Chlorine dioxide spray washes for reducing fecal contamination on beef

The ability of chlorine dioxide (ClO2) to reduce bacterial populations (i.e., aerobic plate count, APC) on fecally contaminated beef carcass tissue (BCT) was examined in two separate experiments. In the first study, individual pieces of BCT were inoculated with fresh bovine feces to obtain approximately 6.60 log APC/cm(2) and spray treated (10 s; 520 kPa; 16 degrees C) with ClO2 at tank concentrations ranging from 0 to 20 ppm. Bacterial populations were reduced by no more than 0.93 log CFU/cm(2), regardless of ClO2 concentration, and were not statistically different (P greater than or equal to 0.05) from water-treated BCT. In the second study, tap water (16 degrees C) and ClO2 at a tank concentration of 20 ppm (16 degrees C) were sprayed (690 kPa) for 15, 30, and 60 s onto BCT inoculated with fresh bovine feces to obtain approximately 5.80 log APC/cm(2) and the remaining bacterial populations compared. While spray treatments with ClO2 or water reduced APC by 1.53 to 2.07 log CFU/cm(2), spray treatments with either water or ClO2, at 15, 30 or 60 s were not statistically different (P greater than or equal to 0.05). Similar reductions (1.61 log CFU/cm(2)) were observed when BCT was spray treated for 60 s with tap water followed by a 60 s spray wash with ClO2. These results demonstrate that spray treatments with ClO2 are no more effective than water for reducing fecal contamination on beef.