Prevalence and Risk Factors for Salmonella spp. on Pig Carcass, Before and After Chilling, in Brazil

The Brazilian Ministry of Agriculture, Livestock and Food Supply conducted a microbiological baseline study to determine the national prevalence of Salmonella in pig carcasses, and characterize the contamination risk according to the abattoir size under federal inspection in 2014-2015. All establishments were size-classified according to their slaughtering capacity per day. Sample weights were defined to increase the external validity of data. Samples were collected after the random selection of two half-carcasses from 76 slaughterhouses, one at the pre-chilling stage and the other at least 12 h after chilling. A total of 1544 samples were analyzed in official laboratories using Vidas SLM and SPT systems; for positive samples, we used the ISO 6579:2014. The results revealed that 10.00% (CI 7.50-13.22) of the pre-chilling carcasses tested positive for Salmonella spp. The medium-sized establishments exhibited the highest prevalence (18.51%). National and international market establishments had prevalences of 17.43%, and 9.05%, respectively. For carcass samples collected after chilling, the estimated prevalence was 4.58% (CI 3.13-6.65), with the highest prevalence recorded in the medium-sized establishments (7%), and values of 12.25% and 3.5% in the NM and IM, respectively. The information and knowledge thus acquired may support the further investigation and evaluation of surveillance programs, improving food safety.