: July 28, 2013
Citation: Phebus, R.K., Luchansky, J.B., Porto Fett, A.C., Thippareddi, H., Singh, M., Sullivan, R.R., Hettenbach, S., Wolf, J., Paddock, C., Baumann, N., Sevart, N., Minto, M., Harper, N., Senecal, A. 2013. Distribution and detection of Shiga toxin-producing Escherichia coli (STEC) during an industrial grinding process of beef trim. Meeting Abstract.IAFP Annual Meeting, Charlotte, North Carolina, July 28-31, 2013., 76:82 (P1-44).

Technical Abstract: During the grinding and packaging processes, it is important to understand how Shiga toxin-producing Escherichia coli (STEC) would be distributed and how well it could be detected in beef trim. This study is important because it shows what would happen if contaminated meat is allowed into a commercial beef grinding process and the limits of detection. STEC was surface inoculated onto a 908-g piece of beef trim (4.1, 1.0, and 0.5 log cfu/g for replications 1, 2, and 3, respectively) and was then processed with approximately 1,650 kg of beef trim. The manufacturing line was configured in a loop so that the meat was ground (first grind), sent to the blender to mix, ground again (second grind), and finally packaged using a VEMAG chub packager. Samples were enriched from the first grind and the second grind and STEC presence was determined using PCR. All samples for rep 1 were positive for STEC for both the first and second grinds. For rep 2, nearly all samples were positive during the first grind until after 772 kg were processed. However, the second grind of rep 2 was positive for the first 136 kg and negative for almost all samples after. Only five of the 27 samples were negative for the first grind of rep 3. All samples were positive for STEC after the second grind. It is obvious that when the STEC concentration was greater for rep 1, the contamination was high enough to be distributed throughout the process. This study shows that even at low levels of STEC contamination, the bacterium is still found throughout the process. This also shows that STEC can be effectively detected using PCR following enrichment.

Last Modified: 8/21/2014