High diversity of salmonella serotypes found in an experiment with outdoor pigs

Summary

Little is known about the risk of Salmonella infection in outdoor pig production, but seroprevalence data has indicated a higher occurrence of Salmonella in outdoor production systems than in conventional indoor systems. This is perhaps due to the increased exposure to the surrounding environment including contact with wildlife. An unexpected high diversity of Salmonella serotypes, as e.g. S. Uganda and S. Goldcoast, which are not normally isolated from pigs, was detected in connection with an experimental study on transmission of Salmonella in outdoor organic pigs. In order to elucidate the potential source of the different Salmonella serotypes, a small-scale examination of wildlife was performed. Salmonella was not detected in any of a total of 22 rats, mice and shrews or in 21 birds (mainly crowbirds).
The unidentified source of these Salmonella serotypes implies inadequate control possibilities and may therefore pose a problem for outdoor pig production in terms of food safety.