KEY POINTS:
Do not just crack open a dirty egg - wash it first.
That is the advice from a food safety official after traces of the food-poisoning bug salmonella were found on shells.
As many as 200 people in Australia have been afflicted by food poisoning linked to foods containing raw egg: tartare sauce, chocolate mousse and a caesar salad dressing.
In New Zealand, nine eggs with salmonella bacteria have been found by the Institute of Environmental Science & Research in a pilot study of 514 retail cartons or trays.
But none of the eggs' contents tested positive for the bacteria and the study suggests the risk to consumers in New Zealand is low.
Salmonella food-poisoning typically causes diarrhoea, abdominal pain, headache and nausea and sometimes fever, usually for two or three days. Dehydration or blood poisoning can occur in some cases.
The Food Safety Authority's principal adviser on public health, Dr Donald Campbell, says Britain had a serious problem with salmonella inside eggs, but this had never been detected in New Zealand.
"Obviously if there's faecal contamination of the shell you should wash them before you use them," he said, adding that this could be done in cold, running water.
But the Egg Producers Federation's executive director, Michael Brooks, said washing such eggs risked forcing the contamination inside them because the shell was porous. Instead, contaminated eggs - which were rare - should simply be wiped with a damp cloth.
