Salmonella

What is salmonella?

Salmonella is the second most commonly reported cause of bacterial infectious intestinal disease in Scotland after campylobacter, with approximately 800 cases reported each year. Most salmonella infections occur after eating contaminated food or water or after contact with another person or animal with the infection.

• Download the FSS Fact Sheet — salmonella

What happens when you get infected by salmonella?

Common symptoms of salmonella poisoning include:

• diarrhoea
• stomach cramps
• nausea
• fever
• vomiting

Symptoms usually develop between 12 and 72 hours after becoming infected and usually last 4-7 days and clear up without treatment. People with severe or prolonged symptoms should consult a doctor.

Those who have a greater risk of becoming severely ill with food poisoning caused by salmonella are children under 5 years, the elderly and those with weakened immune systems. 

How is salmonella spread?

Salmonella bacteria typically live in animals, such as chicken, cattle, pig, reptiles, and human intestines and are shed through their faeces. Illness caused by salmonella can occur through a number of routes including contaminated food, environmental exposure (such as contaminated surface water), or transmission from infected animals. Foods commonly associated with the transmission of salmonella and cases of food poisoning include:

• raw meat
• poultry
• raw eggs
• dairy products

Salmonella bacteria can be spread during the slaughter and processing of meat. Other foods like fresh produce (i.e. salads, fruit and vegetables) can become contaminated through contact with animal and human faeces. 

Salmonella bacteria can be spread from pets such as reptiles, cats and dogs to people. They can also be spread from person to person through poor hygiene.

How to prevent getting infected by salmonella

In the kitchen, salmonella can spread by improper handling and cooking of food. This can happen by eating contaminated food such as undercooked pork and poultry meat, dairy products made from unpasteurised milk, chocolate or raw fruit and vegetables. Salmonella can also spread by eating other food items that have become cross-contaminated by poor food hygiene after handling raw meat or other contaminated foods. Raw pet food could also spread salmonella, please read our advice about the safe handling of it.

Another way it is spread is from another person infected with salmonella — an infected person can pass the infection on to others fairly easily when hand hygiene is poor. Make sure you wash your hands thoroughly with warm water and soap:

• before prepare and handle food
• after going to the toilet
• after touching raw meat
• after contact with animals

You can see how to keep your food and kitchen safe by following the 4Cs:

• Cleaning
• Cooking
• Chilling
• Cross-contamination

Under the microscope — control programmes for salmonella

During the late 1990s, when vaccination against salmonella enteritidis was introduced in the poultry industry, there was a 37% decrease in the number of cases of salmonella poisoning in Scotland. However it remains an important pathogen and is responsible for a large number of outbreaks each year, especially from eggs originating from unvaccinated flocks. Follow our advice on handling and storing eggs.

National control programmes have been established in the UK to reduce the prevalence of salmonella in poultry and pigs at primary production level. They cover farm animal species which present a potential risk of transmitting salmonella and other zoonotic agents to humans.