Suppose I have some food that became unsafe or contaminated by any means besides explicitly adding dangerous substances. It could be past the expiration date, or handled unsafely by leaving at room temperature too long, etc. Another possibility to consider is botulism from damaged cans.

Would it be possible to resurrect food from these situations, making it safe, by sufficiently heating it?

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    I highly doubt it, once food's gone off, it's gone off and you're likely to regret the choice to try reheating it. – amanda witt Feb 24 '13 at 3:01
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    If the spoilage has messed with the taste or texture (and it may well have), safe may not mean you'd want to eat it. – Cascabel Feb 24 '13 at 7:01
  • I'm much more concerned about the safety than its taste; though obviously if it tasted off or bad I would discard it. The problem is that contrary to popular belief, smell and taste can result in false negatives when trying to determine if something is safe to eat. – Jeff Axelrod Feb 24 '13 at 15:19
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    How expensive is this food that it's worth the risk to even attempt this rather than just throwing it out? – Aaronut Feb 24 '13 at 19:50
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    Also, does this question really break any new ground that wasn't covered in Why is it dangerous to eat meat which has been left out and then cooked? or various similar questions? – Aaronut Feb 24 '13 at 19:55

That'd depend on the exact microbes involved in making it unsafe (or, since you probably don't know, the short answer is "no").

There are basically two ways microbial growth makes food unsafe: either by the presence of the microbes themselves, or by toxins the microbes create. Sufficiently heating the food will kill enough microbes, so those ones will be taken care of. Unfortunately, some of the toxins are heat stable, and it just isn't possible to heat the food to a high enough temperature to destroy these toxins without turning the food to charcoal.

The FDA's Bad Bug Book gives details about specific pathogens and their heat-stable and heat-labile toxins.


As others have said, this will depend on what has caused the food to spoil. I would add however, that there is a third route that has not been mentioned - spores. Spores are basically kind of the bacterial equivalent of a space suit - bacteria can form spores when conditions are bad and as spores can often survive extremely hostile conditions, including heat, acid, bleach, etc. Spores are especially important in the case of botulism.

If the food has spoiled due to botulism, there is not much you can do to make sure it is safe. You may be able to kill the bacteria and destroy toxin directly in the food by prolonged heating (at least according to the USDA fact sheet below), but even so the spores of the bacteria are heat resistant. If you consume the spores, they can activate and become live bacteria which will then produce the toxin directly in your body, and it is the toxin which can cause serious or fatal damage.

For a good summary of botulism and botulinum toxin, see: https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/foodborne-illness-and-disease/clostridium-botulinum/ct_index

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    From the link you posted, "these spores are found everywhere. While the spores are generally harmless, the danger can occur once the spores begin to grow out into active bacteria and produce neurotoxins.". The spores aren't a problem (except possibly children under 1 year in age). – derobert Mar 1 '13 at 16:37
  • Spores would also be a problem if you were to re-cook and then save leftovers again, thinking it was safe. The spores can then reactivate and grow and produce toxins, basically providing a giant head start to bacterial growth. – Cascabel Oct 31 '17 at 19:53

Man! Don't even risk it! Toxins, spores, and the like reap peoples lives every day.

If any question on a food in fridge throw it out! Your freezer is your freind in barf, sweat, hurt and die prevention, Its easy and safe right? Otherwise don't take anyone's word on refrigerator spoilage made good to eat again tactics.


It really depends on the toxin, but honestly, since you probably will not be able to know that in advance, don't bother, just throw it out.

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    You've posted some good answers, but you've also posted a few like this that are essentially just information that was already in another answer. Your answers will be more valuable (and collect more upvotes) if they provide new information. – Cascabel Mar 1 '13 at 4:59

Are you nuts? Don't even think about it, bin it.

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