Egg washing temperature question

[K0k0shka]

Here's another commonly given piece of advice I've always questioned. You often see people recommending to wash eggs in water that's warmer than the egg, the logic being that colder water will cause the insides of the egg to shrink a little, thus sucking in bacteria from the shell surface in through the pores, contaminating the egg. And warmer water will cause the insides to expand, pushing out instead of sucking in. But given that we tend to regard raw eggs as unsafe for bacterial reasons to begin with, and need to cook them thoroughly to kill salmonella and whatnot, wouldn't the cooking process also kill whatever it was that the egg sucked in from the surface? You're going to be nuking the egg, why does it matter if it sucked a couple extra bacteria in. The only scenario I can imagine this being remotely relevant is if you don't immediately cook the eggs after washing, but are rather storing them after washing. So, presumably, the sucked in bacteria sit inside the egg for longer and can multiply. But again, even that is unlikely, as washed eggs need to be refrigerated, and refrigeration stalls/stops bacterial development, so not much will be happening until you nuke the egg by cooking it. And the majority of the time when people wash eggs, is because they are about to cook them.

So, can somebody more science-versed explain why I should care about washing temperature for eggs I'm about to cook?

 

[TooCheep]

Actually, the overwhelming most common time to wash eggs in the US is at the egg farm/factory. Even for people that don't wash home-grown eggs immediately, they may not wash them at all before opening them if they are clean to the naked eye.

Question: On what do you base your statement that people wash eggs just before opening? I would never put a poop-covered egg in an egg container, particularly since I reuse that container as new eggs come in and healthy poop is always high in bacteria.

As for the concept of bacterial infiltration problems washing in cold water. It is actually trivial to test. Take some dyed cold water and wash the egg in it. Then take some dyed warm water and do the same. I'd leave them both in the water for a while (10min?) just to exaggerate the effect. Note- I have not done this, just proposing a simple experiment.

Our bodies have defenses against bad bacteria, but it can be overwhelmed at high doses. Eggs are often used in medicine as a favorable growing environment to multiply bacteria and viruses.

A fresh, well-protected egg can be eaten raw. In some percentage of eggs, they are not cooked long enough or at high enough temperatures to kill all of the bacteria. I prefer well done scrambled eggs and hard-boiled eggs, but many eat soft-boiled eggs, runny scrambled eggs/omelets, sunny-side up, etc.

All of these points are to minimize the chance of food poisoning. Any single or even small amount of poor practice won't necessarily cause problems. It is just one of several easy steps (cleaning immediately if needed, thorough cooking and minimizing infiltration) to minimize problems, particularly in large populations.
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So do what you want. However, ignoring safety protocols without understanding the risk and/or being able to demonstrate that they are unnecessary should be done at your own risk only.

 

[K0k0shka]

Thanks for the reply. I'll answer each question/segment separately since there's a lot there.

Actually, the overwhelming most common time to wash eggs in the US is at the egg farm/factory.

Yes, grocery store eggs in the US are pre-washed, but I'm not talking about that. I'm specifically asking about backyard eggs.

Question: On what do you base your statement that people wash eggs just before opening? I would never put a poop-covered egg in an egg container, particularly since I reuse that container as new eggs come in and healthy poop is always high in bacteria.

I base that on my own practices (dating back to my family's practice growing up and everybody around us), as well as years of reading through BYC and other forums/groups. The overwhelming majority of people wash backyard eggs before cooking. Occasionally, somebody less experienced will ask about washing before storage/refrigeration, and the advice that's given is pretty much always that fresh backyard eggs don't need to be washed after collecting because they still have their protective bloom (unlike pre-washed store eggs), but that they should be washed before cooking. Also people point out that they only wash eggs right after collection if they are very poopy (no we don't put fresh poop in our storage containers!) and after washing the dirty ones, they refrigerate them. But most of the time the eggs don't have visible poop on them and thus don't need immediate washing.

As for the concept of bacterial infiltration problems washing in cold water. It is actually trivial to test. Take some dyed cold water and wash the egg in it. Then take some dyed warm water and do the same. I'd leave them both in the water for a while (10min?) just to exaggerate the effect. Note- I have not done this, just proposing a simple experiment.

I'm not questioning whether bacteria gets in or not, so I don't need to test that. I assume that some probably does. What I'm asking is whether the bacteria that potentially gets in, poses any safety threat to me, if I'm going to cook the egg thoroughly anyway.

Our bodies have defenses against bad bacteria, but it can be overwhelmed at high doses. Eggs are often used in medicine as a favorable growing environment to multiply bacteria and viruses.

Like I said, I cook my eggs thoroughly, so there would be no overwhelming high doses of bad bacteria here.

A fresh, well-protected egg can be eaten raw. In some percentage of eggs, they are not cooked long enough or at high enough temperatures to kill all of the bacteria. I prefer well done scrambled eggs and hard-boiled eggs, but many eat soft-boiled eggs, runny scrambled eggs/omelets, sunny-side up, etc.

A fresh, well-protected egg can still carry salmonella, because salmonella lives inside the chicken's body and is transferred to the egg as it's being formed, before the shell develops around it. So the egg comes out with salmonella already inside it, and its outward cleanliness, freshness or protection won't help guard against salmonella. That's why I said cooking thoroughly, and my question and use case scenario only applies to thoroughly cooked eggs. People who eat raw/undercooked eggs are a whole separate scenario that I'm not addressing or interested in, in the context of my post.

So do what you want. However, ignoring safety protocols without understanding the risk and/or being able to demonstrate that they are unnecessary should be at your own risk only.

The basis of my question is whether washing eggs in warm water even IS a safety protocol. I follow the rest of the safety protocols - I wash my eggs before cooking, I cook them thoroughly, and regard raw eggs as contaminated by default, so I wash all utensils/hands/surfaces thoroughly after they've touched raw egg. So I'm checking all the obvious safety boxes. What I need to know is whether egg washing temperature is a safety issue at all, or if it's just something that makes sense logically and is being passed around as advice, but isn't actually scientifically sound or practically necessary.

 

[TooCheep]

The basis of my question is whether washing eggs in warm water even IS a safety protocol. I follow the rest of the safety protocols - I wash my eggs before cooking, I cook them thoroughly, and regard raw eggs as contaminated by default, so I wash all utensils/hands/surfaces thoroughly after they've touched raw egg. So I'm checking all the obvious safety boxes. What I need to know is whether egg washing temperature is a safety issue at all, or if it's just something that makes sense logically and is being passed around as advice, but isn't actually scientifically sound or practically necessary.

Sorry, I didn't interpret "nuked" as thoroughly cooked. As for whether cold/warm washes are important, you just waved off the most direct piece of evidence. Safety and security are rarely a yes-or-no situation, but rather a matter of degree. You do what you are comfortable with.

You can continue to thoroughly cook your eggs and hopefully will be fine, that you or anyone else using your eggs never under-cooks an older, infected egg, but a belt-and-suspenders approach is safer. I have personal experience using that scheme with pharmaceutical production, firearms and home security. All use this technique (aka: defense-in-depth) to minimize failures.

 

[K0k0shka]

As for whether cold/warm washes are important, you just waved off the most direct piece of evidence.

Which one was that? Sorry, there's a lot of text and I'm getting lost in all the separate points. I'm specifically looking for evidence that thoroughly cooking will not kill the surface bacteria that gets in. Not evidence whether or not bacteria gets in in the first place. But specifically whether thorough cooking makes up for the washing temperature. And I'm asking purely out of curiosity, because I like to know how and why things happen, on a scientific level - it's just cool to know.