Salmonella prevalence in market weight pigs before and after shipment to slaughter

Samples commonly used for microbiological culture of subclinical Salmonella infection in market weight pigs include fecal material, mesenteric lymph nodes, cecal contents, rectal contents, and rectal swabs. In epidemiologic investigations, collection of abanoir samples offers certain advantages over farm collected samples. Sampling at slaughter offers the advantage of a wider range of sample types. For practical reasons, samples collected on the farm for microbiological culture are usually limited to fecal samples, whereas slaughter samples can include lymph node and higher gut contents. The ease of collection at the slaughter plant facilitates sampling a large number of herds. Detection of Salmonella in slaughtered pigs is also a useful indicator of risk to pork safety, because slaughter processing is the primary point where direct risk of entry into the food chain exists. However, it is possible that pigs may become infected during transportation and lairage. Further, it is possible that pigs harbor Salmonella while on the farm, but they do not shed the organism into feces. The stress of events iromediately pre-slaughter may then induce these non-shedding infected pigs to begin shedding