Salmonella

Salmonellosis is an infection of the digestive tract, caused by a group of bacteria called Salmonella. It does not include infection with the types of Salmonella that cause typhoid and paratyphoid fever.

Salmonella bacteria are found in the gut of humans and many wild and domestic animals such as birds, mammals and reptiles.

In Australia, most Salmonella infections occur after eating contaminated food or sometimes after contact with another person with the infection.

Symptoms

The symptoms usually include:

• diarrhoea
• abdominal pain
• fever
• nausea
• vomiting
• headaches.

Sometimes the diarrhoea can contain blood and mucus.

Symptoms usually start from 12 to 36 hours after a person is exposed to the bacteria, but can begin after 6 hours. Most people are sick from 4 to 7 days, sometimes longer. Dehydration can be a complication in young children and the elderly.

Rarely, the infection can spread into the bloodstream or other parts of the body. This can be very serious and require hospital treatment.

How salmonellosis is spread

People become unwell after swallowing bacteria. Usually this happens after eating inadequately cooked food, by cross-contamination or person-to-person spread.

This can be by:

• eating contaminated undercooked meat (most commonly chicken)
• eating contaminated raw or undercooked eggs
• eating food (that won’t be cooked further) after it has been cross contaminated with Salmonella from raw foods (especially meats, poultry and eggs), e.g. using contaminated kitchen utensils such as knives or cutting boards, or when an infected food handler touches the food
• handling raw meat and pet meat
• handling animals, including chickens and other birds, tropical fish and reptiles
• drinking water that has been contaminated, usually by animals or sewage.

Salmonella can also be spread from one person to another via the hands of someone who is infected, or through contact with their faeces.

Who is at risk of infection

Salmonella can infect anyone. However infants, the elderly and people with weak immune systems are more likely to have severe illness.

Diagnosis

Salmonellosis is usually diagnosed by laboratory testing of a faeces (poo) sample.

Treatment

Most people usually recover with rest and extra fluids. Antibiotics are not usually required but may be recommended by doctors in complicated cases.

Prevention

People with symptoms should not prepare food for others, or care for patients, children or the elderly. Hand washing is a very effective way of preventing cross-contamination and person-to-person spread of Salmonella.

Hands should be washed with soap and running water for between 10 to 15 seconds:

• before preparing food
• between handling raw and ready to eat food
• before eating
• after going to the toilet or changing nappies
• after handling animals
• after working in the garden.

Safe food handling and storage

Adopting safe food handling and storage techniques can effectively prevent the spread of Salmonella.

Remember to follow these food safety rules:

• keep food preparation areas and utensils clean
• use separate cutting boards and utensils when preparing raw foods and ready-to-eat foods
• thoroughly cook all raw food, particularly poultry and eggs
• avoid using cracked or dirty eggs
• in the fridge, keep raw foods on a lower shelf than ready-to-eat foods to avoid cross-contamination
• keep food below 5°C or above 60°C to prevent growth of bacteria.
• reheat food until the internal temperature is at least 75°C
• wash raw fruit and vegetables before eating them
• only defrost food in a fridge or by using a microwave, don’t leave it on the bench
• dry dishes with a different dish cloth to that used for wiping hands or kitchen surfaces and wash dish cloths regularly.

Pets and animals

Be aware that pets and other animals can carry Salmonella. Chickens, tropical fish and reptiles pose a particular risk for young children and infants.

Staying home from school or work

People with Salmonella infections should not attend school or work until their diarrhoea has completely stopped.

Children should not attend childcare until they have been free of symptoms for at least 24 hours. People who work at healthcare facilities, childcare centres, schools and food handlers should not work until they have been free of symptoms for at least 48 hours.

More information

Salmonella is a notifiable condition. For more information on Salmonella infections contact your doctor or call the Health Protection Service, Communicable Disease Control Information Line during business hours on 02 5124 9213.