Two deaths in a hospital have sent panic waves among health officials who are investigating food poisoning as the cause.
The deaths of patients(men) are linked to listeria, a serious infection caused by eating food contaminated with the bacterium Listeria monocytogenes.
The traces of listeria were discovered in the kitchen of the Royal Adelaide Hospital
Two women who were also infected are recovering after being treated with antibiotics.
However, all four patients had been "in and out of a range of hospitals and will have consumed meat from a range of other sources", Dr Givney director of the state Health Department's communicable disease control branch said. The deaths "do not necessarily relate to the hospital in which the two men died".
Dr Givney said South Australia had "a history of problems" with processed meat.
"Listeria can be the last complication of a very complicated illness," Dr Givney said. "Nobody will say listeria didn't contribute to their deaths, but how much is an unanswerable question."
The listeria bacterium is commonly found in raw food, but most people are immune to the infection. Dr Givney said pregnant women and people with low immune systems were particularly susceptible, urging those most vulnerable to think carefully before eating foods such as raw seafood, cold cooked chicken and salads.
It was "possible we may never know the source of this listeria", he said.
"The problem is that listeria has got an extremely long incubation period ... trying to remember what you ate yesterday is hard enough, but trying to get that information from grieving families is a tough call."
This has made all hospitals take notice and review their food preparation methods and inspect kitchens.