Effectiveness of Trimming and/or Washing on Microbiological Quality of Beef Carcasses

Beef carcass sides (n = 48) were selected randomly on three different days in a commercial processing facility and microbiologically analyzed before being moved to the cooler. Four types of samples were obtained per side from the inside round area: no trim and no wash (NTNW); trim, but no wash (TNW); trim and wash (TW), and no trim but wash (NTW). A flame-sterilized knife, forceps, and scalpel were used for each trimming treatment and sampling. Significant differences (P < 0.05) were observed in mean aerobic plate counts (APCs) between treatments. The greatest reduction in APC (log₁₀ colony forming units [CFU] per cm²) was observed in TNW samples followed by TW and NTW, with the corresponding mean APC reductions relative to NTNW being 3.0, 0.9, and 0.3, respectively, indicating that trimming can be an effective control point in reducing bacterial contamination in the slaughter process. Although TNW samples, had the lowest counts, samples from the same location after wash (TW) had counts 2 log cycles higher than TNW samples. These results indicate that washing spreads contamination to adjacent carcass sites. However, washing of carcasses was effective in lowering microbial populations relative to the NTNW treatment. Escherichia coli and coliform counts in all samples were low (0.03 to 0.4 log₁₀ CFU/cm²); however, the mean E. coli or coliform count in NTNW samples was higher (P < 0.05) than those in the rest of the treatments.