|Kalchayanand, Norasak - Nor|
|Bosilevac, Joseph - Mick|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2012
Publication Date: 7/1/2012
Citation: Kalchayanand, N., Arthur, T.M., Bosilevac, J.M., Schmidt, J.W., Wang, R., Shackelford, S.D., Wheeler, T.L. 2012. Evaluation of commonly used antimicrobial interventions for fresh beef inoculated with Shiga toxin-producing Escherichia coli serotypes O26, O45, O103, O111, O121, O145, and O157:H7. Journal of Food Protection. 75(7):1207-1212.
Interpretive Summary: The beef industry has been working for many years to minimize the risk of product contamination with E. coli O157:H7. Because other non-O157 Shiga-toxigenic E. coli (STEC) also can threaten consumers’ health as well as cause economic loss due to illnesses, the USDA Food Safety Inspection Service intends to begin regulating non-O157 STEC serotypes O26, O45, O103, O111, O121, and O145 as adulterants in certain raw beef products the same as E. coli O157:H7. Although numerous antimicrobial interventions targeting E. coli O157:H7 have been developed and implemented to decontaminate meat and meat products during the harvesting process, the information on efficacy of these interventions against non-O157 STECs is limited. This study was designed to determine the effectiveness of four commonly used antimicrobial interventions (hot water, lactic acid, peroxyacetic acid, and acidified sodium chlorite) against the six non-O157 STEC that most often cause human disease. The results indicate that antimicrobial interventions currently used in the meat industry were as effective against the top six non-O157 STEC serotypes as they were against E. coli O157:H7.
Technical Abstract: Although numerous antimicrobial interventions targeting E. coli O157:H7 have been developed and implemented to decontaminate meat and meat products during the harvesting process, the information on efficacy of these interventions, against the “big six” non-O157 STEC strains is limited. One-hundred and ninety-two pre-rigor beef flanks were used in inoculation studies to determine if antimicrobial interventions currently used by the meat industry have a similar effect in reducing non-O157 STEC serogroups O26, O45, O103, O111, O121, and O145 compared to E. coli O157:H7. A high (10**4 CFU/cm**2) or a low (10**1 CFU/cm**2) inoculation of two cocktail mixtures was applied to surfaces of fresh beef and subjected to spray treatments by the following four antimicrobial compounds: acidified sodium chlorite (1,000 ppm), peroxyacetic acid (200 ppm), lactic acid (4%), and hot water (85°C). High level inoculation samples were enumerated for the remaining bacteria populations following each treatment and compared to the untreated controls, while low level inoculation samples were chilled for 48 h at 4°C before enrichment, immunomagnetic separation, and isolation. Of the antimicrobial interventions studied, spray treatments with hot water were the most effective, resulting in mean pathogen reductions of 3.2 to 4.2 log CFU/cm**2, followed by lactic acid (reductions of 1.6 to 2.7 log CFU/cm**2). Hot water and lactic acid also were the most effective interventions with the low level inoculation on surfaces of fresh beef flanks after chilling. Peroxyacetic acid had an intermediate effect (0.9 to 1.5 log CFU/cm**2), while acidified sodium chlorite was the least effective in reducing STEC levels immediately after treatment. Results indicate that the reduction of non-O157 STEC serotypes O26, O45, O103, O111, O121, and O145 by antimicrobial interventions on fresh beef surfaces were at least as great as for E. coli O157:H7.