Antimicrobial Efficacy of a Lactic Acid and Citric Acid Blend against Shiga Toxin-Producing Escherichia coli, Salmonella, and Nonpathogenic Escherichia coli Biotype I on Inoculated Prerigor Beef Carcass Surface Tissue

Abstract

Studies were conducted to (i) determine whether inoculants of nonpathogenic Escherichia coli biotype I effectively served as surrogates for E. coli O157:H7, non-O157 Shiga toxin-producing E. coli, and Salmonella when prerigor beef carcass tissue was treated with a commercially available blend of lactic acid and citric acid (LCA) at a range of industry conditions of concentration, temperature, and pressure; (ii) determine the antimicrobial efficacy of LCA; and (iii) investigate the use of surrogates to validate a hot water and LCA sequential treatment as a carcass spray intervention in a commercial beef harvest plant. In an initial laboratory study, beef brisket tissue samples were left uninoculated or were inoculated (∼6 log CFU/cm(2)) on the adipose side with E. coli O157:H7 (5-strain mixture), non-O157 Shiga toxin-producing E. coli (12-strain mixture), Salmonella (6-strain mixture), or nonpathogenic E. coli (5-strain mixture). Samples were left untreated (control) or were treated with LCA, in a spray cabinet, at one of eight combinations of solution concentration (1.9 and 2.5%), solution temperature (43 and 60°C), and application pressure (15 and 30 lb/in(2)). In a second study, the E. coli surrogates were inoculated (∼6 log CFU/cm(2)) on beef carcasses in a commercial facility to validate the use of a hot water treatment (92.2 to 92.8°C, 13 to 15 lb/in(2)) followed by an LCA treatment (1.9%, 50 to 51.7°C, 13 to 15 lb/in(2), 10 s). In the in vitro study, surrogate and pathogen bacteria did not differ in their response to the tested LCA treatments. Treatment with LCA reduced (P < 0.05) inoculated populations by 0.9 to 1.5 log CFU/cm(2), irrespective of inoculum type. The hot water and LCA sequential treatments evaluated in the commercial facility reduced (P < 0.05) the inoculated nonpathogenic E. coli surrogates on carcasses by 3.7 log CFU/cm(2). This study therefore provides the meat industry with data for this sequential multiple hurdle system for the operation parameters described.

Effect of Peracetic Acid Solutions and Lactic Acid on Microorganisms in On-Line Reprocessing Systems for Chicken Slaughter Plants

“…The literature is inconstant in describing changes in bacterial load on carcasses along the slaughter line: studies show both increasing and decreasing numbers of different microorganisms, such as Campylobacter, E. coli, and Salmonella on the carcasses during the slaughtering and cutting process without sanitation in place. Interherd crosscontaminations by Campylobacter and Salmonella, for example, are also described (1,3,17,18,21,22,25,26).…”

Influences of epigallocatechin gallate and citric acid on Escherichia coli O157:H7 toxin gene expression and virulence-associated stress response

“…Organic acids, particularly citric acid, have also been used to prevent micro‐organisms in some food products (Scott et al . ). Tea polyphenols may have synergistic effect with organic acids.…”

Enhanced Antimicrobial Activity Based on a Synergistic Combination of Sublethal Levels of Stresses Induced by UV-A Light and Organic Acids

“…The limited antimicrobial activity of these organic acids is likely due to the short exposure time, up to 30 min, and the low concentrations of GA and LA, 1 mM and 5 mM, respectively. In fact, most studies reporting GA and LA as antimicrobial agents are based on a longer incubation time (1 to 24 h) and/or usually at higher concentration levels (30 to 300 mM) (27,(43)(44)(45)(46).…”