Slaughterfloor decontamination of pork carcases with hot water or acidified sodium chlorite - a comparison in two Australian abattoirs.

A decontamination trial on the effectiveness of hot water or acidified sodium chlorite (SANOVA) treatment on Salmonella spp., Escherichia coli and Total Viable Count (TVC) was undertaken on pork carcases prior to primary chilling in two large pork abattoirs in Australia using belly-strip excision sampling. A total of 123 samples from Abattoir A and 400 samples from Abattoir B were cultured and analysed. Test pigs were selected from herds with a known high level of on-farm Salmonella infection. At Abattoir A, Salmonella spp. were not isolated from carcases. The prevalence of E. coli on control carcases was 92.9% compared with 9.8% for hot water and 12.5% for SANOVA treated carcases. The mean log(10) E. coli concentration for control carcases was 0.89 cfu/gram, compared with -0.83 cfu/gram from hot water and -0.75 cfu/gram from SANOVA treated carcases. The mean log(10) TVC for control carcases was 4.06 compared with 1.81 cfu/gram for hot water and 2.76 cfu/gram for SANOVA treated carcases. At Abattoir B, the prevalence of Salmonella on control carcases was 16% compared with 2.7% for hot water and 7.0% for SANOVA treated carcases. The prevalence of E. coli on control carcases was 69.3% compared with 22% for hot water and 30% for SANOVA treated carcases. The mean log(10) E. coli concentration for control carcases was 0.45 cfu/gram, compared with -0.65 cfu/gram from hot water and -0.60 cfu/gram from SANOVA treated carcases. The mean log(10) TVC for control carcases was 3.00 cfu/gram compared with 2.10 cfu/gram for hot water and 2.53 cfu/gram for SANOVA treated carcases. The reductions in prevalence and mean log(10) concentrations in the present trial were all found to be statistically significant and indicate that carcases decontamination with either hot water or SANOVA are effective risk management options immediately available to the pork industry.