11/01/2016 3:51 PM AEDT | Updated 15/07/2016 12:51 PM AEST

Salmonella Explained: How Putting Eggs In The Fridge Affects Your Risk Of Catching The Deadly Bacteria

Dominic O'Brien / Fairfax Media

Shoppers are pressuring Supermarkets Coles and Aldi to store their eggs in the fridge after farming lobbyists and some experts said the practice reduced the risk of deadly salmonella poisoning.

The authority on egg safety however, does not agree, with Food Standards Australia New Zealand maintaining temperature is not a factor in spreading salmonella as long as eggs aren't cracked or dirty.

So what's best practice? How can salmonella be avoided and should you refrigerate your eggs? Here's everything you need to know about salmonella and eggs.

What's spurred this debate?

Victorian Farmers Federation president Brian Ahmed last week told The Age egg refrigeration in supermarkets was the "missing link" in the food safety chain.

"It should be treated exactly like raw meat – don't look at an egg any different way," Ahmed told The Age.

A social media response has ensued, with people praising Woolworths for storing eggs in the fridge while calling on Coles, IGA and Aldi to uniformly take up the practice.

Why can Australian supermarkets be allowed to sell unrefrigerated eggs?

Food Standards ANZ Acting chief executive officer Peter May told The Huffington Post Australia refrigeration was not the key to safe eggs.

"An egg's shell, membrane and the egg white all form a barrier designed to stop food poisoning bacteria from contaminating the inside of an egg," May told HuffPost Australia.

"Whole un-cracked eggs aren’t required to be refrigerated at retail because salmonella must first cross the physical barriers of the shell and membranes, and tolerate the hostile conditions of the egg white before it can enter the yolk and grow.

"There is no food safety reason to require whole eggs to be refrigerated, however retailers may choose to refrigerate eggs for their own reasons for example, to maintain quality of the egg such as firmness of the yolk or reduce spoilage."

But supermarkets in the U.S. and parts of Europe have to refrigerate their eggs.

"Unlike many other countries, the types of Salmonella that can contaminate the inside of eggs as they are formed in the bird are not present in Australian laying flocks," May said.

What exactly is salmonella?

It's a type of bacteria that can cause gastroenteritis.

How do you get infected?

It can be ingested with dirty water or food such as eggs, milk, meat or poultry.

It's also often present in animal faeces and dirt, and can spread from person to person.

What does Salmonella do to you?

While salmonella can be deadly, the severity depends on the number of bacteria you ingest, your age and your general health.

Symptoms can appear anywhere form six hours to three days after ingesting the bacteria and include diarrhoea, headache, stomach cramps, nausea and vomiting.

Eggs are one of the riskier foods, how do you reduce your risk?

May said Australian salmonella poisoning cases usually related to raw eggs.

"Evidence shows that food poisoning outbreaks associated with eggs in Australia have been mostly due to uncooked or lightly-cooked foods containing contaminated raw egg such as sauces and desserts," May said.

"Factors that may have contributed to outbreaks included cross-contamination during food preparation like the transfer of salmonella from the surface of the egg to other surfaces and storage of the food containing raw egg at temperatures that would permit growth of Salmonella.

"Raw egg products like raw egg mayonnaise are considered high risk and they do require refrigeration. This is because pathogens may contaminate the egg pulp when the egg is cracked."

And in general?

  • Cook meat until the juices run clear.
  • Check all eggs for cracks or dirt.
  • Always refrigerate homemade mayonnaise or any other raw egg product.
  • Do not drink unpasteurised milk.
  • Wash hands regularly and keep food preparation areas clean.