Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 2, 1997
Publication Date: N/A
Interpretive Summary: The effect of lactic acid, acetic acid, trisodium phosphate, 162 deg F water, and 89 deg F water washes on bacteria placed on beef carcass surfaces after being treated was determined during 21 days of refrigerated (38 deg F) vacuum packaged storage. Cattle feces containing low levels of Listeria innocua, Salmonella typhimurium, Escherichia coli O157:H7, and Clostridium sporogenes was used to contaminate the carcass surface. In general, growth of these four bacteria, and total bacteria, was suppressed or not observed when lactic acid or acetic acid treatments were used. Bacteria introduced to treated beef surfaces after the tissue had received a trisodium phosphate treatment demonstrated some growth suppression. Water washes of 89 or 162 deg F offered little growth suppression of pathogens during the cold storage period. The use of a final lactic or acetic acid wash during the processing of beef carcasses offers long lasting protection against growth of potentially harmful bacteria accidentally introduced after carcass processing.
Technical Abstract: The effect of 2% (vol/vol) lactic acid (LA), 2% (vol/vol) acetic acid (AA), 12% (wt/vol) trisodium phosphate (TSP), 72 deg C water (HW), and 32 deg C water (W) washes on bacteria populations introduced to beef carcass surfaces post-treatment was determined up to 21 d at 4 deg C vacuum packaged storage. Beef carcass short plates were collected from cattle immediately after harvest and subjected to the above treatments or untreated (C). Short plates were then inoculated with low levels (ca.<2 log10) of Listeria innocua, Salmonella typhimurium, Escherichia coli O157:H7, and Clostridium sporogenes contained in a bovine fecal cocktail. In general, growth of these four bacteria, aerobic bacteria, lactic acid bacteria, and pseudomonads was suppressed or not observed when LA or AA treatments were used. Bacteria introduced to treated beef tissue after the tissue had received a TSP treatment demonstrated some growth suppression, but to a lesser extent than on acid treated tissue, and in some cases grew as well as they did on untreated beef surfaces. Hot water or water washes offered little growth suppression of pathogens during subsequent storage when these bacteria were introduced to beef tissue post-treatment. The use of a final lactic or acetic acid wash during the processing of beef carcasses offers some residual efficacy in suppressing pathogen proliferation during refrigerated storage, should these bacteria be introduced immediately after carcass processing.