In contrast to the 'infection' type of food-poisoning caused by salmonellae, this is a 'toxin' type—i.e. it is due to the ingestion of preformed toxin, not to any action of the organisms themselves upon the patient. Milk may be contaminated with Staphylococcus aureus from cows or from human beings, so cream-filled cakes and other foods containing uncooked milk products are prominent in the literature of this disease.
Cooks with staphylococcal finger infections may infect various other 'culture media' which are left to stand in a warm room or are 'warmed up'. Multiplication may also occur inside tins of food. For example, one outbreak was traced to the following sequence of events: In a certain factory tins of vegetables were placed in cold water immediately after they were sealed, in order to cool them down before labeling; the cooling process produced a partial vacuum in the tins, and one of them had a small leak, through which it sucked in some of the water; the worker responsible for lifting the tins out of the water had boils on her arms and had contaminated the water with Staphylococcus aureus; labeling sealed the small leak, and the staphylococci were left to multiply in an apparently normal sealed tin.
Once formed, the staphylococcal enterotoxin is more heat-resistant than the organism itself, and will even withstand boiling for a short while. Many of the Staphylococcus aureus strains that have been shown to cause food-poisoning belong to a small number of types in phage-group III .
Vomiting, which may be violent, comes on within 2 to 6 hours of eating the food.
Diarrhea often follows.
The patient may be prostrated and usually has abdominal pain.