Salmonella in pigs

What is salmonella?

Salmonella is a group of bacteria, widespread within the human and animal populations. It multiplies within the intestine and causes enteric disease. Salmonella can survive for long periods of time within faeces, dust and wildlife vectors, such as rodents. Specific serotypes relevant to the pig industry include salmonella choleraesuis, salmonella typhimurium and salmonella derby.

How does the disease spread?

Piglets and early growers are more commonly infected with clinical disease, which is usually short-lived. However, subclinical infection can persist for longer periods of time. It can be spread through direct contact with an infected pig, ingestion of contaminated feed, water and faeces and wildlife vectors, including rodents, birds and cats.

What can be done to reduce the risk?

High levels of salmonella at the abattoir can increase the risk of zoonotic spread of salmonellosis from cross-contamination between carcases. We have been working closely with the pig industry for several years to reduce salmonella levels, from the farmgate to the processor. Key measures, such as biosecurity and thorough cleaning and disinfection at all stages of production, are vital in ensuring that the risks are reduced. See the useful links section at the bottom of this page for more information.

What are the main signs of infection and how can it be prevented?

  • The main clinical sign is diarrhoea, but other signs can occur. Please consult with your vet for more information
  • The severity of salmonella infection depends on the number of salmonella bacteria present. The focus should be on decreasing the level of salmonella in the environment and to lower the spread
  • Biosecurity is an important aspect of control and prevention and more information can be found under the biosecurity section  of the website


EU legislation requires abattoirs to identify farms where pigs show regular salmonella contamination.

The Food Standards Agency (FSA) closely monitors all abattoir test results and abattoirs will have to agree an action plan with the FSA if target levels are exceeded. The accepted level of incidence is 3 positives out of 50 samples over a 10-week period. This is the equivalent of 6% salmonella prevalence. 

Useful links