# Salmonella, lunch boxes, and no refrigeration **URL:** \ **Category:** Factual Questions\ **Created:** [October 21, 2002, 6:15pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270 "2002-10-21T18:15:01Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 21, 2002, 6:15pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/1 "2002-10-21T18:15:01Z")
I just pulled my lunch box out of the fridge. (It’s really cool, BTW – a metal _The Evil Dead_ one with a thermos.) I put it in the fridge in the first place because my sandwich is balogna w/mayonaise and mustard. When I was a kid I had a lunch box very similar to the one I now use (except it had cowboys on it). I’d carry it to school, about a 20-minute walk, and place it in a cupboard in the classroom. The sandwich was the same kind I’m eating today. The cupboard was not refrigerated – just a cupboard. And yet kids weren’t keeling over from food poisoning. How long can you leave your balogna sandwich, with mayo, on a shelf without it “going bad”? ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [October 21, 2002, 6:36pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/2 "2002-10-21T18:36:36Z")
From the time you make it in the morning until lunchtime. 😉 Didja ever notice how several generations of American schoolkids managed to survive eating four-hours-old bologna-and-mayo sandwiches without dying of food poisoning? Just use common sense–put it in a reasonably cool, room temperature-ish place (like, NOT on the dashboard of a car in the sun, or NOT on the radiator at school), and don’t worry. ---
**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:** [October 21, 2002, 7:02pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/3 "2002-10-21T19:02:34Z")
Your sandwich should be fine. Most commercial mayo does not contain raw eggs any more. However, for the sake of argument, let’s say that you made your own mayo or managed to contaminate the jar with a bacteria infested knife. Assuming that you store your mayo in the fridge, the bacteria should not start doubling until your sandwich gets to room temp. Now the doubling time for _Salmonella typhi_ is ~30 min. So if you started out with 10 bacteria in your sandwich, then in 30 minutes you’d have 20, in an hour you 40, etc. So you’d probably have to leave your sandwich out at room temp for about a day, or a day and a half before you have and ill effects. However, _Salmonella typhi_ is a facultative anaerobe, so it wouldn’t be a perfect progression. Also your lunch would get a bit of a funky smell. I’ll say it again: If something smells odd, **don’t consume it**! As an aside, this fear of warm mayo had gone to idiotic lengths. My sister, for whatever reason, likes her sub sandwiches warm, and asked for an employee at Subway to heat it in the microwave for her. Said employee responded with “I’m sorry, we can’t heat sandwiches with mayo on them”. ARRGGGGG!! ---
**Author:** ![tygre](https://avatars.discourse-cdn.com/v4/letter/t/c4cdca/32.png) [@tygre](https://boards.straightdope.com/u/tygre)\ **Post date:** [October 21, 2002, 7:49pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/4 "2002-10-21T19:49:25Z")
Oh, I don’t know, but then I don’t trust Subway. I’ve had food poisoning **twice** from them. But seriously, yeah, a bologna sammich is okay out of direct sunlight and high heat for a couple hours. If you left it there all weekend, I wouldn’t eat it on Monday, though. 🙂 ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 21, 2002, 8:13pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/5 "2002-10-21T20:13:33Z")
I haven’t been to Subway since I saw a woman carrying out an open bag of shredded lettuce. Maybe she was weak, but she was carrying it in both hands and high up – near her face. Then she sneezed into it and put the lettuce in the bin with the other lettuce. I e-mailed Subway using their online form, but I’ve never received a reply. So I’ve never been back to Subway. I asked for mayo on a hot sandwich once at a small market. The counter guy said, “We usually don’t put mayo on hot sandwiches.” I said, “I guess you’ve never had a hamburger.” So anyway. Nothing wrong with leaving my lunchbox on my desk for four hours with a balogna-and-Best Foods in it? ---
**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:** [October 21, 2002, 8:29pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/6 "2002-10-21T20:29:22Z")
Nothing except for the fact that you eat bologna. ICK! ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [October 21, 2002, 8:34pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/7 "2002-10-21T20:34:21Z")
Fine by me. Except that somebody might steal it… ask yourself, do you really trust your cow-orkers? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 21, 2002, 9:28pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/8 "2002-10-21T21:28:29Z")
> [@](#): > > Nothing except for the fact that you eat bologna. ICK! One of these days I’ll have to get a girlfriend so I have someone to make sure I eat right. ---
**Author:** ![capelover](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@capelover](https://boards.straightdope.com/u/capelover)\ **Post date:** [October 21, 2002, 11:59pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/9 "2002-10-21T23:59:33Z")
Bologna is the only thing I feel is safe enough to send with the kids to school…And I’ve always wondered how it could be safe…But unfortunately for them I’ve always been too chicken and always make them use mustard… I’ve always wondered if I was the only one pondering the bag lunch question… ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 22, 2002, 12:33am UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/10 "2002-10-22T00:33:23Z")
Well, i ate unrefrigerated balogna sandwiches as a kid and I didn’t die. From what others have said, it’s safe enough. (Of course if you were _really_ chicken, you’d send them off with PBJs! 😛 ) ---
**Author:** ![Daikona](https://avatars.discourse-cdn.com/v4/letter/d/8baadc/32.png) [@Daikona](https://boards.straightdope.com/u/Daikona)\ **Post date:** [October 22, 2002, 1:10am UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/11 "2002-10-22T01:10:28Z")
> [@](#): > > \*Originally posted by Johnny L.A. \* > \*\*I asked for mayo on a hot sandwich once at a small market. The counter guy said, “We usually don’t put mayo on hot sandwiches.” I said, “I guess you’ve never had a hamburger.” > \*\* Well, except that hamburgers with mayonaise are an abomination before (deity of your choice here)… 😛 ---
**Author:** ![Tamex](https://avatars.discourse-cdn.com/v4/letter/t/ccd318/32.png) [@Tamex](https://boards.straightdope.com/u/Tamex)\ **Post date:** [October 22, 2002, 3:20am UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/12 "2002-10-22T03:20:29Z")
The no-refrigeration excuse is the reason my parents have always made our school-lunch sandwiches with that abomination known as Miracle Whip. (Mustard was OK, too.) However, if you look at a jar of modern commercial mayonnaise, you will notice that it will only suggest that you refrigerate it “for quality”. It doesn’t say “Keep Refrigerated” like dairy products do. I have heard that there are some people who do not refrigerate it. Yes, they keep it in a cupboard in their house! So, four hours must be nothing, really. There must be enough vinegar and preservatives and perhaps their own toughened immune systems to keep them safe. I personally would question the “quality” of that mayo, though. Ewww… ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [October 22, 2002, 5:38am UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/13 "2002-10-22T05:38:52Z")
> [@](#): > > \*Originally posted by Tamex \* > \*\*The no-refrigeration excuse is the reason my parents have always made our school-lunch sandwiches with that abomination known as Miracle Whip. (Mustard was OK, too.) However, if you look at a jar of modern commercial mayonnaise, you will notice that it will only suggest that you refrigerate it “for quality”. It doesn’t say “Keep Refrigerated” like dairy products do. I have heard that there are some people who do not refrigerate it. Yes, they keep it in a cupboard in their house! So, four hours must be nothing, really. There must be enough vinegar and preservatives and perhaps their own toughened immune systems to keep them safe. I personally would question the “quality” of that mayo, though. Ewww… \*\* Pure mayo doesn’t have enough water to allow bacterial reproduction - it’s all tied up in the emulsion. It can have _Salmonella_ still living in it, but it can’t reproduce enough to make you sick. That’s why you can keep mayo jars unrefrigerated. However, if mayo comes in contact with some other substance that has more water, say, for instance, bread, then you can have bacterial bad news. Which is why you don’t want to leave potato salad sitting out all day.l Same thing can happen if your jar of pure mayo gets contaminated with, say, a dirty knife that leaves behind some other substance that can support reproduction. So don’t go nutso. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [October 22, 2002, 11:05am UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/14 "2002-10-22T11:05:14Z")
> [@](#): > > I haven’t been to Subway since I saw a woman carrying out an open bag of shredded lettuce. Maybe she was weak, but she was carrying it in both hands and high up – near her face. Then she sneezed into it and put the lettuce in the bin with the other lettuce. I e-mailed Subway using their online form, but I’ve never received a reply. So I’ve never been back to Subway. Not that I usually speak up in favour of fast-food chains, but AFAIK all Subways are franchise-operated, so the (lack of) standards in one will probably not have any bearing on those in another. Anyway, most restaurants have the kitchens safely behind closed doors, where they can mistreat the salad with impunity… As for this whole warm-mayo thing, jeez, has everyone gone soft? I’ve never had any problem eating sandwiches that have been out of the fridge for hours. My flatmate, who is even less squeamish about food ickiness, never refrigerates his mayo, and as far as I know has never had any ill effects. Similarly, my parents store butter in a cupboard at room temperature, which makes it much easier to spread. They never poisoned me either. ---
**Author:** ![capelover](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@capelover](https://boards.straightdope.com/u/capelover)\ **Post date:** [October 22, 2002, 11:06am UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/15 "2002-10-22T11:06:47Z")
I am really chicken. forgot the millions of PBJs I’ve sent them with.Bologna was my walk on the wild side. ---
**Author:** ![SirRay](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@SirRay](https://boards.straightdope.com/u/SirRay)\ **Post date:** [October 22, 2002, 1:07pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/16 "2002-10-22T13:07:54Z")
1.) Wouldn’t Microwaving sandwiches with mayo kill bacteria? 2.) Hamburgers are better with mustard, anyway (this is probably a reaction of mine to the usual fast food burgers around here, smothered in greasy, cold ketchup making the bun all soggy). ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 22, 2002, 1:43pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/17 "2002-10-22T13:43:42Z")
**SirRay** : Yeah, but if you put mustard on your burger it sort-of messes with the flavour of the avocado. ---
**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:** [October 22, 2002, 4:57pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/18 "2002-10-22T16:57:19Z")
SirRay, 1. No. Microwaving will not bring the temperature up long enough to kill off all bacteria. Also some bacterial spores (not _Salmonella_ spp. which is a gram negative bacteria) are heat stable, so they need to be put under pressure. 2. Cold ketchup is very yucky. That’s why I don’t refrigerate mine. ---
**Author:** ![Ferret\_Herder](https://avatars.discourse-cdn.com/v4/letter/f/e47774/32.png) [@Ferret\_Herder](https://boards.straightdope.com/u/Ferret_Herder)\ **Post date:** [October 22, 2002, 5:07pm UTC](https://boards.straightdope.com/t/salmonella-lunch-boxes-and-no-refrigeration/133270/19 "2002-10-22T17:07:15Z")
It may also be worth noting that, IIRC, microwaving does not destroy the toxins that certain bacteria - like botulin, admittedly less common than salmonella - can produce.