I have a question additional to this question How does salmonella get into eggs. This tells me that salmonella is mostly found on the shell of an egg. However, eggs are treated (typically washed) such that most egg shells do not contain any salmonella anymore.

I eat eggs which I get from my mother-in-law who has her own chickens, so these eggs are not 'treated'. I was wondering a few things:

  • What is the risk that these eggs contain salmonella? Is this risk negligible?

  • Should I use supermarket eggs to make food with raw eggs in it, for example chocolate mouse, and only use these eggs for food which is heated?

  • If there is a risk, how should I clean the shells? (using hot water is not an option for eggs, of course).

A related question might be Is it safe to eat raw eggs?. The answer seem to be yes, but here it also seems that it is about 'supermarket eggs'.

  • Check with you local government food safety people. The answer for this is different in each country
    – TFD
    Commented May 13, 2012 at 22:13

3 Answers 3


If you need the eggs raw, you could submerge them in boiling water for 5 sec. That would kill any bacteria on the shell and the egg would still be raw inside. Put the eggs in cold water right away to prevent the egg from heating up by the residual heat in the shell. I have tried this many times and the eggs do not cook. If you are serving the eggs to very young children, pregnant women or someone who are sick, you should buy pasteurized eggs instead. But normally it's safer to eat eggs from chickens you raise, than the ones from a factory, because they are more healthy and their immune system is well developed enough to kill the salmonella itself.


The danger of bacterial contamination is much lower in home laid eggs than in commercially produced eggs exactly because of the washing process that eggs go though in the US.

See the accepted answer to this question:
How long can I keep eggs in the refrigerator?

Eggs are naturally laid with a protective coating on them that will keep out bacteria. An egg keeps for a long time in a nest after all.

Commercially produced eggs are washed- I assume for cosmetic reasons- which destroys this coating and makes the porous egg shells very susceptible to bacteria.

You should discard eggs that have damaged shells but other than that you can consider your mother-in-laws eggs much safer than any you could get at the supermarket.

  • 3
    There is a second way of salmonella transmission to eggs: from the ovaries of an infected hen, before the eggshell has been formed. Wikipedia says that the probability of this happening is 3% with artificially infected hens and even lower "in the wild", but I guess that the relative safety is also dependent on how well your mother-in-law can recognize an infected hen in time (but then again, infection rates in a backyard coop are probably lower than in egg mass production).
    – rumtscho
    Commented May 14, 2012 at 10:39
  • 1
    I always wash the eggs from the neighbor's chickens in soap and warm water, right before breaking the shell and using them. Commented May 14, 2012 at 22:30
  • 3
    Eggs are washed because chicken poo is not a desirable additive to most foods.
    – Marti
    Commented May 18, 2012 at 17:14
  • 1
    @Marti- Chickens don't defecate in their nests if they have a choice. Eggs are usually pretty clean. Commented May 18, 2012 at 18:12

Your risk is likely lower than that of Americans, as your user info lists you being in the Netherlands.

European chickens are often innoculated against salmonella, which brings down the risk significantly. I would ask your mother-in-law to be certain if this is the case, especially if she's in another country (eg, if you're near the Netherlands / Belgium border).

As for supermarket eggs: if they're sold as unrefrigerated, then they'd have also been from innoculated chickens, and still have their bloom intact. The risk may be slightly increased from your supermarket eggs, as they're likely slightly older, and likely have been raised in more crowded conditions.

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