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I put some uncooked stew meat and veggies on this morning and left for 5 hours. When I came home I realized it was only set on warm. Is my meat safe to eat? I have now put it on the stove to cook.

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marked as duplicate by Aaronut Oct 14 '13 at 18:39

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Where did you "put ... on" this meat? What does "warm" mean? –  Marti Dec 2 '11 at 21:03
    
@Marti: I'm sure she's referring to a crock pot - that's the only cooking appliance people will generally leave on for an entire day and leave the house, and has an explicit "warm" setting. If I'm wrong, then the OP can retag. –  Aaronut Dec 3 '11 at 17:40
    
@Aaronut: While my new crock pot will get food over 140F/60C at its "low" setting (vs "high"), my friend's crock pot does not have the oomph to get past lukewarm. Without a thermometer, you simply can't tell. –  Bruce Goldstein Dec 9 '11 at 21:03
    
This is not a duplicate of the linked question! Another case of an overzealous librarian. –  uosɐſ Jun 10 at 19:00

2 Answers 2

jdev is right about the USDA's cooking temps, but I would be very surprised if a warmer setting got your food above 140 degrees F (60 C). When food is under that temperature, bacteria reproduce almost geometrically. Later cooking will reduce your risk but not eliminate it. In your case, if you didn't spend quality time in your bathroom last night, you dodged a bullet.

Most of the bugs that make us sick don't grow well below 40 degrees F and are killed when heated above 140 degrees F. In particular, E coli, Salmonella (various types), Vibrio (various types), and Listeria monocytogenes, which are the most common of the bacteria that give us food poisoning, are all killed by heat. We tend to get sick from them mainly because we ate raw/undercooked food or the bugs got into the food after the cooking is done.

There are a few nasties, however, that can leave behind heat-stable toxins even after they have been killed -- most notably, Staphylococcus aureus. Staph a is a very common bacteria, the source of many illnesses. If your food was contaminated with Staph a before you cooked it, and they had time to multiply, then even though the bugs themselves would have been killed by the cooking, their toxins would still be in the food -- and you would have gotten to know your toilet very, very well (symptoms at both ends of the GI tract begin within about 1-6 hours after eating and are severe, but they resolve in 48 hours).

As a general rule, don't eat or use meat, dairy products, or cut fruits/vegetables that have been in the "danger zone" (40-140F) for over 4 hours, even if you planned to cook it later. (Obviously, there are a lot of exceptions to this rule, but that's another long post.)

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It all depends on the temperature of your warmer.

The USDA recommends the following minimum internal temperatures:

  • Cook all raw beef, pork, lamb and veal steaks, chops, and roasts to a minimum internal temperature of 145 °F as measured with a food thermometer before removing meat from the heat source. For safety and quality, allow meat to rest for at least three minutes before carving or consuming. For reasons of personal preference, consumers may choose to cook meat to higher temperatures.

  • Cook all raw ground beef, pork, lamb, and veal to an internal temperature of 160 °F as measured with a food thermometer.

  • Cook all poultry to a safe minimum internal temperature of 165 °F as measured with a food thermometer.

You should be able to verify all is well with a cooking thermometer.

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And holding temperature is 140 degrees F. If it was warming at a temperature less than that, it may not be safe. –  thursdaysgeek Dec 1 '11 at 0:23
    
Even if you raise the internal temperature to a sufficient temperature after the fact, that may not mean it is safe to eat if the meat sat too long at too low a temperature beforehand. The reason is: Heating to above 140°F will get rid of most of the harmful bacteria, however, the problem is that during the time that it sat below 140°F those bacteria could have produced deadly toxins that do not degrade until much, much higher temperatures. –  ESultanik Dec 1 '11 at 14:52
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It's even worse than what @ESultanik says because dangerous bacteria grow much faster at body temperature (37° C / 100° F) than at room temperature (20-25° C). If the "warm" temperature is something like 100-120° F then you've basically created a giant incubator. –  Aaronut Dec 1 '11 at 20:26
    
plus heat doesn't break down toxins. Once they are in there, they are there forever... well at least till you put em in your body and get sick. –  sarge_smith Dec 3 '11 at 18:53

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