title: Effect of Exposure Time and Organic Matter on Efficacy of Antimicrobial Compounds against Shiga Toxin-Producing Escherichia coli and Salmonella.
abstract: Several antimicrobial compounds are in commercial meat processing plants for pathogen control on beef carcasses. However, the efficacy of the method used is influenced by a number of factors, such as spray pressure, temperature, type of chemical and concentration, exposure time, method of application, equipment design, and the stage in the process that the method is applied. The objective of this study was to evaluate effectiveness of time of exposure of various antimicrobial compounds against nine strains of Shiga toxin-producing Escherichia coli (STEC) and four strains of Salmonella in aqueous antimicrobial solutions with and without organic matter. Non-O157 STEC, STEC O157:H7, and Salmonella were exposed to the following aqueous antimicrobial solutions with or without beef purge for 15, 30, 60, 120, 300, 600, and 1,800 s: (i) 2.5% lactic acid, (ii) 4.0% lactic acid, (iii) 2.5% Beefxide, (iv) 1% Aftec 3000, (v) 200 ppm of peracetic acid, (vi) 300 ppm of hypobromous acid, and (vii) water as a control. In general, increasing exposure time to antimicrobial compounds significantly (P ≤ 0.05) increased the effectiveness against pathogens tested. In aqueous antimicrobial solutions without organic matter, both peracetic acid and hypobromous acid were the most effective in inactivating populations of STEC and Salmonella, providing at least 5.0-log reductions with exposure for 15 s. However, in antimicrobials containing organic matter, 4.0% lactic acid was the most effective compound in reducing levels of STEC and Salmonella, providing 2- to 3-log reductions with exposure for 15 s. The results of this study indicated that organic matter and exposure time influenced the efficacy of antimicrobial compounds against pathogens, especially with oxidizer compounds. These factors should be considered when choosing an antimicrobial compound for an intervention.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, State Spur 18D, Clay Center, Nebraska 68933-0166, USA. norasak.kalchayanand@ars.usda.gov.
authors.forename: Norasak
authors.initials: N
authors.lastname: Kalchayanand
authors.affiliation: IEH Laboratories and Consulting Group, 15300 Bothell Way N.E., Lake Forest Park, Washington 98155, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Koohmaraie
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Roman L. Hruska U.S. Meat Animal Research Center, P.O. Box 166, State Spur 18D, Clay Center, Nebraska 68933-0166, USA.
authors.forename: Tommy L
authors.initials: TL
authors.lastname: Wheeler
mesh_terms: D000818:Animals; D001959:Bromates / Q000494:pharmacology; D002417:Cattle; D004202:Disinfectants / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005511:Food Handling / Q000379:methods; D005519:Food Preservation / Q000295:instrumentation / Q000379:methods*; D019344:Lactic Acid / Q000494:pharmacology; D008460:Meat / Q000382:microbiology; D010463:Peracetic Acid / Q000494:pharmacology; D012475:Salmonella / Q000187:drug effects; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects* / Q000254:growth & development
chemical_list: D001959:Bromates; D004202:Disinfectants; D019344:Lactic Acid; C027664:hypobromous acid; D010463:Peracetic Acid