Reductions of Shiga Toxin–Producing Escherichia coli and Salmonella Typhimurium on Beef Trim by Lactic Acid, Levulinic Acid, and Sodium Dodecyl Sulfate Treatments

Abstract

Studies were done at 21 °C to determine the bactericidal activity of lactic acid, levulinic acid, and sodium dodecyl sulfate (SDS) applied individually and in combination on Shiga toxin-producing Escherichia coli (STEC) in pure culture and to compare the efficacy of lactic acid and levulinic acid plus SDS treatments applied by spray or immersion to inactivate STEC and Salmonella (10(7) CFU/cm2) on beef trim pieces (10 by 10 by 7.5 cm). Application of 3% lactic acid for 2 min to pure cultures was shown to reduce E. coli O26:H11, O45:H2, O111:H8, O103:H2, O121:H2, O145:NM, and O157:H7 populations by 2.1, 0.4, 0.3, 1.4, 0.3, 2.1, and 1.7 log CFU/ml, respectively. Treatment with 0.5% levulinic acid plus 0.05% SDS for <1 min reduced the populations of all STEC strains to undetectable levels (>6 log/ml reduction). Beef surface temperature was found to affect the bactericidal activity of treatment with 3 % levulinic acid plus 2% SDS (LV-SDS). Treating cold (4 °C) beef trim with LV-SDS at 21, 62, or 81 °C for 30 s reduced E. coli O157:H7 by 1.0, 1.1, or 1.4 log CFU/cm2, respectively, whereas treating beef trim at 8 °C with LV-SDS at 12 °C for 0.1, 1, 3, or 5 min reduced E. coli O157:H7 by 1.4, 2.4, 2.5, or 3.3 log CFU/cm(2), respectively. Spray treatment of beef trim at 4 °C with 5 % lactic acid only reduced the E. coli O157:H7 population by 1.3 log CFU/cm2. Treating beef trim at 8 °C with LV-SDS for 1, 2, or 3 min reduced Salmonella Typhimurium by 2.1, 2.6, and >5.0 log CFU/cm2, respectively. Hand massaging the treated beef trim substantially reduced contamination of both pathogens, with no detectable E. coli O157:H7 or Salmonella Typhimurium (<5 CFU/cm2) on beef trim pieces treated with LV-SDS. Reduction of E. coli O157:H7 and Salmonella Typhimurium populations was enhanced, but bactericidal activity was affected by the meat temperature.

Control of pathogens in biofilms on the surface of stainless steel by levulinic acid plus sodium dodecyl sulfate

“…There is a synergistic antimicrobial effect between LVA and SDS since the application of LVA or SDS individually at equivalent concentrations is considerably less effective, with only a 0.2 to 1.2-log CFU/coupon reduction. Dramatically enhanced antimicrobial efficacy when combining LVA with SDS was also observed previously (Zhao et al, 2014;Zhao et al, 2009Zhao et al, , 2010. Surfactants, like SDS, can act as antiadhesive agents and LVA may assist in removal of the attachment polymer by chelating divalent cations required to link the polymer at the surface (Frank, 2001).…”

Development of a Novel Microbicide for Control of Foodborne Pathogens

“…An alternative to chlorine-based sanitizer is developed and validated for its efficacy in various applications at food processing facilities for reduction of food borne pathogens and for their biofilm removal. 9,10 At present a patent for its application was issued by U.S. patent office and licensed by Health Pro Inc. Its efficacy has been validated in various applications.…”

Inhibitory effect of acid concentration, aging, and different packaging onEscherichia coliO157:H7 and on color stability of beef

“…The inoculum concentration was confirmed by spread plating on Plate Count Agar (PCA) (Difco) and Fluorocult® O157:H7 Agar (Merck, Darmstadt, Germany) achieving 6 log CFU/g on meat. Then, the beef samples (100 g) were placed into multilayer barrier packaging (Cryovac, Saddle Brook, NJ), and each side of the steaks were pipetted with 0.5 mL containing 8 log CFU/mL of E. coli O157:H7 (totaling 1 mL per sample) and massaged for 1 min to facilitate inoculum distribution (Zhao et al, ). Inoculated samples remained at room temperature (22 °C) for 20 min to allow bacteria attachment onto the meat surface (Huang & Chen, ).…”