The effects of a trichloromelamine wash on Escherichia coli O157:H7 and Salmonella spp. prevalence on beef hides

In a multi-stage experiment, the efficacy of Trichloromelamine (TCM), a chlorine-containing disinfectant compound, on the reduction of Escherichia coli 0157:H7 and Salmonella spp. on beef hides at an abattoir was determined. Twenty head of cattle were sampled on each of two consecutive days of each week during a six-week period. A preliminary swab was taken from each head immediately following exsanguinations. Cattle were then sprayed with TCM and a second swab was taken immediately prior to hide removal. Swabs were then analyzed for prevalence of E. coli 0157:H7 and Salmonella spp.. In a second trial, swabs were taken both prior to and following treatment. Treatment in this trial included TCM and TCM plus a thickening agent (TCM + T), with ten head receiving each treatment. In a third experiment, individual hide samples were spread with fecal slurries which were inoculated with K coli 0157:H7 and Salmonella spp.. Hide samples were sprayed with TCM or TCM + T and allowed a dwell time of 1 to 10 minutes. E. coli and Salmonella spp. were then enumerated for each hide sample. In the first trial, significant decreases were seen for E. coli 0157JI7 (P < 0.0002) and Salmonella spp. (P < 0.0001). No significant decreases were observed for E. coli 0157:H7 in the second trial due to a small number of preliminary positives. Significant decreases in Salmonella spp. were seen from TCM and TCM + T treatments (P < 0.0001). A significant difference was also observed between TCM and TCM + T treatments with TCM + T having a greater reduction (P < 0.05). In the enumeration study, significant log reduction was not seen for E coli 0157:H7 for either treatment. Both treatments exhibited a significant log reduction (P < 0.0001). Results of this study indicate TCM is an effective in-slaughter means of microbial intervention.