# How dangerous is day-old, unrefrigerated pizza? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [November 8, 2010, 5:08pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927 "2010-11-08T17:08:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [November 8, 2010, 5:08pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/1 "2010-11-08T17:08:25Z")
In separate cartons, there are slices left of plain, pepperoni, sausage, onion, and chicken pizza. There is also a carton with two slices–one slice with pepperoni and one plain, but they were from a 1/2 & 1/2, so they are touching. They’ve been out all night, unrefrigerated in a room. It’s 16 hours later. Are any of them safe to eat? ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [November 8, 2010, 5:14pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/2 "2010-11-08T17:14:21Z")
I had a roommate that left pizza out unrefrigerated. It didn’t seem to bother him. He’d often finish off a pizza the next day. He even liked it unheated. I never would eat the leftovers myself. But, my stomach gets tore up easily anyway. YMMV ---
**Author:** ![Alpha\_Twit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alpha_twit/32/265_2.png) [@Alpha\_Twit](https://boards.straightdope.com/u/Alpha_Twit)\ **Post date:** [November 8, 2010, 5:14pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/3 "2010-11-08T17:14:35Z")
_I’d_ probably microwave and eat them but I’m not going to pretend that doing so is in anyway smart or healthy. The smart money says to discard them. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 8, 2010, 5:18pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/4 "2010-11-08T17:18:04Z")
Since we don’t know all the factors involved, I don’t think this question can be answered factually. Moving to IMHO from GQ. Colibri General Questions Moderator ---
**Author:** ![Fried\_Dough\_Ho](https://avatars.discourse-cdn.com/v4/letter/f/a88e57/32.png) [@Fried\_Dough\_Ho](https://boards.straightdope.com/u/Fried_Dough_Ho)\ **Post date:** [November 8, 2010, 5:19pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/5 "2010-11-08T17:19:43Z")
I had an Ex who loved this - he would keep them out for more than a day (a two or three!) until the ends started to curl up. He would call those Elf Shoes and lived on them for several years. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [November 8, 2010, 5:20pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/6 "2010-11-08T17:20:17Z")
I would never advise anyone that it’s perfectly safe to eat. That said, I would also not hesitate in eating it. ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [November 8, 2010, 5:22pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/7 "2010-11-08T17:22:38Z")
This would be an excellent Mythbusters experiment. Test several fast foods, pizza, burger, burrito etc. the next day for bacteria levels. They’ve done a few bacteria tests before. ---
**Author:** ![Yorikke](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yorikke/32/4335_2.png) [@Yorikke](https://boards.straightdope.com/u/Yorikke)\ **Post date:** [November 8, 2010, 5:22pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/8 "2010-11-08T17:22:52Z")
I always, always leave pizza out, and eat some the next day. Coincidentally, the only issue I had was a couple of weeks ago. It involved chicken pizza. Though I have left the same pizza out a half-dozen times before, with no problems, this time, I had some relatively minor diarrhea and vomiting issues. In general, not a problem, but I will think twice before doing it with chicken in the future. ETA : I have an exceptionally strong stomach, in general. Joe ---
**Author:** ![joebuck20](https://avatars.discourse-cdn.com/v4/letter/j/74df32/32.png) [@joebuck20](https://boards.straightdope.com/u/joebuck20)\ **Post date:** [November 8, 2010, 5:29pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/9 "2010-11-08T17:29:42Z")
I used to eat day-old unrefrigerated pizza all the time in college (can’t fit much in those dorm room mini-fridges) and never had any problems. It actually keeps fairly well for three or four days, though I wouldn’t recommend keeping it around much longer than that. ---
**Author:** ![AClockworkMelon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aclockworkmelon/32/10803_2.png) [@AClockworkMelon](https://boards.straightdope.com/u/AClockworkMelon)\ **Post date:** [November 8, 2010, 5:30pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/10 "2010-11-08T17:30:00Z")
Are you kidding me? What you’re describing is the best kind of pizza! ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [November 8, 2010, 5:35pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/11 "2010-11-08T17:35:09Z")
> [@aceplace57](#): > > This would be an excellent Mythbusters experiment. > > Test several fast foods, pizza, burger, burrito etc. the next day for bacteria levels. > > They’ve done a few bacteria tests before. I’m not sure this is meaningful without knowing the point at which the bacterial level becomes dangerous. And even then, doesn’t it depend on the particular species of bacteria? In moderate to cold climates, I’ve done the pizza-next-day thing since I was a kid and never had any issues. ---
**Author:** ![kittenblue](https://avatars.discourse-cdn.com/v4/letter/k/ba8739/32.png) [@kittenblue](https://boards.straightdope.com/u/kittenblue)\ **Post date:** [November 8, 2010, 5:41pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/12 "2010-11-08T17:41:11Z")
I wouldn’t eat the chicken one (even when it is hot and fresh) but I’d have no qualms about the pepperoni one. Heck, it’s practically the same ingredients as pepperoni bread, and that stays at room temperature all the time. ---
**Author:** ![minlokwat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minlokwat/32/2844_2.png) [@minlokwat](https://boards.straightdope.com/u/minlokwat)\ **Post date:** [November 8, 2010, 5:52pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/13 "2010-11-08T17:52:10Z")
Weirdness. This topic just came up this past weekend. I recounted how once in college I left some pizza out unrefrigerated, overnight and the next morning decided to enjoy some. I have as strong an internal processing unit as the next guy but within the hour that pizza came back up the way it came in. Fortunately I was no worse for wear and chalked it up as lesson learned. Should you choose to indulge please report your findings to the rest of us as I’m a bit curious. ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [November 8, 2010, 6:45pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/14 "2010-11-08T18:45:36Z")
Like others have admitted, I too started doing this in college 13 years ago. Pizza was ridiculously cheap, like $5 for a large pie, so I would get one or TWO and just keep them around in their boxes until they were done. I still do it. Almost every Friday I’ll get a large pizza (pizza is one of those things that ends up being cheaper the more you buy) and let it sit out Friday and Saturday nights and eat it over the weekend. I haven’t died yet and I’ve been doing this for years. It’s not usually a meat pizza, tho - or if it is, it’s sausage or pepperoni and nothing is going to kill sausage or pepperoni. ---
**Author:** ![BigBertha](https://avatars.discourse-cdn.com/v4/letter/b/d78d45/32.png) [@BigBertha](https://boards.straightdope.com/u/BigBertha)\ **Post date:** [November 8, 2010, 6:48pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/15 "2010-11-08T18:48:21Z")
Like others, I’ve done this before, but only when I’d run out of aluminum foil. Do you guys not have any? ---
**Author:** ![EmAnJ](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@EmAnJ](https://boards.straightdope.com/u/EmAnJ)\ **Post date:** [November 8, 2010, 6:49pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/16 "2010-11-08T18:49:56Z")
For some reason, I’ve had it in my head that anything with a tomato base must be refrigerated or it’ll go bad. So if I leave out pizza, or spaghetti sauce or something like that overnight, I toss it. I’m not sure _why_ I think this, but it’s just a habit now. So, I probably wouldn’t eat it, but I’m sure it won’t kill you. ---
**Author:** ![Mister\_Owl](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@Mister\_Owl](https://boards.straightdope.com/u/Mister_Owl)\ **Post date:** [November 8, 2010, 6:54pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/17 "2010-11-08T18:54:13Z")
Somebody set up a poll. I’d like to know how this divides along the sexes. Incidentally, pizza is best when it has be properly aged overnight on the counter or table. ---
**Author:** ![Dung\_Beetle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dung_beetle/32/7945_2.png) [@Dung\_Beetle](https://boards.straightdope.com/u/Dung_Beetle)\ **Post date:** [November 8, 2010, 6:58pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/18 "2010-11-08T18:58:07Z")
We always leave the pizza out and finish it the next day. Truly, left to my own devices, I would lean towards refrigeration, but my husband doesn’t believe it’s necessary and he seems to be right. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 8, 2010, 7:09pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/19 "2010-11-08T19:09:28Z")
> [@EmAnJ](#): > > For some reason, I’ve had it in my head that anything with a tomato base must be refrigerated or it’ll go bad. Most restaurants leave ketchup bottles on their tables without refrigeration and have no problems. A lot of tomato-based sauces are probably acid enough to inhibit bacterial growth. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [November 8, 2010, 7:17pm UTC](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927/20 "2010-11-08T19:17:53Z")
One of the guys often brings a pizza to watch NFL on Sunday. Usually the box is left on the coffee table in the living room and I’ll have a slice or two later that week. [Next page](https://boards.straightdope.com/t/how-dangerous-is-day-old-unrefrigerated-pizza/559927.md?page=2)