MICROBIOLOGICAL AND VISUAL EFFECTS OF TRIMMING AND OR SPRAY WASHING FOR REMOVAL OF FECAL MATERIAL FROM BEEF/

Microbiological and visual evaluations were performed to compare the e fficacy of hand trimming, spray washing, or a combination of treatment s, in the removal of bacteria and fecal material from beef adipose tis sue. Subcutaneous adipose samples with intact fascia from the surfaces of briskets (obtained within 15 min postmortem) were inoculated on di fferent sizes of surface areas (0, 0.3125, 0.625, 1.25, 1.875, or 2.50 cm(2)) with a bovine fecal paste containing a culture of streptomycin -resistant Escherichia coli ATCC 11370. The samples were then spray wa shed with water at 35 degrees C in a specially designed automated spra y washing cabinet at pressures of 2.76, 13.79, 20.68, or 27.58 bar and at chain speeds equivalent to 100, 200 or 300 carcasses per hour (exp osure times of 36, 18, or 12 s). Total aerobic mesophilic plate counts , streptomycin-resistant bacterial plate counts and visual scores for fecal contamination were obtained. There was a reduction (P<0.05) in m icrobiological counts on the treated samples compared with those on th e unwashed and/or untrimmed inoculated (control) samples. The variatio n in removal of fecal material from, and in reduction of microbiologic al contamination on, different sizes of surface areas of fecal materia l contamination and with different chain-speeds was minor under the co nditions of the study. Hand trimming followed by spray washing compare d to spray washing atone were similiar in their effectiveness for redu ction of microbiological contamination and slightly different in the e xtent of fecal material removal. Overall, however, higher spray washin g pressures (20.68 or 27.58 bar) were more effective (P<0.05) than the lower spray washing pressures (2.76 or 13.79 bar) in removing fecal m aterial from and reducing bacterial numbers on adipose tissue samples.