Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2013
Publication Date: 12/1/2013
Publication URL: http://handle.nal.usda.gov/10113/59040
Citation: Wang, R., King, D.A., Koohmaraie, M., Bosilevac, J.M. 2013. Impact of sampling area and location on measurement of indicator organisms during beef carcass interventions. Journal of Food Protection. 76(12):2069-2073.
Interpretive Summary: Escherichia coli O157:H7 is an important foodborne pathogen being regulated as an adulterant in beef products. Commercial meat processors have employed antimicrobial interventions to prevent beef carcass contamination by E. coli O157:H7. To ensure that the intervention procedure is functioning properly and efficiently, processors often monitor the levels of indicator microorganisms. In the present study, the effect of sponge sampling site and area on the recovery of multiple indicator microorganisms from beef carcass surfaces was evaluated in order to simplify and validate our previous sampling protocol for ease of implementation by the meat industry. Results indicated that pre-intervention samples collected from the top or bottom sites of the carcasses were similar in recovery of the indicator organisms. The top-bottom combined sponge samples would provide similar data as well. Post-intervention samples obtained from the bottom site of the carcasses showed the most reductions of viable microorganisms. These results suggested that instead of sampling both top and bottom sites of the carcasses, which is frequently unfeasible in the commercial setting, samples collected with this method from either top or bottom site could be suitable for use to monitor background levels of the indicator microorganisms.
Technical Abstract: The effect of sponge sample collection site on the recovery of multiple indicator organisms from beef carcass surfaces was evaluated. Two 4,000 cm2 samples were collected from pre-evisceration carcasses (n=248), one from the inside and outside round area (top site) and one from the navel-plate-brisket-foreshank area (bottom site). One-half of the samples (n=124) were collected before a wash cabinet intervention and the other half after the intervention. The numbers of total aerobic bacteria, Enterobacteriaceae, coliforms, and Escherichia coli were determined for one-half of each individual sponge sample. The other halves of the sponges were combined to represent a top + bottom 8,000 cm2 sample. For the pre-intervention carcasses, 4,000 cm2 samples collected from the top- or bottom- sites of the carcasses were not significantly different (P > 0.05) from each other or from the 8,000 cm2 combined sample in recovery of the indicator organisms. Post-intervention 4,000 cm2 carcass samples collected from the bottom site recovered less organisms (P < 0.05) compared to the samples collected from the top site and the combined 8,000 cm2 samples. Results indicated that levels of pre-intervention indicator organisms were unlikely to differ when collected from either site of a beef carcass surface. However, overall reductions observed using 4,000 cm2 sites can vary based on the intervention in place, therefore assessment of intervention efficacy may differ based on the sites selected for sampling.