Eggs. Aren’t they just great? Picture: Getty Images

Why don’t Europeans refrigerate their eggs?

A lot of curious Americans tuned in for the answer to that seemingly innocuous question, which was asked by a reader of Business Insider’s science team.

Because in the US, supermarket eggs are always refrigerated. You can read the full story behind why here, but essentially it’s because of differing views on salmonella.

So, in the US:

Eggs have to be washed before being packaged, because of fears of salmonella infection on the outside of the egg.

The washing solution has to be hot so dirty water doesn’t get drawn into the egg, because eggs are porous.

There is some evidence that washing the eggs weakens the shell, thereby actually making them more susceptible to salmonella infection. To combat this, clean eggs must be immediately moved to cooler rooms that maintain a temperature of 7C or lower.

And because they’re refrigerated, they have to stay that way until cooked, because sweating eggs can also draw contaminants inside the shell.

Whereas in the UK:

Eggs aren’t washed because of the possible increased risk (as stated above) of salmonella infection being transferred inside the egg.

Because they’re not washed and refrigerated, it also provides an incentive for farmers to maintain conditions that produce clean eggs.

And because they’re not washed (possibly weakening the shell) and refrigerated, they can be stored on shelves.

Also, a lot of EU farmers vaccinate their hens against the type of salmonella that can develop inside the egg before it’s laid.

So that seems pretty clear. Washed eggs should go in the fridge. But what about here in Australia, where there’s a requirement for farmers to wash eggs as in the US, yet it’s not unusual at all to see them stored on supermarket shelves, UK-style?

Adding to the mess is the likelihood whoever does the shopping in your house immediately whisks them into the fridge when they get home, right? Unless you got them from a picture-postcard farm on a Sunday drive, in which case they just seem more at home in a nice basket on the kitchen counter.

Confusion reigns. And getting it wrong can have a serious impact. According to Food Standards Australia New Zealand, eggs are responsible for about 13,000 cases of salmonellosis per year in Australia. In a 2009 risk assessment, it reported:

An economic valuation of these illnesses is an estimated total cost of $44 million to the Australian economy each year.

That helped form a proposal which was written into the Food Standards Code for both countries. It’s important the code isn’t a regulatory national industry standard. It’s up to individual states and territories as to the extent to which they enforce compliance.

But it answers the question as to whether Australian eggs should be kept in refrigerators or on shelves.

Here’s the quick version:

In Australia, eggs have to be washed and because there is little to no chance of interior contamination while eggs are forming, they can be kept on the shelf. However, if you want them to keep longer, it’s advised you take them home and put them in the fridge.

But if you’re wondering how Australia got to that point which sits a little confusingly between the US and the UK, it’s a longer story that began back in 2007…

Eggs and salmonella were officially newsworthy. Food Standards Australia New Zealand conducted a scientific assessment of the risks eggs posed to public health. That helped form a proposal which was written into the Food Standards Code for both countries. Picture: The Sun-Herald In the UK, Grade A hen eggs must not be washed. According to the Food Safety Authority of Ireland, the process may 'aid the transfer of harmful bacteria like salmonella from the outside to the inside of the egg'. It's thought that washing eggs weakens the shell. Picture: Getty Images European hens are vaccinated against the type of salmonella that in the US can see it pass into the egg while it is forming. That's also not seen in Australia. Partly because of this, FSANZ, in the new code it published in 2011, dismissed the option of forcing retailers to refrigerate eggs. It felt the cost of implementing this guideline was too harsh for retailers, given the risk in Australia could be effectively managed further up the production process. Picture: Getty Images It's still difficult to pin down the source of infection because of the way people at home and in food outlets use raw eggs - such as in mayonnaise, hamburger patties or macho morning health shakes. Whether you buy them off the shelf, out of the fridge, or at the farm gate, don't ever leave the raw product out where it can heat up beyond 7C. If you do feel the need to buy dirty eggs, Victoria's Better Health initiative advises against washing them. There's a chance you'll contaminate the egg by using dirty water, cloths, or water that's not hot enough which could result in it being sucked into the egg through tiny pores in the shell. Picture: Getty Images

And here’s some further reading:

FSANZ

Australia New Zealand Food Standards Code – Standard 4.2.5 – Primary Production and Processing Standard for Eggs and Egg Product

Proposal P310 Primary Production & Processing Standard For Eggs and Egg Products

Public health and safety of eggs and egg products in Australia

Australian Egg Corp Ltd

Code of Practice For Shell Egg, Production, Grading, Packing and Distribution

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