title: Effect of tenderizers combined with organic acids on Escherichia coli O157:H7 thermal resistance in non-intact beef.
abstract: Non-intact beef products include beef cuts that have been ground, mechanically tenderized, restructured, or have been injected with solutions to enhance tenderness and/or flavor. This study examined the effects of tenderizing salts and organic acids on thermal inactivation of Escherichia coli O157:H7 in a ground beef model system simulating non-intact beef products. Ground beef (95% lean; 700 g batches) was mixed (2 min) with nothing (C) or solutions (22 ml) of water (WA), calcium ascorbate (CaA, 0.86%; wt/wt), calcium chloride (CaC, 0.23%; wt/wt), acetic acid (AA, 0.3%; v/wt), citric acid (CA, 0.2%; wt/wt), NaCl (NA, 0.5%; wt/wt), and mixtures of CaA/NA, CaC/NA, AA/NA, CA/NA, CaA/CaC/NA, CaA/AA/NA, CaA/CA/NA, CaC/AA/NA and CaC/CA/NA. Samples (30 g) were extruded into test tubes, inoculated (7 log CFU/g) with E. coli O157:H7 (5-strain mixture), and stored (4 degrees C) overnight. Samples were then cooked to 60 degrees C or 65 degrees C, in a water bath, to simulate rare or medium-rare doneness of beef, respectively. Weight, fat and moisture losses, total bacterial (tryptic soy agar) and E. coli O157:H7 (modified eosin methylene blue agar, and modified sorbitol MacConkey agar) populations were determined after inoculation, storage, and cooking. Fat and moisture losses were not affected by treatment and temperature, while weight losses increased at 65 degrees C and in acid treated samples (60 degrees C). E. coli O157:H7 survivors were generally lower (P<0.05) in acid treated than non-acid treated samples. Pathogen counts in samples treated with tenderizers (CaA, CaC) and NA were not different (P> or =0.05) than those of control samples. Thus, inclusion of organic acids in beef tenderizing recipes may help in thermal inactivation of E. coli O157:H7 that may been transferred to the interior of non-intact products during their production.
authors.affiliation: Center for Meat Safety and Quality, Food Safety Cluster, Department of Animal Sciences, Colorado State University, Fort Collins, 80523-1171, USA.
authors.forename: Yohan
authors.initials: Y
authors.lastname: Yoon
authors.forename: Avik
authors.initials: A
authors.lastname: Mukherjee
authors.forename: Keith E
authors.initials: KE
authors.lastname: Belk
authors.forename: John A
authors.initials: JA
authors.lastname: Scanga
authors.forename: Gary C
authors.initials: GC
authors.lastname: Smith
authors.forename: John N
authors.initials: JN
authors.lastname: Sofos
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology*; D000222:Adaptation, Physiological; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D002417:Cattle; D019343:Citric Acid / Q000494:pharmacology*; D019453:Escherichia coli O157 / Q000254:growth & development*; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D008460:Meat / Q000382:microbiology*; D012965:Sodium Chloride / Q000494:pharmacology; D014867:Water
chemical_list: D014867:Water; D019343:Citric Acid; D012965:Sodium Chloride; D002122:Calcium Chloride; D001205:Ascorbic Acid; D019342:Acetic Acid; D002118:Calcium