Tracking of Salmonella spp. Contamination Routes in a Pork Production Chain in Brazil

Introduction: Salmonella spp. is a relevant foodborne pathogen associated to a diversity of cases and outbreaks related to the consumption of pork products. Considering the characteristics of swine production, Salmonella spp. can be present in the pork chain since the beginning of production, in piglets farms, until the processing of final products in slaughterhouses.

Purpose: This study aimed to identify the main contamination sources of Salmonella spp. in pork production chain in Brazil.

Methods: Six lots of piglets produced in different farms were tracked until their slaughtering, being samples collected from piglets production farms (n=662), pigs finishing farms (n=636) and slaughterhouse (n=270). The samples (feed, water, floor, feces, carcasses, lymph nodes, utensils, equipment) were subjected to Salmonella spp. detection according to USDA protocol. Isolates were serotyped and subjected to pulsed-field gel electrophoresis (PFGE) after macrorestriction with XbaI.

Results: Salmonella spp. was detected in 160 (10.2%) samples: 32 (4.8%) in piglets production farms, 88 (13.8%) in pig finishing farms (in both cases mainly in feed, floor and feces), and 40 (14.8%) in slaughterhouse (mainly in feces, jowls and mesenteric lymph nodes). Among the 210 Salmonella spp. isolates, Salmonella Typhimurium was the most prevalent (101). PFGE allowed the identification of a continuous entrance of novel Salmonella spp. pulsotypes in this food chain, as well as the feed and feces as relevant sources of contamination.

Significance: Salmonella spp. was confirmed as a relevant foodborne pathogen in the pork production chain. The identification of the exact contamination routes was important to lead proper procedures to control Salmonella spp. in this food chain.