Frenzel, Mark Adam (2017-07). Evaluation of Antimicrobial Interventions Applied During Further Processing of Raw Beef Products to Reduce Pathogen Contamination. Doctoral Dissertation.
Thesis
This project was designed to validate antimicrobial applications on intact beef subprimals, frozen beef, and moisture-enhanced beef for the reduction of Shiga toxinproducing Escherichia coli (STEC). In-plant validation trials were conducted to determine efficacy of interventions on Biotype I STEC surrogate microorganisms (ATCC: BAA-1427, BAA-1428, BAA-1429, BAA-1430, and BAA-1431). Two culture preparation and inoculation methods were evaluated. There was no difference (P > 0.05) between reductions of surrogate microorganisms on beef surfaces for inoculum preparation methods or for inoculation temperatures. In-plant evaluation of antimicrobial interventions for various beef cuts inoculated with surrogate E. coli and subsequently treated with solutions of lactic acid (3.5%), Citrilow(TM) (pH = 1.05), Beefxide(R) (2.0%), or peroxyacetic acid blends (PAA, 150 ppm-Inspexx(TM)150 and 190 ppm-Inspexx(TM) 200) resulted in reductions ranging from 0.1 to 0.8 log10 CFU. Following in-plant experiments, a trial evaluating the efficacy of antimicrobial solutions prepared using water from different sources was conducted, and source did not affect (P > 0.05) reductions of E. coli. Additionally, warm (55?C) lactic acid applied to frozen, inoculated beef trimmings at concentrations of 2.5% and 5.0% achieved reductions of 0.5 and 0.7 log10 CFU/g, respectively. Differences in reductions of E. coli achieved by lactic acid (2.5 and 5.0% treatment groups) applied to fresh and frozen beef surfaces were evaluated, and reductions achieved on frozen cuts treated with 5.0% lactic acid were greater (P < 0.0001) than reductions from either of the fresh treatment groups. Applying lactic acid to frozen beef resulted in up to a 0.6 log10 CFU/cm2 greater reduction than when applied to fresh beef. Bottom sirloin tri-tips were marinated using cetylpyridinium chloride (CPC; 0.02%, 0.05%, or 0.10%; added as Cecure(R)) or sodium metasilicate (SMS, 0.2%, added as AvGard(R) XP) as antimicrobial treatments. There were no differences (P > 0.05) among treatments for reduction of surface or internalized surrogate E. coli. These data suggest that additional research should be conducted to determine the most suitable application of these ingredients for moisture-enhanced beef products. Overall, these results can be used by processors to fulfill the regulatory requirements for validating their food safety/HACCP programs.
