Shiga toxin-producing Escherichia coli in meat: a preliminary simulation study on detection capabilities for three sampling methods

Authors: COUTON, JULIE - University Of Nebraska; MARX, DAVID - University Of Nebraska; Luchansky, John; PHEBUS, RANDALL - Kansas State University; Porto-Fett, Anna; SEVART, NICHOLAS - Kansas State University; SINGH, MANPREET - Purdue University; THIPPAREDDI, HARSHARVARDAN - University Of Georgia

Submitted to: Applied Statistics In Agriculture Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/4/2017
Publication Date: 1/4/2017
Citation: Couton, J., Marx, D., Luchansky, J.B., Phebus, R.K., Porto Fett, A.C., Sevart, N., Singh, M., Thippareddi, H. 2017. Shiga toxin-producing Escherichia coli in meat: a preliminary simulation study on detection capabilities for three sampling methods. Applied Statistics In Agriculture Conference Proceedings. PP.90-100. In Proceedings of the 27th Conference on Applied Statistics in Agriculture. Manhattan, KS; Kansas State University, Department of Statistics

Interpretive Summary: Contamination by Shiga Toxin-producing Escherichia coli (STEC) is a continuing concern for meat production facility management throughout the United States. Several methods have been used to detect STEC during meat processing, however the excessive experimental cost of determining the optimal method is rarely feasible. Our research showed that if the contamination is less than 0.01% all three sampling methods (i.e., Cozzini core sampler, core drill shaving, and N-60 surface excision) struggled to detect contamination, whereas at levels greater than 10% all three methods were effectively detecting the contamination. Over moderate levels of contamination (between 1% and 5%) core drill shaving and N-60 surface excision perform significantly better than Cozzini core sampler at all levels. There does not appear to be a significant difference between core drill shaving and N-60. As such, all three methods would be useful to recover target bacteria from meats.

Technical Abstract: The objective of this simulation study is to determine which sampling method (Cozzini core sampler, core drill shaving, and N-60 surface excision) will better detect Shiga Toxin-producing Escherichia coli (STEC) at varying levels of contamination when present in the meat. 1000 simulated experiments were studied using a binary model for rare occurrences to find the optimal method. We found that all sampling methods performed equally for meat contamination levels less than 0.1% or greater than 10%. At moderate levels of contamination (between 0.1% and 10%) core drill shaving and N-60 performed significantly better than Cozzini core sampler. However, there does not appear to be a significant difference between core drill shaving and N-60.