Comparison of Water Wash, Trimming, and Combined Hot Water and Lactic Acid Treatments for Reducing Bacteria of Fecal Origin on Beef Carcasses

Abstract

Cleaning treatments, such as high-pressure water wash at 35 degrees C or trim, alone and combined with sanitizing treatments, such as hot water (95 degrees C at the source), warm (55 degrees C) 2% lactic acid spray, and combinations of these two sanitizing methods, were compared for their effectiveness in reducing inoculated numbers (5.0 to 6.0 log CFU/cm2) of Salmonella typhimurium, Escherichia coli O157:H7, aerobic plate counts, Enterobacteriaceae, total coliforms, thermotolerant coliforms, and generic E. coli on hot beef carcass surface areas in a model carcass spray cabinet. Log reductions in numbers of all tested organisms by water wash or trim alone were significantly smaller than the log reductions obtained by the different combined treatments. Regardless of the cleaning treatment (water wash or trim) or surface area, the range for mean log reductions by hot water was from 4.0 to > 4.8 log CFU/cm2, by lactic acid spray was from 4.6 to > 4.9 log CFU/cm2, by hot water followed by lactic acid spray was from 4.5 to > 4.9 log CFU/cm2, and by lactic acid spray followed by hot water was from 4.4 to > 4.6 log CFU/cm2, for S. typhimurium and E. coli O157:H7. Identical reductions were obtained for thermotolerant coliforms and generic E. coli. No differences in bacterial reductions were observed for different carcass surface regions. Water wash and trim treatments caused spreading of the contamination to other areas of the carcass surface while providing an overall reduction in fecal or pathogenic contamination on carcass surface areas. This relocated contamination after either water wash or trim was most effectively reduced by following with hot water and then lactic acid spray. This combined treatment yielded 0% positive samples for S. typhimurium, E. coli O157:H7, thermotolerant coliforms, and generic E. coli on areas outside the inoculated areas, whereas percent positive samples after applying other combined treatments ranged from 22 to 44% for S. typhimurium, 0 to 44% for E. coli O157:H7, and 11 to 33% for both thermotolerant coliforms and generic E. coli. From data collected in this study, it is possible to choose an effective, inexpensive treatment to reduce bacterial contamination on beef carcasses. In addition, the similar reduction rates of total coliforms, thermotolerant coliforms, or generic E. coli may be useful in identifying an indicator to verify the effectiveness of the selected treatment as a critical control point in a Hazard Analysis and Critical Control Point program.

Effect of different durations of exposure to food-grade organic lactic acid on the growth of S. aureus and E. coli in meat from Persian sheep (Afshari breed) stored at refrigeration temperature

“…Bosilevac et al (2006) reported that the bacterial count for E. coli was 3 log 10 CFU/100 cm 2 in response to the spraying of 2% lactic acid on carcass tissue, a reduction of 1.0 log CFU/100 cm 2 compared to the control group. However, the results reported here show that the efficacy of 1-3% lactic acid in reducing E. coli was lower than in this previous study; 2% lactic acid reduced E. coli numbers by 0.1 log 10 CFU/g in sheep meat at 96 h. In some studies in which inocula were experimentally added to meat samples (Castillo et al 1998(Castillo et al , 1999(Castillo et al , 2001, colony counts showed large reductions of greater than 4 log 10 CFU/g. Similar to this study, levels were reduced to less than 1 log 10 CFU/g when natural contaminants were evaluated (Dormedy et al 2000;Gill & Badoni 2004).…”

Treatments Using Hot Water Instead of Lactic Acid Reduce Levels of Aerobic Bacteria and Enterobacteriaceae and Reduce the Prevalence of Escherichia coli O157:H7 on Preevisceration Beef Carcasses

“…For valid comparisons to be made, two different sets of data based on the inoculum used must be distinguished. In one set of studies, large reductions of greater than 4 log CFU (APC, Salmonella Typhimurium, E. coli O157:H7, and coliforms) were found when laboratory strains were used to inoculate beef surfaces (10,12,13). In the other set of studies, smaller reductions of 0.8 to 1.2 log CFU were found when natural contamination was evaluated (15,22).…”

“…Lactic acid has been described as an effective intervention on cold or chilled beef carcasses (13,18,22) and on hot beef carcasses (10,12,15), even though these surfaces can be very different. In those studies, the concentration of lactic acid was either 2 or 4% and the application temperatures were approximately 32ЊC (90ЊF) or 55ЊC (131ЊF).…”

Reduction of Escherichia coli O157:H7 Shedding in Cattle by Addition of Chitosan Microparticles to Feed

“…Practices to prevent or reduce E. coli O157:H7 contamination of beef carcasses are primarily applied at the processing level, with the most common treatments being hide washes, trimming of contaminated carcass parts, steam vacuuming, hot water and acid washes, and steam treatment (1,2,4,5). Despite the implementation of these practices, there continue to be significant numbers of recalls and beef-linked illness caused by this pathogen.…”