# Why isn't mayonnaise refrigerated before it's opened? **URL:** \ **Category:** Factual Questions\ **Created:** [May 23, 2006, 7:20am UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876 "2006-05-23T07:20:23Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 23, 2006, 9:39pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/21 "2006-05-23T21:39:57Z")
[QUOTE=Alan Smithee] (Actually, I’ve read on the boards that eggs can be kept out of the fridge, too!) [/QUOTE] Well, the chickens do! Back on the farm, we never had any refrigration running into the nests. In fact, I think the hens would have objected to having to sit on such a nest! ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 23, 2006, 9:42pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/22 "2006-05-23T21:42:57Z")
[QUOTE=Alan Smithee] (Actually, I’ve read on the boards that eggs can be kept out of the fridge, too!) [/QUOTE] Well, the chickens do! Back on the farm, we never had any refrigration running into the nests. In fact, I think the hens would have objected to having to sit on such a nest! And we often took eggs fresh from the nest into the kitchen for use. (Definately a noticably better taste when they are that fresh.) ---
**Author:** ![Sierra\_Indigo](https://avatars.discourse-cdn.com/v4/letter/s/f0a364/32.png) [@Sierra\_Indigo](https://boards.straightdope.com/u/Sierra_Indigo)\ **Post date:** [May 23, 2006, 11:15pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/23 "2006-05-23T23:15:33Z")
Hubby from the UK was quite surprised when I (in Australia) put eggs in the fridge the first time we got some. Eggs can be kept out of the fridge, I just prefer to keep mine in the fridge because a) It’s got an egg holder and b) it does get terribly hot over here, where it doesn’t in some other parts of the world, and I’d rather not have my eggs semi-scrambled by being left in a 40+degree kitchen for most of the day. Mayo I will keep in the fridge specifically because of spoilage, however. I’ve left a jar of mayo out one summer day, and the result was nasty. ---
**Author:** ![Monty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/monty/32/47_2.png) [@Monty](https://boards.straightdope.com/u/Monty)\ **Post date:** [May 23, 2006, 11:30pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/24 "2006-05-23T23:30:27Z")
[QUOTE=Alan Smithee] (Actually, I’ve read on the boards that eggs can be kept out of the fridge, too!) [/QUOTE] That’s pretty much the standard way of storing eggs in this part of the world. Even when I forego buying eggs on the base and get them at the local store, I still put them in my fridge at home. I guess I just can’t get over the way I’m used to seeing it done (stored in the fridge). ---
**Author:** ![rainy](https://avatars.discourse-cdn.com/v4/letter/r/c2a13f/32.png) [@rainy](https://boards.straightdope.com/u/rainy)\ **Post date:** [May 24, 2006, 12:09am UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/25 "2006-05-24T00:09:36Z")
Growing up on a small farm where we had fresh eggs, I was always told that eggs were fine left out on the counter UNTIL you put them in the fridge, then they had to be stored that way to avoid spoilage. Truth or wives’ tale? -rainy ---
**Author:** ![solkoe](https://avatars.discourse-cdn.com/v4/letter/s/919ad9/32.png) [@solkoe](https://boards.straightdope.com/u/solkoe)\ **Post date:** [May 24, 2006, 12:36am UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/26 "2006-05-24T00:36:56Z")
Back to the mayo question, how many responders who think mayo can be kept out of the fridge actually keep it out of the fridge? My wife has worked as a waitress and says that mayo is a big concern for chefs. If it is left out, even for a few hours, it is discarded. To me, that is a strong hint that it should be kept refridgerated. ---
**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:** [May 26, 2006, 1:37pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/27 "2006-05-26T13:37:41Z")
[QUOTE=solkoe] Back to the mayo question, how many responders who think mayo can be kept out of the fridge actually keep it out of the fridge? My wife has worked as a waitress and says that mayo is a big concern for chefs. If it is left out, even for a few hours, it is discarded. To me, that is a strong hint that it should be kept refridgerated. [/QUOTE] Your wife’s chefs are wrong. They toss the mayo (that sounds kinda dirty) because they are afraid of litigation, not because it’s unhealthy. Even if the mayo were contaminated, it would take far longer than a couple of hours for the bacteria to multiply to a level where they would become a health risk. The; warm mayo=dangerous comes from a time when mayo was made with fresh eggs, and potato salad was left out for days. But warm mayo does indeed=yuck. ---
**Author:** ![Beware\_of\_Doug](https://avatars.discourse-cdn.com/v4/letter/b/278dde/32.png) [@Beware\_of\_Doug](https://boards.straightdope.com/u/Beware_of_Doug)\ **Post date:** [May 26, 2006, 3:59pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/28 "2006-05-26T15:59:17Z")
A bad-mayo anecdote involving TV studio lighting turns up in _Please Stand By_, a fun but very sloppily written book by film director Michael Ritchie about the earliest days of programming. Tex and Jinx, a couple with a popular daytime radio show, took to the tube in 1947 for Swift Meats. The commercials involved making lunches of canned corned beef, vienna sausage, etc. Trouble was, Tex couldn’t stand the stuff without gobs of mayo…and the meals had to be made up before airtime…_and_ TV lights in 1947 were roasting hot. So Tex’ mayo always spoiled before he had the chance to eat it. Rather than lose the sponsor, the guy actually had a bucket placed right off camera, where he, uh, divested himself of the noon meal as soon as practicable. Luckily, they only did the show once a week, and it only lasted a season. But man! What a trouper. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [May 26, 2006, 5:11pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/29 "2006-05-26T17:11:53Z")
FTR, my degree is in microbiology. So. The concern with mayonnaise is of course salmonella infection. A small but not insignificant percentage of eggs out there are infected with the bacteria, and seeing as how large commercial plants will make huge vats of the stuff with lots and lots of eggs mixed together, it pays to be careful. How careful? Well, pure mayo cannot support bacterial growth. Its water activity is too low - all the water is in emulsion, so it’s not biologically available. The bacteria won’t die, but they won’t be able to reproduce to dangerous levels. So as long as you’re dealing with pure mayo, refrigeration is not needed. But once you’ve opened the jar and stuck your bread crumb-coated knife in, you’ve potentially added something the bacteria can use to grow. Essentially, you’ve given the bacteria a food and water source. So if there’s a chance that something foreign has been mixed into your mayo, stick it in the fridge. I think there’s also oxidation and rancidity to consider, but that’s beyond my range of knowledge. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [May 26, 2006, 8:02pm UTC](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876/30 "2006-05-26T20:02:43Z")
[QUOTE=solkoe] Back to the mayo question, how many responders who think mayo can be kept out of the fridge actually keep it out of the fridge? . [/QUOTE] I do. Well, most of the time the mayo jar stays in the fridge because it’s convenient. But sometimes, I put it in a cupboard instead. Plus, since I don’t clean up afer every meal, the mayo often stays on the table until the following day. Actually, there’s precisely a jar of mayo on the bar since yesterday when I ate some. So, my mayo tends to spend a lot of time opened and outside the fridge, and never turned bad. The only mayo that goes systematically in the fridge is the mayo I make myself, because left outside, it tends not to keep its consistency and to devolve into its original components. [Previous page](https://boards.straightdope.com/t/why-isnt-mayonnaise-refrigerated-before-its-opened/357876.md?page=1)