MICROBIAL DECONTAMINATION OF BEEF AND SHEEP CARCASSES BY STEAM, HOT-WATER SPRAY WASHES, AND A STEAM-VACUUM SANITIZER

Three separate studies were conducted to determine the effectiveness o f various temperature water spray washes (W-t), wash and steam combina tions (WtS), and vacuum and wash combinations (VWt) for reducing fecal bacteria on sheep and beef carcasses. W-t of 15.6, 54.4, and 82.2 deg rees C were administered to sheep carcasses contaminated with feces, u sing a hand-held spray nozzle. Initial carcass bacterial populations o f approximately 2.5, 4, and 6 log CFU/cm(2) were subjected to all wash combinations. W-82.2 and W82.2S reduced 6 log CFU/cm(2) bacterial pop ulations as much as 4.0 log cycles. When carcasses were subjected to W tS and W-82.2, the initial contamination levels (4 and 6 log CFU/cm(2) ) had little effect on final bacterial levels (2.7 to 3.3 log CFU/cm(2 )). However, uninoculated carcasses with initial bacterial populations of 2.5 log CFU/cm(2) experienced a 1.5-log-cycle reduction when subje cted to WtS and W-82.2. It is possible that hydration of a carcass bef ore and during interventions affords some protection to bacteria. The next study used a commercial carcass washer to apply a hot water (72 d egrees C), low pressure (20 psi) wash in combination with a high press ure (125 psi), warm water (30 degrees C) wash (W-72/30). Reductions on beef of 2.7, 3.3, and 3.4 log cycles for aerobic plate count (APC), c oliforms, and E. coli populations, respectively, were observed. When a commercial steam-vacuum was used in conjunction with W-72/30, reducti ons of 3.1, 4.2, and 4.3 log cycles for APC, coliforms, and E. coli po pulations, respectively, were achieved. Implementation of these interv entions could reduce the amount of trimming needed on carcass-processi ng lines and would increase the microbial safety of beef carcasses. 0