Sock and Environmental Swabs as an Efficient, Non-Invasive Tool to Assess the Salmonella Status of Sow Farms

Salmonellosis is the second most reported gastrointestinal infection in humans after campylobacteriosis and a common cause of foodborne outbreaks in the European Union (EU). In addition to consumption of contaminated animal-based foods, such as poultry, beef and eggs, pork is an important source of human salmonellosis outbreaks; therefore, Salmonella (S.) control should start in the early stages of pig production. To be able to implement effective control measures to reduce the risk of pigs being infected by Salmonella, it is important to identify the serovars circulating on farm within the different stages of production, including as early as sow and piglet breeding. The aim of the present study was to assess the Salmonella status of sow farms either producing their own finishers or delivering piglets to fattening farms with a known high serological prevalence identified within the QS Salmonella monitoring system. Overall, 97 (92.4%) of 105 investigated piglet-producing farms across Germany tested positive in at least one sample. Salmonella was detected in 38.2% of the sock and 27.1% of the environmental swab samples. S. Typhimurium was the most frequent serovar. In conclusion, sock and environmental swab samples are well suited for non-invasive Salmonella detection in different production units in farrowing farms. To establish a holistic Salmonella control program, all age classes of pig production should be sampled to enable intervention and implementation of countermeasures at an early stage if necessary.