Prevalence of Salmonella spp. after hot-water decontamination of finishers slaughtered in a Danish abattoir during 2004-2008

In Denmark, pigs from herds with unacceptable high levels of Salmonella spp. (level-3 herds) or herds with multi-resistant Salmonella Typhimurium DTI04 are obliged to undergo sanitary slaughter to secure food safety. Since 2001, carcasses from such herds undergo hot-water decontamination (HWD) in one plant belonging to the largest slaughterhouse company in Demnark. On each day of HWD, swab samples are taken from the surface of five heat-treated carcasses. These samples are analysed qualitatively as a pooled sample for Salmonella. Further I 0 swab samples are collected and analysed individually for E. coli (quantitatively). We present surveillance data from mid-February 2004 to December 2008. Moreover, we identifY risk factors for Salmonella after HWD. Salmonella was found in 2.6% of the pooled samples corresponding to an individual carcass prevalence of0.9%. On days where E. coli exceeded the acceptable limit (i.e. ~I out of 10 samples had levels \u3e320) there was a tendency towards higher probability of finding Salmonella compared to other days (8.3% versus 2.5%; p~0.28). These data show that HWD is an effective risk-reducing way of dealing in practice with slaughter pigs from herds with higher risk of Salmonella