The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Eggs and Salmonella in Sourdough Recpes?

Mylissa20's picture

Eggs and Salmonella in Sourdough Recpes?

I just found a really delicious recipe I would like to try with my start, but I just realized that it calls for eggs in the 12 hour preferment.  I've never used eggs in sourdough before because I assumed I would kill my family with salmonella that way :)  Am I wrong?  I would love to try this recipe, so I'd appreciate some advice before I bake these up.

cranbo's picture

Uncooked, refrigerated eggs should not be left out at room temperature more than 2 hours, according to USDA Food Safety & Inspection Service guide

Leaving raw eggs in a starter @ room temp puts them in the "danger zone" for bad bacteria to grow. Funny, the same danger zone is exactly where yeast & sourdough bacteria thrive the most!

I suppose if the sourdough environment is acidic enough, you might be OK. I personally would avoid raw eggs in a starter. 

That said, I regularly use buttermilk in a rye soaker for years, which sits out at room temp overnight and have never had any problems...although the buttermilk is scalded.


yy's picture

does the recipe explain the rationale behind including eggs in the preferment? You could probably leave them out and add them only when you're mixing your final dough. I doubt that any yeast or enzymatic activity occurs on the egg itself that would affect flavor later. 

Mylissa20's picture

the preferment pretty much includes everything in the recipe, so I'm not sure it would be feasible to add the eggs later.  I think it would end up a big gloppy mess.  Is there a good way to knead in eggs?

G-man's picture

Let's see if I remember my food handler's training...


Salmonella bacteria die in ten minutes at about 165F, which google says is about 74C. They can be killed off if held for longer at lower temperatures. Once the bacteria are dead, they are of no risk to you. This needs to be the very clear part: There has to be huge concentrations of nearly raw surface area on the food you are eating. You can't catch salmonella from a rare steak. You CAN catch it from a rare hamburger. You can't catch it from a thoroughly cooked hamburger (165F, 74C). Most healthy adults in civilized countries have an immune system capable of fighting off the amounts of living salmonella found in your average cheeseburger.


For eggs, salmonella is usually found on the shells if it's present. If you aren't eating raw egg shells, you'll probably be alright. Even so, if you thoroughly cook the eggs (165F, 74C) you're killing all the salmonella. Since bread bakes to near the boiling point of water, assuming the acids in the sourdough starter don't kill it off, salmonella will be dead looong before it reaches your kids.



clazar123's picture

G-man,salmonella from egg shells is a problem to people, just from handling and transferring the bacteria to the person and surfaces around them. Any dough with raw egg contaminated with salmonella is a health hazard to anyone in that environment for a period of time. The person handling and kneading the dough has it deposited in finger/nail crevices and their person and clothing, they ingest and can transfer it for a number of days if infected and can become a carrier. The bread will become sterilized by the heat of the oven but the baker is not.

Unfortunately, we have many heritage recipes using raw egg product that should either be abandoned or made with carefully pasteurized eggs. Pasteurization can be done at home but it is tricky. Our large and modern egg producing and handling systems have made this a much more common occurence in modern times.

My recommendation for Mylissa20 is that the eggs be added later in the recipe, as previously suggested. It doesn't add anything to a preferment or sponge-there is no reason for egg to be included. It was probably just a convenient thing to add it to this step in the recipe.

Have safe and delicious fun.

clazar123,Public Health Nurse :)



G-man's picture

I know that salmonella from handling infected foods of any kind is a problem. I've worked in and around the food service industry in many capacities for nearly half my life. I work in health care at the moment but that's just until I can get back into food. Either way I do have plenty of perspective on this, both as a professional in the industry and in my own home.


Please don't disparage what you call 'heritage' recipes. The vast majority of those recipes are perfectly healthy to consume. If you've eaten meringue, mayonnaise, hollandaise, bearnaise, caesar salad, ice cream, tiramisu, or traditional pannetone, to name but a few, you've eaten raw egg products. All of those are what you might call "heritage" recipes, except perhaps the caesar dressing. Do you suggest we buy these things pre-fabricated by workers who don't know or care who is eating them? Do you suggest we not consume them at all because of the risk? If so, there's a problem with that idea.

What you're talking about is cross-contamination and can happen not just with raw eggs but with raw anything, including vegetables grown using untreated animal manure. This is The Single Greatest Lesson someone who handles food needs to learn.  There is truly no way at all to avoid cross-contamination...except washing your hands and other equipment, a trick that has served food service workers since the dawn of soap.


All I'm saying is that if you're careful you can eat a whole lot more than the manufacturers of processed food would like you to believe.

Mylissa20's picture

I commented to someone else above that the preferment pretty much contains everything in the recipe, so adding the eggs later might be hard.  Do you have a good suggestion for kneading in eggs without it turning into a goopy mess?

G-man's picture

If you're steadfast against using them at the stage the recipe calls for, adding them when you mix the final dough ingredients into the preferment should work just fine. Kneading eggs into an otherwise finished dough would probably be an exercise in futility.

pmccool's picture

when one moves.  Especially if the move is to another country.

Here in South Africa, eggs are not refrigerated in transit or in the supermarkets.  And it is not uncommon to see feathers or other (fecal) material still clinging to the shells.  We choose to keep the eggs in the refrigerator once we get home from the store, but that's the first time they have ever seen temperatures that low.

The only two cases of food poisoning that my wife or I have suffered in the past (counts fingers and toes) 16 months that we have lived here have come from a couple of mid- to high-end restaurants.  Now, I'm not advocating unrefrigerated storage of eggs or other perishable foodstuffs.  Nor am I likely to purchase unpasteurised milk from a dairy near here in spite of its certification.  Salmonella and other food-borne illnesses are no fun.  

Like the OP, I wouldn't let opened uncooked eggs sit for an extended period since they provide such rich medium in which bacteria can grow.  Still, many of our food fears are greater than the actual risks involved.  As shown by observable evidence, South Africans aren't experiencing a widespread public health problem associated with the handling and consumption of eggs.  What would be interesting is to have someone who keeps such statistics perform a comparison of the U.S.A. and R.S.A incidence rate of illnesses stemming from eggs.  Without such evidence, I can't be sure that the USDA's approach produces markedly better outcomes.  Maybe, as clazar123 points out, the real differences lie in the production methods employed.






Jaydot's picture

Just for the record: I've never refridgerated an egg in my life (I don't refridgerate cheese or butter either, unless it's a really warm summer), and I often let the dough/batter for quiche or cookies sit at room temp for an hour or two, raw eggs an' all.

So I completely agree that many food fears are greater than the risks involved...

My daughter did have a Salmonella infection once (nope, no fun at all), when she was about a year old. She was staying with her gran at the time. Poor gran was mortified, and she left no stone unturned in trying to find out what caused it. You can never be completely sure, but the most likely culprit was a vegetable. 

cranbo's picture

from what i've read from the USDA and other web sites, the biggest risk is temperature fluctuations:

Temperature fluctuation is critical to safety. With the concern about Salmonella, eggs gathered from laying hens should be refrigerated as soon as possible. After eggs are refrigerated, they need to stay that way. A cold egg left out at room temperature can sweat, facilitating the growth of bacteria. 

Granted that USDA is clearly advocating for refrigeration, whether truly required or not. I imagine you're right, some of this is simply done to maintain a government food standard. I wouldn't be surprised if that standard favors giant egg farmers who must store and transport eggs over long distances. 

The moral of the story is:

1. If you buy your whole eggs refrigerated, you probably should keep them refrigerated. This way they can last 3 weeks or more (some say up to 8 weeks even). You can safely leave your refrigerated eggs at room temp for 2 hours, more and you may be increasing your risk. 

2. If you buy your whole eggs unrefrigerated, you probably can keep them at room temp safely. How long will they last? Probably 1 week, possibly a little more, from what I've read. Don't wash your eggs! They will last longer. 

3. If you crack an egg and it smells like "rotten egg" (sulfur), refrigerated or not it's certainly spoiled. 

4. A cracked, scrambled egg at room temperature will likely spoil at the same rate as fresh meat.

Ford's picture


In research done by the M. G. Waldbaum Company in collaboration with the University of Georgia, University of Missouri, and North Carolina State University, scientists have demonstrated that whole eggs heated for six minutes at 133 degrees F in a sterile water environment eradicated the Salmonella enteritidis (Se) bacteria that was inside the eggs.  James Schuman of the M. G. Album Company reported the results in February 2000 at the Watt Poultry's Summit III on Food-borne Pathogens in Poultry, held in Atlanta, Georgia.  (Summarized from Food Chemical News, March 20, 2000, p. 4.

Author: Marc Doussard.  (See also eFOOD RAP, 10, Number 17, September 1, 2000, William D. Evers, PhD, RD, Cooperative Extension Foods and Nutrition Specialist, Purdue University School of Consumer and Family Sciences Department of Foods and Nutrition)

I place the eggs in a saucepan and cover them with an inch of warm water, heat the water to a temperature between 135°F and 140°F, and hold it in that temperature range for ten minutes.  I then pour off the hot water, run cold water over the eggs, and then add ice to chill them.  The egg whites may become slightly cloudy, but they are not cooked.


As for scalding buttermilk, I scald 1% butterfat milk, cool it to about 100°F, add that to about half as much fresh, cultured buttermilk, and let this ferment for 12+ hours at room temperature.  This does not deactivate all the protease in the buttermilk, but after five repeats of this process only 4% of the original amount of protease in the buttermilk remains.

osx-addict's picture

We have 4 hens that lay eggs and we keep all of them on the counter in the kitchen -- they're never refrigerated.. They are also unwashed until we choose to use them or give them to friends/neighbors.  We've kept them for weeks like this in some cases with no ill effects.  Unwashed eggs from laying hens have something called "bloom" on them that works as an anti-bacterial and as long as no washing has been done, that bloom does its job to keep bad stuff out.  You can read more about egg storage here (from a few years back) :

Ruralidle's picture

We also keep hens and we have never refridgerated their eggs unless we accidently crack one.  Indeed, supermarkets and farm shops in the UK rarely keep their eggs in cold cabinets and since the Edwina "Eggwina" Curry (former UK politician) scared everybody over salmonella in eggs there have been no major problems.  Use eggs within 4 weeks of production and everything seems OK - I even make my own mayonnaise with our fresh, raw, eggs and have done so since we first had hens, with no problems at all.

Perhaps refridgerating eggs is health and safety taken to extreme (gone mad)!!??

Mylissa20's picture

Ok, so if the salmonella danger is exactly the same for this dough as it would be for chocolate chip cookies, then maybe the question to ask is whether or not an unrefrigerated soak could possibly result in spoiled eggs, and some kind of food poisoning.  for some reason in my mind I was lumping salmonella together with food poisoning and I'm realizing that I was talking about two different things.  what is the possibility of people getting sick from raw eggs in a total of 10-12 hours of unrefrigerated soaks and rises?

SallyBR's picture

I am not sure I understand your question - unrefrigerated soak, means ssoaking the eggs in water at room temperature?   Why would that contaminate the egg????


A contaminated egg is present at an average of 1 in 10,000 eggs - if the egg is not contaminated with Salmonella to start with, no soak in water will make it be contaminated, unless your water is filthy!  ;-)


I think it's important to distinguish between "harmless bacteria"  and pathogenic bacteria - harmless, non-pathogenic bacteria are present everywhere and cause no problems.

Mylissa20's picture

Ok, so what I meant to say is that for the recipe, you mix your final dough using the levain, eggs, etc.  Then the final dough proofs (or soaks, as some people say) for 12 hours.  You then shape your bread, give it a final 2 hour proof, and bake.  So if the salmonella danger is comprable to that of cookie dough, is there a danger of the eggs spoiling in the dough during the proofs?  Is that worded better?  sorry I'm not always good at spitting out what's in my brain.

G-man's picture

The chances of an egg spoiling in that small a period of time are very, very low. The good thing is that if you have ANY doubt, it can be dispelled (or confirmed, god forbid) by doing a simple test: Lean over the bowl and get a nice, large whiff. The smell of rotten eggs is immediately recognizable unless you just stuck your face in some sulfur, in which case you have larger problems than food spoilage. If they don't smell like rotten eggs, they're not rotten.


Eggs are probably one of the most awesome foods ever.

cranbo's picture

Hi Mylissa20,

Yes, I would say the spoilage danger is comparable to cookie dough or any other fresh animal product that has already been incorporated into a recipe.