title: Evaluation of lactic acid as an initial and secondary subprimal intervention for Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli, and a nonpathogenic E. coli surrogate for E. coli O157:H7.
abstract: Lactic acid can reduce microbial contamination on beef carcass surfaces when used as a food safety intervention, but effectiveness when applied to the surface of chilled beef subprimal sections is not well documented. Studies characterizing bacterial reduction on subprimals after lactic  acid treatment would be useful for validations of hazard analysis critical control point (HACCP) systems. The objective of this study was to validate initial use of lactic acid as a subprimal intervention during beef fabrication followed by a secondary application to vacuum-packaged product  that was applied at industry operating parameters. Chilled beef subprimal sections (100 cm(2)) were either left uninoculated or were inoculated with 6 log CFU/cm(2) of a 5-strain mixture of Escherichia coli O157:H7, a 12-strain mixture of non-O157 Shiga toxin-producing  E. coli (STEC), or a 5-strain mixture of nonpathogenic (biotype I) E. coli that are considered surrogates for E. coli O157:H7. Uninoculated and inoculated subprimal sections received only an initial or an initial and a second "rework" application of lactic  acid in a custombuilt spray cabinet at 1 of 16 application parameters. After the initial spray, total inoculum counts were reduced from 6.0 log CFU/cm(2) to 3.6, 4.4, and 4.4 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation  groups, respectively. After the second (rework) application, total inoculum counts were 2.6, 3.2, and 3.6 log CFU/cm(2) for the E. coli surrogates, E. coli O157:H7, and non-O157 STEC inoculation groups, respectively. Both the initial and secondary lactic acid treatments  effectively reduced counts of pathogenic and nonpathogenic strains of E. coli and natural microflora on beef subprimals. These data will be useful to the meat industry as part of the HACCP validation process.
authors.affiliation: Center for Meat Safety & Quality, Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523-1171, USA.
authors.forename: C I
authors.initials: CI
authors.lastname: Pittman
authors.forename: I
authors.initials: I
authors.lastname: Geornaras
authors.forename: D R
authors.initials: DR
authors.lastname: Woerner
authors.forename: K K
authors.initials: KK
authors.lastname: Nightingale
authors.forename: J N
authors.initials: JN
authors.lastname: Sofos
authors.forename: L
authors.initials: L
authors.lastname: Goodridge
authors.forename: K E
authors.initials: KE
authors.lastname: Belk
mesh_terms: D000818:Animals; D002417:Cattle / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D003663:Decision Trees; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods; D019344:Lactic Acid / Q000494:pharmacology*; D008460:Meat / Q000382:microbiology*; D054323:Shiga-Toxigenic Escherichia coli / Q000187:drug effects / Q000254:growth & development; D014618:Vacuum
chemical_list: D019344:Lactic Acid