REDUCTION OF FOODBORNE MICROORGANISMS ON BEEF CARCASS TISSUE USING ACETIC-ACID, SODIUM-BICARBONATE, AND HYDROGEN-PEROXIDE SPRAY WASHES

In an attempt to control beef carcass contamination, a search for effe ctive carcass washing treatments has become a major focus in the area of microbiological meat safety. Spray-wash treatments utilizing 1.0% a cetic acid, 3% hydrogen peroxide, 1% sodium bicarbonate, alone or in c ombination, were performed to evaluate their efficacy in reducing numb ers of Escherichia coli, Listeria innocua and Salmonella wentworth. Th e fascia surface of lean and adipose tissue was inoculated with steril ized fecal slurry containing the designated bacteria to obtain 5 log(1 0) cfu cm(-2). A pilot scale model carcass washer was used to apply th e spray treatment (80 psi, 15 s, 25 degrees C). Control samples receiv ed no spray treatments. Following treatments, lean and adipose samples were immediately analyzed or held for 24 h at 5 degrees C for analysi s of the treatments, for residual bacterial populations, surface pH, c olor analysis, and residual hydrogen peroxide. The combination wash of acetic acid/3% hydrogen peroxide (AAHP) resulted in the greatest redu ctions of 3.97 and 3.69 log(10) cfu cm(-2) for E. coli on lean or adip ose tissue, respectively. Spray washes with AAHP reduced L. innocua by 3.05 log(10) cfu cm(-2) on lean tissue and 3.52 log(10) cfu cm(-2) on adipose tissue, while S. wentworth was reduced by 3.37 log(10) cfu cm (-2) on lean and 3.69 log(10) cfu cm(-2) on adipose tissue. A spray-wa sh treatment consisting of the right combination of safe and acceptabl e solutions may be effective for improving the microbial safety of bee f. (C) 1997 Academic Press Limited.