HEALTH authorities say it could be weeks before they trace the cause of a mass salmonella poisoning outbreak linked to a Brisbane catering company.
Although Piccalilli Catering has blamed eggs used for making mayonnaise on the outbreak, Metro North Public Health Unit director Susan Vlack said “three or four” suspected contaminants were being looked at.
“We don’t have any definite proof that it is the eggs,” Dr Vlack said. “We don’t have the results in to be able to say one way or the other. There are still a number of possibilities. It might take two, possibly three, weeks.”
The outbreak has been linked to the death of 77-year-old Judy Anderson and more than 220 people falling ill. Eight people so far have required admission to hospital, including Ms Anderson, who died of heart complications after developing salmonella poisoning. Those affected attended up to 40 Melbourne Cup functions.
Dr Vlack said hundreds of tests were being processed to trace the source of the outbreak.
Piccalilli Catering has moved from the premises where the food was prepared for the Melbourne Cup functions into new facilities and is still operating.
“The Brisbane City Council has gone through all their operations with a fine-tooth comb,” Dr Vlack said. “Food authorities do not have concerns with the company continuing to operate because lots of measures have been put in place. We’re confident that they can continue to operate safety.”
Piccalilli Catering has implicated eggs sourced from a Brisbane-based fresh food wholesaler in the outbreak. Infectious disease specialist Mike Whitby said the salmonella organism was found in the bowels of many animals, including chickens and other birds.
“It can be acquired from meat products and it often occurs in foodborne outbreaks,” Professor Whitby said.
He said the bacteria were sometimes found on the outside of chicken egg shells, not on the inside.
“In many egg products where it’s cooked, that will kill the salmonella,” Professor Whitby said.
“The important thing about mayonnaise is that it has raw eggs in it, so it’s not cooked. If you’re making a commercial quantity, you’d only need one or two of those eggs to have salmonella on them to spread throughout the entire batch.
“When someone cracks the egg, they may get salmonella in the egg material and that goes into the mayonnaise, or if they’re separating the yolks from the whites, they may get their fingers contaminated. It’s important for people preparing food to wash their hands in between touching eggs.”
Professor Whitby said providing food hygiene standards were high, the outbreak may be “bad luck”.
“There may be no fault at all on the commercial egg supplier or on the catering company,” he said. “I’m not sure it was preventable.”
Dr Vlack said between 3000 and 4000 cases of salmonella were reported in Queensland annually.