DECONTAMINATION OF BEEF CARCASS TISSUE WITH NISIN USING A PILOT-SCALE MODEL CARCASS WASHER

Nisin spray treatments were tested for controlling Gram-positive bacteria attached to beef carcass surface tissue using a pilot scale model carcass washer. Sections of lean and adipose tissues were inoculated with approximately 4 log(10) cfu cm(-2) of Brochothrix thermosphacta, Carnobacterium divergens or Listeria innocua. Following 28 degrees C water or nisin sprays, bacterial populations were enumerated immediately and after incubation for 24 h at 4 degrees C. Spray treatments with water did not significantly alter the bacterial populations at day 0 or 1 (<1 log(10) reduction). However, nisin spray treatments (5000 AU ml(-1)) reduced populations by 1.79 to 3.54 log(10) cfu cm(-2) at day 0 and by 1.97 to 3.60 log(10) cfu cm(-2) at day 1. This study demonstrates that spray washing is an effective means of applying bacteriocins and that these compounds may be useful as sanitizers of red meat carcasses.