A bacterium carried on skin and in noses that can produce a heat-stable toxin in food and cause rapid-onset illness.
A bacterium carried on skin and in noses that can produce a heat-stable toxin in food and cause rapid-onset illness. Staphylococcus aureus is a bacterium commonly found on the skin and in the nose and throat of healthy people. It causes food poisoning not by infection but by producing a toxin in food when it is allowed to grow. The toxin forms when contaminated food is left in the temperature danger zone, and importantly the toxin is heat stable, meaning normal cooking or reheating will not destroy it once it has formed. Symptoms come on quickly, usually within one to six hours of eating the affected food, and include sudden nausea, vomiting and abdominal cramps. Illness is generally short lived, often resolving within a day. Because the toxin survives heat, prevention depends on stopping the bacteria from growing in the first place rather than trying to cook out the hazard. The main way Staphylococcus aureus gets into food is through food handlers touching ready-to-eat food with bare hands, especially if they have cuts, sores or skin infections. Australian food businesses control it through good personal hygiene: thorough handwashing, covering cuts and wounds with waterproof dressings, and minimising bare-hand contact with ready-to-eat food. Because the toxin forms in the danger zone, keeping food cold or hot and limiting time at room temperature is essential. Foods that are handled a lot after cooking and then held warm, such as prepared meats, sandwiches and desserts, are typical risks. Staff who are unwell or have skin infections on their hands should be kept away from handling ready-to-eat food. A sandwich hand with an uncovered cut on their finger prepares a large batch of sandwiches, which are then left in a display for several hours at room temperature. Staphylococcus aureus from the cut multiplies and produces its toxin in the warm sandwiches. Customers who eat them feel sick within a couple of hours. Covering the cut, wearing gloves and keeping the sandwiches chilled would have prevented the illness.
Frequently asked questions
How does Staphylococcus aureus cause food poisoning?
It produces a toxin as it grows in food left in the temperature danger zone. It is the toxin, not the live bacteria, that makes people sick, and symptoms come on quickly.
Can cooking destroy the toxin?
No. The toxin is heat stable and survives normal cooking and reheating. This is why preventing the bacteria from growing is the only reliable control.
How does the bacterium get into food?
Most often from food handlers touching ready-to-eat food with bare hands, especially if they have cuts, sores or skin infections, since the bacterium lives on skin and in the nose.
How quickly do symptoms appear?
Very quickly, usually within one to six hours of eating the affected food. Symptoms include sudden nausea, vomiting and cramps and typically resolve within about a day.
How can a business prevent this type of food poisoning?
Enforce good hand hygiene, cover all cuts with waterproof dressings, minimise bare-hand contact with ready-to-eat food, keep staff with skin infections away from food, and control temperature and time.
