# Mayonnaise does NOT need to be refrigerated, dammit! **URL:** \ **Category:** Factual Questions\ **Created:** [July 22, 2001, 10:24am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431 "2001-07-22T10:24:53Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [July 22, 2001, 10:24am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/1 "2001-07-22T10:24:53Z")
I have argued this with people for years. The label merely says **TO KEEP FRESH, REFRIGERATE AFTER OPENING.** It would say **MUST BE REFRIGERATED** if that were the case. And there is nothing in mayonnaise that would require refrigeration. It’s basically just vegetable oil. I think that it’s only because it’s white that people insist on refrigerating it. They associate it with milk or cream. ---
**Author:** ![Mikahw](https://avatars.discourse-cdn.com/v4/letter/m/e9bcb4/32.png) [@Mikahw](https://boards.straightdope.com/u/Mikahw)\ **Post date:** [July 22, 2001, 10:35am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/2 "2001-07-22T10:35:08Z")
I know there’s a question in here somewhere. I just can’t seem to find it. Oh well… ---
**Author:** ![Dijon\_Warlock](https://avatars.discourse-cdn.com/v4/letter/d/a9a28c/32.png) [@Dijon\_Warlock](https://boards.straightdope.com/u/Dijon_Warlock)\ **Post date:** [July 22, 2001, 10:39am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/3 "2001-07-22T10:39:39Z")
> [@](#): > > \*Originally posted by Mikahw \* > \*\*I know there’s a question in here somewhere. I just can’t seem to find it. Oh well… \*\* How’s about “Why was this posted in GQ?” ---
**Author:** ![The\_Fromesiter](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@The\_Fromesiter](https://boards.straightdope.com/u/The_Fromesiter)\ **Post date:** [July 22, 2001, 10:39am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/4 "2001-07-22T10:39:51Z")
I think it’s more about the fact that no one wants mayonnaise that isn’t fresh. I mean, yea, that fish may be a few days old, but it’s still edible. So what if it’s not fresh, you can still eat it, it just smells kinda fishy. ---
**Author:** ![Chas.E](https://avatars.discourse-cdn.com/v4/letter/c/e99b99/32.png) [@Chas.E](https://boards.straightdope.com/u/Chas.E)\ **Post date:** [July 22, 2001, 10:43am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/5 "2001-07-22T10:43:54Z")
> [@](#): > > \*Originally posted by Hail Ants \* > **I have argued this with people for years. The label merely says TO KEEP FRESH, REFRIGERATE AFTER OPENING. It would say MUST BE REFRIGERATED if that were the case. And there is nothing in mayonnaise that would require refrigeration. It’s basically just vegetable oil.** And raw eggs. Mayonnaise is oil plus RAW EGGS. Go ahead and leave raw egg products out of the refrigerator, but don’t ask me to eat it afterwards. You can’t even leave potato salad made with mayo out in the sun at a picnic for an hour without refrigeration or everyone will get sick from salmonella. Leave your mayo in the fridge and your rants in IMHO or MPSIMS. ---
**Author:** ![FarmerOak](https://avatars.discourse-cdn.com/v4/letter/f/e9c0ed/32.png) [@FarmerOak](https://boards.straightdope.com/u/FarmerOak)\ **Post date:** [July 22, 2001, 11:15am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/6 "2001-07-22T11:15:04Z")
I don’t have the link yet (FLAME RETARDANT) but I did read a good article last year in the food section of my local paper. Apparently, **Hail Ants** has a point. Something about the acidity of mayo makes it OK to NOT refrigerate. I have a numer of (unopened) jars of of mayo in my pantry which are well past the BEST IF USED BY date. Apparently, that date is used strictly to move inventory, and has no bearing on quality of product. I have used these jars and the mayo is tasty, and the Farmer is not yet dead. That having been said, I refrigerate EVERYTHING after opening, including mayonnaise, mustard, ketchup, pickles (also unnecessary) and potato chips (unnecessary and unwise.) And I couldn’t find a question in that rant either. **Hail Ants** , I got three bucks that says this is not the ONLY thing you have been arguing about for years. I’ll catch up when this gets moved to IMHO. ---
**Author:** ![Tedster](https://avatars.discourse-cdn.com/v4/letter/t/4491bb/32.png) [@Tedster](https://boards.straightdope.com/u/Tedster)\ **Post date:** [July 22, 2001, 3:22pm UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/7 "2001-07-22T15:22:04Z")
Interesting. A few months ago, that warning was _not_ found on the Hellman’s Mayonnaise label. I know because I checked. I guess the Straight Dope brought the Mayo people to their senses. But you’re correct, it tastes nasty if not refrigerated. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [July 22, 2001, 3:48pm UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/8 "2001-07-22T15:48:20Z")
> [@](#): > > … But you’re correct, it tastes nasty if not refrigerated. Further evidence that it’s the same whether refrigerated or not - leaving it out doesn’t make it stop tasting nasty. Oh, wait, we had our condiment wars thread a while back in that thing on the zen of the pastrami sandwich. > [@](#): > > That having been said, I refrigerate EVERYTHING after opening, including mayonnaise, mustard, ketchup, pickles (also unnecessary) and potato chips (unnecessary and unwise.) POTATO CHIPS!!! It’s strange, and I can’t imagine wanting to eat a nice cold potato chip, but given that you leave them wrapped up so moisture doesn’t get in, why is it unwise? Condensation? Pickles I’ve been known to leave out overnight because I’ll sometimes eat them or green olives in bed. I suppose there’s Freudian implications in that, but, actually, I just like pickles. And I like to suck the pimentos out of the green olives before I eat them. So there. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [July 22, 2001, 4:10pm UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/9 "2001-07-22T16:10:26Z")
> [@](#): > > _Originally posted by Attrayant, in the last thread we had on this subject_: > > According to [The Food Marketing Institute](http://www.fmi.org/consumer/foodkeeper/brochure.htm): > > > [@](#): > > > > Refrigerate after opening. > > The [Center for Food Safety and Quality Enhancement](http://www.griffin.peachnet.edu/cfsqe/Pages/Mayo.html) says that regular mayo has enough vinegar in it to stall salmonella groth and may help preserve other foods when mixed in (like chicken salad), but they also say: > > > [@](#): > > > > Mayonaise will not maintain its acidity level very well over time when mixed with other less acid foods like meats, poultry, eggs or potatoes," she said. "Bacteria can begin to multiply if these foods are allowed to remain between 40 and 140 degrees F. Always keep salads such as these at refrigerator temperature. > > > > For safety and the best quality, Harrison said, refrigerate the mayonnaise, too. > > > > The more times you open the jar and remove some of the product, the more chances there are for moisture, food particles or mold spores to enter the mayonaise. This could cause changes in the mayonnaise itself, **especially at room temperature**. > > > > Using a clean knife or spoon each time, she said, will make food particles less likely to get into the jar. > > Clearly, cross-contamination is a concern. The implication is that with regular useage, just double-dipping a knife into the mayo jar may be enough to introduce some contaminant that may encourage the mayo to spoil. Sure, if your kitchen is so clean that you can make microchips in it then your mayo is probably safe. But most kitchens are teaming with cooties and the mayo jar is a virtual petri dish. ---
**Author:** ![FarmerOak](https://avatars.discourse-cdn.com/v4/letter/f/e9c0ed/32.png) [@FarmerOak](https://boards.straightdope.com/u/FarmerOak)\ **Post date:** [July 22, 2001, 7:53pm UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/10 "2001-07-22T19:53:28Z")
Thanks for the link, **Attrayant**. Glad to know I didn’t make that up in my own head. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [July 22, 2001, 7:56pm UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/11 "2001-07-22T19:56:15Z")
Oops. Mods please move to GD or MPSIMS (so sue me.) I **do** refrigerate my mayo at home. It’s just that most people seem to insist that you will literally drop dead from eating it unrefrigerated. Ketchup is made of tomatos which obviously go bad if not refrigerated but no one minds using the bottles that sit out on restaurant counters all the time. My GQ should have been does anyone have any proof that it does need to be kept cold (which most of you figured out). ---
**Author:** ![light\_strand](https://avatars.discourse-cdn.com/v4/letter/l/a6a055/32.png) [@light\_strand](https://boards.straightdope.com/u/light_strand)\ **Post date:** [July 22, 2001, 9:13pm UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/12 "2001-07-22T21:13:57Z")
Since you’ve finally asked a GQ I’ll take a shot > [@](#): > > And raw eggs. Mayonnaise is oil plus RAW EGGS Commercially prepared mayonnaise does not contain raw eggs. It contains pasteurized eggs. That said, I wouldn’t eat mayonnaise that hasn’t been refrigerated either. Besides being extremely yucky, it is risky due to cross-contamination as mentioned by **Attrayant**. Now if you make your own mayo, you absolutely **must** store it refrigerated as you cannot be sure that your oil and/or eggs are not contaminated. Further info: > [@](#): > > You can’t even leave potato salad made with mayo out in the sun at a picnic for an hour without refrigeration or everyone will get sick from salmonella _Salmonella_ spp. has a doubling time of roughly 20 minutes. This means that if you had one organism in your mayo, and left it out in ideal conditions, in an hour you would have a sum total of eight organisms. Of course you’d probably have more than one organism to start out with, but even if you have, let’s say, 100 CFU of bacteria, in an hour you’d still only have 800 CFU. Your immune system should easily be able to handle that. I don’t think these numbers are enough to lose sleep (or your lunch) over. Of course since this is a logarithmic progression, I wouldn’t eat if it’s been left out over night. As for Ketchup, it is highly acidic since the number one ingredient is vinegar. Mold would be a much bigger problem than bacteria in ketchup. However, because of the way that ketchup is packaged (in the squirt bottle) you are much less likely to contaminate ketchup than you are mayo. I personally don’t like cold ketchup, so I leave it out at room temp. But a good rule of thumb for food is: If it smells funny, don’t eat it. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 23, 2001, 12:18am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/13 "2001-07-23T00:18:48Z")
> [@](#): > > Salmonella spp. has a doubling time of roughly 20 minutes. using that 1 will multiply to 134,217,728 over an 8 hr night (not sure if I got exactly the right number but it’s pretty large. That said doubling 1/20 minutes is under ideal conditions - the time can be much longer. ---
**Author:** ![JillGat](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@JillGat](https://boards.straightdope.com/u/JillGat)\ **Post date:** [July 23, 2001, 12:19am UTC](https://boards.straightdope.com/t/mayonnaise-does-not-need-to-be-refrigerated-dammit/73431/14 "2001-07-23T00:19:35Z")
This does not appear to be a question, so I will close this one and refer readers to this thread [Does soy sauce need to be refrigerated?](http://boards.straightdope.com/sdmb/showthread.php?threadid=78928) which also discusses this (and related) issues.