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/cm² and spray treated (10 s; 520 kPa; 16°C) with ClO₂ at tank concentrations ranging from 0 to 20 ppm. Bacterial populations were reduced by no more than 0.93 log CFU/cm², regardless of ClO₂ concentration, and were not statistically different (P ≥ 0.05) from water-treated BCT. In the second study, tap water (16°C) and ClO₂ at a tank concentration of 20 ppm (16°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/cm² and the remaining bacterial populations compared. While spray treatments with ClO₂ or water reduced APC by 1.53 to 2.07 log CFU/cm², spray treatments with either water or ClO₂ at 15, 30 or 60 s were not statistically different (P ≥ 0.05). Similar reductions (1.61 log CFU/cm²) 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.