The purpose of this study was to evaluate the efficacy of our newly-developed antimicrobial wash comprised of levulinic acid and sodium dodecyl sulfate (SDS) as a surface intervention to substantially reduce E. coli O157:H7 and Salmonella population on beef trim.
The bactericidal effects of 3% levulinic acid plus 2% SDS as a wash solution were closely related to beef surface temperature. When beef trim was at 5°C, 3% levulinic acid plus 2% SDS treated for 30 sec at 21°C, 62°C, and 81°C reduced 1.0, 1.1, and 1.4 log E. coli O157:H7/cm2; respectively. With beef trim at 8°C and 3% levulinic acid plus 2% SDS at 12°C, treatment for 0.1, 1, 3, and 5 min reduced 1.4, 2.4, 2.5, and 3.3 log E. coli O157:H7/cm2; respectively. Similar results were obtained with S. Typhimurium. With beef trim at 8°C and 3% levulinic acid plus 2% SDS at 8°C, treatment for 1, 2, and 3 min reduced 2.1, 2.6, and >5.0 log S. Typhimurium/cm2; respectively. Application of hand massaging to the treated beef trim substantially increased pathogen reduction. Results revealed that E. coli O157:H7 and S. Typhimurium populations on all five 3% levulinic acid plus 2% SDS-treated beef trim at 12°C for 30 sec were reduced to an undetectable level (<5 CFU/cm2) by a direct plating method compared to the water-treated control 3 log CFU/cm2. These studies revealed that a surface treatment of beef with levulinic acid plus SDS can be effective for inactivating E. coli O157:H7 and S. Typhimurium, but the bactericidal effects are closely related to the meat temperature.
Surface treatment (as a rinse/immersion) of beef trim with a chemical solution containing levulinic acid plus sodium dodecyl sulfate (SDS) substantially reduced E. coli O157:H7 and Salmonella Typhimurium populations at meat temperatures ≥8°C. Pathogen reduction can be improved by hand massaging or brushing the meat in the presence of 3% levulinic acid plus 2% SDS. A surface temperature of beef trim at ≤ 5°C substantially reduces the bactericidal effect of levulinic acid + SDS likely because hard surface of the meat trim prevents contact between beef trim and the treatment solution. A large-scale study at a beef processing plant is needed to validate efficacy of this antimicrobial wash treatment but meat should preferably be at >12°C for reduction of E. coli O157:H7 and S. Typhimurium.