Efficacy Of Antimicrobial Interventions Research Articles

Efficacy of Antimicrobial Interventions Used in Meat Processing Plants against Antimicrobial Tolerant Non–Antibiotic-Resistant and Antibiotic-Resistant Salmonella on Fresh Beef

Salmonella is a common cause of foodborne illness in the United States, and several strains of Salmonella have been identified as resistant to antibiotics. It is not known whether strains that are antibiotic resistant (ABR) and that have some tolerance to antimicrobial compounds are also able to resist the inactivation effects of antimicrobial interventions used in fresh meat processing. Sixty-eight Salmonella isolates (non-ABR and ABR strains) were treated with half concentrations of lactic acid (LA), peracetic acid (PAA), and cetylpyridinium chloride (CPC), which are used in beef processing plants to screen for tolerant strains. Six strains each from non-ABR and ABR Salmonella that were most tolerant of LA (2%), PAA (200 ppm), and CPC (0.4%) were selected. Selected strains were inoculated on surfaces of fresh beef and subjected to spray wash treatment with 4% LA, 400 ppm PAA, or 0.8% CPC for the challenge study. Tissue samples were collected before and after each antimicrobial treatment for enumeration of survivors. Spray treatment with LA, PAA, or CPC significantly reduced non-ABR Salmonella and ABR Salmonella on surfaces of fresh beef by 1.95, 1.22, and 1.33 log CFU/cm2, and 2.14, 1.45, and 1.43 log CFU/cm2, respectively. The order of effectiveness was LA > PAA = CPC. The findings also indicated that LA, PAA, and CPC were equally (P ≤ 0.05) effective against non-ABR and ABR Salmonella on surfaces of fresh beef. These data contribute to the body of work that indicates that foodborne pathogens that have acquired both antibiotic resistance and antimicrobial tolerance are still equally susceptible to meat processing antimicrobial intervention treatments.

Efficacy of antimicrobial interventions in reducing Salmonella enterica, Shiga toxin-producing Escherichia coli, Campylobacter, and Escherichia coli biotype I surrogates on non-chilled and chilled, skin-on and skinless pork

Effect of various antimicrobial interventions on pork carcass cuts – skin-on and skinless, non-chilled and chilled – was studied. Carcass pieces were inoculated with Salmonella enterica, Shiga toxin-producing Escherichia coli (STEC), Escherichia coli pathogen surrogates or Campylobacter spp. Inoculated pieces were assigned to one of the following antimicrobial treatments: 2.5% and 5.0% room temperature lactic acid, 2.5% and 5.0% warm (55 °C) lactic acid, 400 ppm (0.4 mg/mL) room temperature peroxyacetic acid (PAA) or warm (55 °C) water. Treated pieces were sampled before antimicrobial treatment of non-chilled pork tissue, then at 30 m and 24 h post-treatment. For chilled pork, samples were collected after 24 h chilling and 30 m post-treatment. Lactic acid and PAA treatments reduced (P < 0.05) pathogenic and surrogate bacteria; warm water did not produce similar results. Objective and sensory color evaluations on treated pork indicated minimal negative impacts on pork color. Various antimicrobial interventions were effective in reducing surrogates on pork without diminishing quality.

Antimicrobial Interventions to Reduce Shiga Toxin-Producing Escherichia coli (STEC) Surrogate Populations on Beef Striploins Intended for Blade Tenderization

ObjectivesBlade tenderization (BT) is used in the beef industry to improve tenderness of steaks prepared from subprimals but can translocate surface pathogens to the interior of meat. Application of antimicrobial solutions on the surface of subprimals prior to blade tenderization can reduce the risk of translocation of surface microorganisms. The objectives of this research were: 1) evaluate the efficacy of antimicrobial interventions applied to inoculated (surrogate Escherichia coli) beef striploins prior to blade tenderization; and 2) examine the transfer of E. coli from inoculated striploins to subsequent non-inoculated subprimals.Materials and MethodsThe anterior portion of whole muscle beef striploins (30.48 cm) were inoculated (lean side) across a 10 cm band with an approximately 8.00 log CFU/mL cocktail containing non-pathogenic, rifampicin-resistant surrogate STEC strains (BAA-1427, BAA-1428, BAA-1429, BAA-1430, and BAA-1431). The inoculated striploins were sprayed with (1) levulinic acid (5.0%) + sodium dodecyl sulfate (0.50%) (LVA+SDS), (2) peroxyacetic acid (2000 ppm; PAA; FCN 1666), (3) acidified sodium chlorite (1200 ppm; ASC), or (4) lactic acid (4.5%; LA) by passing through a spray cabinet and blade tenderized, along with an inoculated, non-sprayed control (CON). To evaluate the potential for cross-contamination of subsequent subprimals, an inoculated striploin (for each treatment) was blade tenderized followed by a non-inoculated beef striploin. For each striploin, surface and subsurface samples (2.54 cm wide) were collected from three different locations including the anterior, middle, and posterior end of each striploin. A total of 30 striploins across three replications were randomly assigned to treatment stratification. Sponge samples were also collected from the blade tenderizer (plate of the blade unit and blades) after each treatment group. Data were analyzed using Proc Mixed (SAS Inst., v.9.4; Cary, NC) as a completely randomized split-plot design. Microbial counts for all samples were log transformed and then analyzed for the main effects of antimicrobial treatment, location (anterior to posterior and surface or interior), and their interaction. Differences were considered significant at α ≤ 0.05.ResultsPAA was more effective in reducing E. coli populations (1.80 log CFU/g; P ≤ 0.05) and had lowest recovery of the microorganism from the striploin subsurface compared to other treatments, followed by LVA+SDS (1.00 log CFU/g). E. coli populations gradually decreased (P ≤ 0.05) on the surface and subsurface as sampling moved anterior to posterior. However, E. coli populations were similar (P &gt; 0.05) on the posterior end of inoculated striploins and the anterior end of the subsequent, non-inoculated striploins, indicating transfer of microorganisms from one striploin to the following striploin. E. coli populations of 3.03 log CFU/cm2 and 2.47 log CFU/cm2 were recovered from the plate of the blade unit and the blades of the blade tenderizer. E. coli populations recovered from the plastic plate (3.46 log CFU/cm2) and blades (2.87 log CFU/cm2) of the blade tenderizer were the similar (P &gt; 0.05) for all treatment groups except for PAA (1.41 log CFU/cm2 and 0.97 log CFU/cm2, respectively).ConclusionThese results showed that PAA and LVA+SDS can be used to improve the safety of blade tenderized beef.

The efficacy of antimicrobial interventions on Shiga toxin producing Escherichia coli (STEC) surrogate populations inoculated on beef striploins prior to blade tenderization

The US meat industry actively seeks antimicrobials to eliminate Shiga toxin-producing Escherichia coli (STEC) in non-intact products. To facilitate this, the anterior end (10.2 cm) of beef striploins (30.5 cm) were inoculated (lean side) with a ca. 8.00 log CFU/mL cocktail containing non-pathogenic rifampicin resistant surrogate E. coli. The inoculated striploins were passed through a spray cabinet and treated with either 50 mL/L levulinic acid +5 g/L sodium dodecyl sulfate (LVA+SDS), peroxyacetic acid (2 mL/L; PAA), acidified sodium chlorite (1.2 g/L; ASC), lactic acid (45 mL/L; LA), or no antimicrobial application (CON) and then blade tenderized. A non-inoculated beef striploin immediately followed the first striploin through the spray cabinet and blade tenderizer. Surface and subsurface samples were collected from the anterior, middle, and posterior sections of each striploin. PAA was the most effective in reducing surrogate E. coli (P ≤ 0.05) on the surface compared to all other treatment groups, followed by LVA+SDS and ASC, respectively. PAA had the lowest (P ≤ 0.05) amount of recovered subsurface E. coli. Lactic acid treated striploins were similar to untreated controls for surface and subsurface E. coli recovery. Using PAA, LVA+SDS, or ASC can improve the safety of blade tenderized striploins.