Could I Eat It: Self repackaging Mayonnaise without Refrigeration

July 18, 2022 4:39 PM

Can I repackage store-bought mayonnaise into small portions and eat it a few days later, unrefrigerated, without dying?

I'm going backpacking for 4 days and I enjoy trail burritos (tortilla, packet of tunafish, cheese, mayo, mustard and perhaps some radishes and Fritos).

I already know how to get single-serving mayo packets (buy them online, get them from a gas station or fast food shop, etc.). Please don't answer that question.

If you google the question about whether mayo needs refridgeration, within the top 5 results are answer such as "Yes, if it sits for more then 8 hours at 50F, you must throw it out" as well as "Actually, commecrial mayo has enough acidity that it keeps for days or weeks"

Many people think "mayo = eggs" when in fact "mayo = oil" (mostly) and oils often do not spoil quickly. I'm inclined to believe the people saying "it's pretty safe" but I'm open to opinions.

My idea is to take a fresh jar of commercial mayo, dole out some servings into ziploc bags or nalgenes, freeze them until the trip, and then carry them and eat them over the next 4 days. Temperatures would be about 40F at night and perhaps 80F during the day.

posted by soylent00FF00 to Food & Drink (18 answers total)

Absolutely not.
posted by Champagne Supernova at 4:47 PM on July 18, 2022

On one hand, if you actually read the news that says commercial mayo is acidic and try to go back to actual research, you ultimately dead end with an unsourced claim from anonymous 'food scientists' quoted in a PR report by a data analytics firm trying to sell subscriptions to a packaging tracking study. Even that weak source never suggests that random re-packaging of food from sterile, self-sealing condiment bottles into ziploc bags couldn't possibly contaminate it. And it certainly says nothing about the wisdom of doing all this in a situation when one has highly limited access to food, drink or medical help if things do go wrong digestive-wise.

On the other hand, I'm sure bears are long tired of being the only target of cliches about shitting a lot in the woods, so you would be doing them a favour.
posted by Superilla at 4:52 PM on July 18, 2022

No. Buy those pre-mixed tuna salad packets, they're pretty good.
posted by ananci at 4:55 PM on July 18, 2022

In this situation I might consider a half-full container of Kewpie mayo. The way it squeezes out of a small opening, without letting any air back in, due to the flexible tubelike plastic, might suit your purpose quite well.

Intestinal fortitude varies greatly, so this would work just fine for my partner, but not myself.
posted by dum spiro spero at 5:13 PM on July 18, 2022

You can't freeze mayonnaise, the emulsion will break. Then you'll just have oil. Which I highly recommend, oil is shelf stable and while the texture is a little different from mayo, mixed up in the way you describe it makes an excellent addition. I even have a backpacking book from the 80s that recommends bringing a bottle of oil and just drinking it.

I get the temptation, I do bring cheese for the first few days and it's fine. Ketchup and mustard are fine, too. It's true, the water content in commercial mayo is basically zero, there is acidity, and the potato salads in the sun thing is because of the potatoes. Human pH is near neutral, so bugs that are bad for us grow in neutral environments, as a rule.

So, I would not do this, but if I just had to repackage shelf-stable mayo I would definitely whisk in an extra tablespoon or two of vinegar into the jar of mayo. I might also look at Mexican and Central American markets, their portions and packaging tend to be much more backpacker friendly.
posted by wnissen at 5:22 PM on July 18, 2022

I think you're referring to this study: https://pubmed.ncbi.nlm.nih.gov/10945595/
Every source I could find, especially this one, says that mayonnaise is very safe.
There's this mystique about it: if you let light touch it it mysteriously becomes poisonous due to an overgrowth of escherischia coli, a bacteria you already have in your guts.
I know of no food like this. You have to be stupidly careless with food to have it become unsafe, and when you do it won't be the mayo that gets you.
If you freeze it it's not going to grow bacteria - e. coli does not to the best of my knowledge thrive when frozen. I suspect that if you put it in a clean, new ziploc bag with a clean spoon, it's highly unlikely that there'll be any bacteria in there to grow.
I would do this without a second thought.
posted by AugustusCrunch at 5:23 PM on July 18, 2022

FWIW, I use the mayo that's in the squeeze bottle that you leave upside down.... it sits out on the counter and has for years (different bottles of course). It can get to 80+ in the apartment. The mayo has never seen the inside of a refrigerator. It has been fine. YMMV.
posted by zengargoyle at 5:43 PM on July 18, 2022

The risk of being ill while camping would make me say No.
posted by theora55 at 6:24 PM on July 18, 2022

So... the thing that would give me pause is the backpacking part of this. If you're even a few miles away from the trailhead you parked at, and likely even more miles from the nearest hospital, that won't be the time to discover that hey, in fact mayo can give you food poisoning (or not, but that's not the interesting case). I don't think I'd have that kind of risk tolerance myself and would go with the shelf-stable packets instead of trying to DIY this.
posted by Aleyn at 6:25 PM on July 18, 2022

I'm no mayonnaisologist but when I was a Peace Corps volunteer in West Africa, I would sometimes buy mayo and bring it back home where it would sit for a week or more as I used it, with no refrigeration, sometimes on days where the lows at night were in the upper 80s. I was fine. But I was also taking daily doxycycline as an anti-malarial, and that's also an antibiotic, which is potentially important context for that anecdote.
posted by solotoro at 6:46 PM on July 18, 2022

foodsafety.gov specifically lists opened mayonnaise as one of the things you should "discard (if above 50 °F for more than 8 hrs)". Personally, I wouldn't risk it...but if I were going to, I would experiment at home first, not during a backpacking trip.
posted by hooray at 7:37 PM on July 18, 2022

Anecdata, but a family friend kept using an open jar of mayo that had been on a day+ warm car ride, saying "enh, it'll either make me sick or it won't". I was a bit appalled, and not even smug when he got food poisoning, because yeesh. So, clearly there are alternate anecdata above, but I would absolutely hate having food poisoning in the woods, and would not do this.
posted by ldthomps at 7:26 AM on July 19, 2022

I've marked some of the more extreme answers on both sides as 'best' though I think all the answers are great. It's interesting that there seems to be so little consensus on this!
posted by soylent00FF00 at 8:32 AM on July 19, 2022

Grabbing a bunch of mayo packets from Quiznos seems cheaper, more convenient, and safer than portioning out a fresh jar of Hellman's so I can only assume it's a flavor/texture issue. Might want to do a taste test on a defrosted baggie of mayonnaise that's been sitting in a Nalgene for three days of 80° heat before committing to play dookie roulette in the woods
posted by katiec at 8:55 AM on July 19, 2022

A vote against.

In these situations, I ask myself, what factors would my epidemiologist dad consider. Holding temp, temperature swings, initial cleanliness of containers, introduction of contaminants in packaging process, etc. Too much to get right, even with the allegedly-wide margin of error you get by starting with a commercial product.

If I asked him this question - and I've asked him similar over the years - I'm 100% certain he would say, don't reject a known safe product or procedure and replace it with something with many variables. Plus, he would share anecdotes of what food poisoning is like, just for fun.
posted by Caxton1476 at 9:20 AM on July 19, 2022

I suspect it also depends heavily on the ingredient proportions for mayo. I know that the typical "mayo" has a pretty wide variation from region to region and I especially wouldn't trust that mayo from other countries would behave the same way that domestically-produced mayo would, or even possibly brand-to-brand.
posted by Aleyn at 1:53 PM on July 19, 2022

I returned from the trip. I did not die or get sick. Some of you will be dissapointed to know that I chickened out - rather than repackaging my own mayo, I found some mayo packets that I believe were purchased in 2019. So at least 3 years old, possibly older. They tasted fine.

I was shocked to discover that most condiment packages have NO MANUFACUTRE OR EXPIRATION DATES and I'm not sure how that factors into this discussion.
posted by soylent00FF00 at 2:54 PM on July 26, 2022

If you're looking for something that is just oils, you might try vegan mayo. Though the packaging still recommends refrigeration, I don't know if it's necessary. (For future trips.)
posted by blueberry monster at 11:04 AM on July 31, 2022