Salmonellosis

Last updated: 14 January 2008

What is Salmonellosis?

Salmonellosis is caused by infection with bacteria called Salmonella. In Australia, most Salmonella infections occur after eating contaminated food or sometimes after contact with another person with the infection.

What are the symptoms?

People infected with Salmonella commonly develop headache, fever, stomach cramps, diarrhoea, nausea, and vomiting. Symptoms often start 6-72 hours after infection. Symptoms usually last for 4-7 days, sometimes much longer.

How is it spread?

Salmonella is mainly spread to humans when they eat poorly cooked food made from infected animals (that is, meat, poultry, eggs, and their by-products). Spread by 'cross-contamination' occurs when Salmonella contaminates ready-to-eat food: for example, when food that will not be cooked further is cut with a contaminated knife or via the hands of an infected food handler. Salmonella can spread from person-to-person via the hands of an infected person. It can also be spread from animals to humans.

Who is at risk?

Anyone can get salmonellosis. Infants, the elderly, and people with poor immune systems, are more likely to have a severe illness.

How is it prevented?

Cooking
Thorough cooking of food kills Salmonella. Avoid raw or undercooked meat, poultry, or eggs. Poultry and meat - such as hamburgers, sausages, and rolled roasts - should not be eaten if pink in the middle.

Food handling
Because Salmonella can be carried on the hands, it is very important to always wash hands thoroughly after using the toilet and before preparing food. Hands should be washed with soap and water for at least 10 seconds, rinsed, and dried well. Particular attention should be given to the area under the fingernails and between fingers. Infected food handlers can shed large numbers of Salmonella. They should not handle or serve food until the diarrhoea has stopped and their stools test clear of Salmonella.

Temperature control
Poor food storage can allow Salmonella to grow. Refrigerated food should be kept at less than five degrees Celsius. Hot foods should be kept hot at above 60 degrees Celsius. Reheated foods should be quickly reheated until all parts of the food are steaming hot. Thawing frozen foods should be done in a fridge or microwave. The longer you leave food at room temperature the more Salmonella can multiply.

Food contamination
To prevent the contamination of food:

• store raw foods (such as meat) in sealed containers in the bottom of the fridge or freezer to prevent any fluid dripping or spilling onto other ready-toeat food. Cover all foods in the refrigerator and freezer to protect them from contamination
• wash hands immediately after going to the toilet or handling raw foods and before handling cooked or ready-to-eat food
• use different chopping boards, trays, utensils and plates when preparing raw foods and ready to eat food. If you have only one chopping board wash it well in hot soapy water before reuse
• thoroughly wash all dirt off any raw vegetables and fruits before preparing and eating them
• dry dishes with a different cloth to that used for wiping hands or bench tops; wash dish cloths regularly

How is it diagnosed?

To diagnose it, your general practitioner or local hospital will send a stool sample to a laboratory for Salmonella testing.

How is it treated?

Most people recover with rest and fluids. Some people may require hospitalisation. Antibiotics are sometimes recommended in complicated cases.

What is the public health response?

Laboratories are required to notify cases of Salmonella infection to the local public health unit. The public health units investigate clusters of casess to try and identify common links. Where a common food is implicated the NSW Food Authority will undertake a further environmental investigation and initiate control measures. Statistics on cases are used to help develop prevention strategies.

The NSW Food Authority is responsible for a range of food safety strategies to prevent salmonellosis and other food borne infections.