Sterilizing Mayonnaise?

As I posted in the past, I have this really nice, really old recipe for mayonnaise from my grandmother. I tried in vain to find the thread that I posted on this message board. No matter, I do still have the recipe in my computer files: *GRANDMA’S MAYONNAISE DRESSING:

½ t. Mustard, 1 Tb. Sugar, ½ t. Salt, 3 Tb. Vinegar, ⅛ t. Paprika, 1½ C. Salad Oil, 1 Egg.

** Mix the dry ingredients thoroughly. Add the well-beaten Egg and Acid. Add the Oil, a fourth of a cup at a time, beating constantly. More Acid may be used, by adding it at the Root–???*

Anyways, as I said in the old thread, I’d love to make this recipe. But I fear raw eggs. They sometimes contain Salmonella.

Anyways, commercial Mayonnaises like Hellmann’s sterilize their Mayonnaise as they can them. And they don’t seem to have to alter the recipe to do this. Here is Hellmann’s ingredients, if you’re interested. Notice, no separate thickeners like cornstarch seem to be added.

So my question is, can I simply make this recipe for Mayonnaise, and then sterilize it afterwards? I don’t have a cite. But I’ve never heard of anyone ever doing that. Is there a reason why? Also, you have to admit (again, no cite) that Hellmann’s Mayonnaise is much thicker than homemade. Homemade Mayonnaise tends to be looser, I’ve noticed. Chime in with your own experiences, to support my claim. Or conversely prove me wrong, if you want :slight_smile: .

Again, my question is simply can you heat and sterilize homemade Mayonnaise? Because I’ve never heard of that even once. Once more, your own experiences would be helpful.


The mayonnaise isn’t sterilized, the eggs are pasteurised before making the mayo.

You can do it yourself with a little of the vinegar from your recipe.

How to Pasteurize Eggs in the Microwave

We have hens. I use their eggs raw with impunity, in mayonnaise, aioli, smoothies, etc. In the winter when they stop laying, I’ll buy supermarket pasteurized eggs.

Also, consider modifying your recipe. Adding oil 1/4 cup at a time caught my eye. Making an emulsion I drizzle the oil very slowly, beating constantly.

If you have a sous vide you can pasteurize eggs there.

You might want to reconsider that. “it’s estimated that about 1 in 20,000 to 1 in 10,000” commercial eggs are infected with salmonella, and if salmonella is discovered the eggs get recalled. In other words, the odds aren’t great, but they are managed.

Your own chickens, on the other hand, you have no idea if they are infected with Salmonella “even when they appear healthy and clean”. I understand feeling that, “These are my chickens, I keep them clean and healthy, so the eggs must be safe” but that’s not how it works.

We eat a few raw each week during summer. Drop a raw egg into a smoothie and whip it good. The texture is amazing.

You only need the yolk, and that can be pasteurized.

Or use a stick blender. Two-Minute Mayonnaise Recipe

I bet you mean this one:

Follow up question, if I may…

So, as you all know, mayo comes unrefrigerated. But not refrigerating it once you open the jar is basically a death sentence. But why?

Is there any reason why you can’t buy a large jar of Hellman’s, using a very clean spoon transfer some to a smaller container to refrigerate for frequent use, and store the original remaining mayo at room temp for use later?

What got into the mayo from the open air while the lid was off? Maybe nothing. Maybe something.

Modern aseptic packaging is all about zero, not nearly zero, living organisms in your shelf-stable food.

So how does that work exactly? How do they keep the air under the lid from contaminating the food while it sits on the shelf?

What are you going to do after opening the mayo jar? Stick a knife in it, right? The act of sticking a knife into the mayo increases the surface area through which microbial action can occur. Then you use the knife to spread mayo on bread. Then you stick the knife back into the mayo so you can spread more mayo on your bread. So now you’ve transferred possible microbes from the bread into your mayo, not to mention any crumbs of bread that stuck to the knife giving the microbes even more avenues of transfer. Plus the knife does a good job of mixing up the mayo, the crumbs, and the microbes. Perfect microbial growth medium.

No, not quite the scenario I described.

I was just wondering why mayo would become not shelf stable if you removed part of the contents with a very clean utensil… say a spoon cleaned with boiling hot water or cleaned with rubbing alcohol.

Commercial mayo doesn’t need refrigeration after opening if you don’t contaminate it with food. Until not long ago, the jars all said something like “best if refrigerated after opening” but it wasn’t necessary.

Mayo does not need to be refrigerated after opening. It’s a good idea to help maintain the flavor and because people constantly contaminate mayo by putting a dirty utensil back in the jar where bits of other food can end up spoiling.

Once again, mayonnaise is a pile of oil with a small amount of egg dispersed through that oil in an emulsion. The egg is not exposed to the air and will not spoil. The oil will not spoil, and because of the emulsion will barely even oxidize over time.

People do not get sick from eating unrefrigerated mayonnaise. They get sick from eating potato salad or ham salad or some other middle American concoction left out in the hot sun for hours at a picnic.

Thanks, @needscoffee & @TriPolar.

I probably won’t tempt fate. Just one of those things I think about when the fridge is overtaken by little jars of things that my wife insists will kill us if we don’t refrigerate immediately after opening.

At the rate that I consume mayo, it won’t be the lack of refrigeration that kills me.

I don’t doubt it, but that wasn’t my point.

My family had chickens when I was growing up, and I was basically taught that our home-grown eggs were safe to eat raw while supermarket eggs were extremely risky. That is false. I still eat over-easy eggs and raw cookie dough, but I would now be uncomfortable doing that with homegrown eggs, because unless you’re testing your flock regularly you literally have no idea if there’s a salmonella outbreak in your flock.

There hasn’t been a salmonella outbreak in the US linked to commercial eggs since 2018 when 45 people got sick. Meanwhile, in 2020 over 1700 people were infected with salmonella from backyard poultry. Granted, that’s not necessarily via the eggs, but it would be really hard to tease out who got infected from handling the birds and who got infected from eating their eggs. The point is, your backyard chickens are far more likely to make you sick than commercial eggs.

I fully support keeping chickens, for sure. Just be aware of the risks and behave accordingly.

If it’s not mayo, and not something pickling in vinegar, then it is a very good idea to refrigerate it after opening. Since the ingredients vary so much from 100% pure industrial chemical content to all natural ingredients scraped from the processing machines after recognizable food has been packaged then you might as well assume they won’t last unrefrigerated.