title: Efficacy of chemical interventions against Escherichia coli O157:H7 and multidrug-resistant and antibiotic-susceptible Salmonella on inoculated beef trimmings.
abstract: Studies were conducted to compare the decontamination efficacy of six chemical treatments against Escherichia coli O157:H7 and multidrug-resistant and antibiotic-susceptible Salmonella inoculated on beef trimmings. The inocula, comprising four-strain mixtures of rifampin-resistant  E. coli O157:H7 and antibiotic-susceptible or multidrug-resistant (MDR and/or MDR-AmpC) Salmonella Newport and Salmonella Typhimurium, were inoculated (3 log CFU/cm(2)) separately onto samples (10 by 5 by 1 cm) derived from beef chuck rolls. Samples were left  untreated (control), were immersed for 30 s in acidified sodium chlorite (0.1%, pH 2.5), peroxyacetic acid (0.02%, pH 3.8), sodium metasilicate (4%, pH 12.6), Bromitize Plus (0.0225% active bromine, pH 6.6), or AFTEC 3000 (pH 1.2), or were immersed for 5 s in SYNTRx 3300 (pH 1.0). Levels of  surviving Salmonella on treated trimmings were not influenced by serotype or antibiotic resistance phenotype and were generally similar (P ≥ 0.05) or lower (P < 0.05) than levels of surviving E. coli O157:H7 regardless of antimicrobial treatment. Overall,  depending on chemical treatment (reductions within each chemical treatment were similar among all tested inocula), initial counts of E. coli O157:H7 (2.7 to 3.1 log CFU/cm(2)) were reduced (P < 0.05) by 0.2 to 1.4 log CFU/cm(2). Similarly, initial counts  of the tested Salmonella inocula (2.8 to 3.3 log CFU/cm(2)) were reduced (P < 0.05) by 0.4 to 1.4 (Salmonella Newport, antibiotic susceptible), 0.3 to 1.4 (Salmonella Newport, MDR-AmpC), 0.2 to 1.5 (Salmonella Typhimurium, antibiotic susceptible),  0.4 to 1.3 (Salmonella Typhimurium, MDR), and 0.4 to 1.5 (Salmonella Typhimurium, MDR-AmpC) log CFU/cm(2), depending on antimicrobial treatment. Reductions obtained with sodium metasilicate were 1.3 to 1.5 log CFU/cm(2), regardless of inoculum, and reductions  obtained with the five remaining antimicrobial treatments were 0.2 to 0.7 log CFU/cm(2) (depending on treatment). Findings of this study should be useful to regulatory authorities and the meat industry as they consider Salmonella contamination on beef trimmings.
authors.affiliation: Department of Animal Sciences, Colorado State University, Fort Collins, CO 80523-1171, USA.
authors.forename: Ifigenia
authors.initials: I
authors.lastname: Geornaras
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Galatios
authors.initials: G
authors.lastname: Moschonas
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Nunnelly
authors.forename: Keith E
authors.initials: KE
authors.lastname: Belk
authors.forename: Kendra K
authors.initials: KK
authors.lastname: Nightingale
authors.forename: Dale R
authors.initials: DR
authors.lastname: Woerner
authors.forename: Gary C
authors.initials: GC
authors.lastname: Smith
authors.forename: John N
authors.initials: JN
authors.lastname: Sofos
mesh_terms: D000818:Animals; D017605:Bromine Compounds / Q000494:pharmacology; D002417:Cattle; D002712:Chlorides / Q000494:pharmacology; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004202:Disinfectants / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000254:growth & development; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests / Q000379:methods*; D010463:Peracetic Acid / Q000494:pharmacology; D012475:Salmonella / Q000187:drug effects* / Q000254:growth & development; D017640:Silicates / Q000494:pharmacology
chemical_list: D017605:Bromine Compounds; D002712:Chlorides; D004202:Disinfectants; D017640:Silicates; C025349:sodium metasilicate; D010463:Peracetic Acid; C001599:chlorite