View Full Version : Are Most Food Toxins Removed By Boiling?

05-06-2010, 04:37 PM
I was reading something by an anthropologist, who speculates that the advent of cooking meant a tremendous drop in the death rate. The idea was that continuously boiling foods would destroy most of the toxins present in spoiled meats/vegetables. Is this true? If you had some meat that was going "off", would boiling it for hours make the stew safe to eat? Or would you still get sick, if you ate it?

05-06-2010, 04:42 PM
cooking destroys live bacteria though toxins already in the food could still remain. long term boiling and changing out the water a few times could remove water soluble toxins.

05-06-2010, 04:47 PM
When you say 'toxin' do you mean 'unhealthy bad thing,' or 'high-molecular weight poison produced by a living organism'? The latter is how the word is used medically and scientifically, but it's gotten a much vaguer sense in general usage.

With regard to 'unhealthy bad thing,' cooking would kill many pathogens that would otherwise make the eater sick, including bacteria and parasites. It doesn't remove non-living substances (including toxins as defined by medicine.)

05-06-2010, 05:14 PM
Some vegetables have bitter compounds that can be removed by repeated soaking/boiling and then draining/rinsing, until the alkaloids are gone, thus rendering edible something that had previously been inedible.

But I thought the "advent of cooking meat" meant more along the lines of roasting, at least at first, not boiling. It's a simpler and more primitive cooking technique. My understanding was that once proto-humans started cooking meat over fire, it increased the amount of available nutrition, not to mention opening up options for more long-term storate of meat as insurance against insecure food supplies.

05-06-2010, 05:25 PM
Cooking will remove some but not all bacterial toxins. At one end, botulinum is one of the most potent toxins in existence, but it can be destroyed by thorough cooking. At the other end, skin bacteria will happily colonize the food we prepare. If we let it grow that's a bad thing, since the bacterial cell walls themselves are an endotoxin, and cause mild(er) food poisoning. Basically the idea is that certain cell wall components will be recognized by our immune system, which then triggers a purge-digestive-tract-now defensive response. That's the stuff that gives you indigestion when you eat potato salad that spent too long at room temperature.

But those two examples are fairly specific to modern food preparation and handling. Botulism only grows in an anoxic environment like in canned food. Skin bacteria contamination only happens because we handle our food lots, and then keep it around a while. I don't know what sorts of bacterial toxins or pathogens would be present in rotting fruits or vegetables lying on the ground.

05-06-2010, 05:41 PM
The botulism bacteria are destroyed by boiling, but the toxins produced by the bacteria are not. So boiling when the food is canned in the first place will protect it, but once it's spoiled, it's too late to do anything to fix it.

05-06-2010, 06:20 PM
The botulism bacteria are destroyed by boiling, but the toxins produced by the bacteria are not. So boiling when the food is canned in the first place will protect it, but once it's spoiled, it's too late to do anything to fix it.

At least according to the wiki botulism spores are not destroyed by boiling but the toxin is denatured by boiling.



05-06-2010, 06:41 PM
Beans contains various substances that will make you sick if you eat them raw, specifically phytohemagglutinin (http://en.wikipedia.org/wiki/Phytohaemagglutinin). As few as five raw kidney beans can cause poisoning. Boiling, for beans, does render them safe to eat.

Some other foods, such as pokeweed and quinoa, contain sapnonins (http://en.wikipedia.org/wiki/Saponin). proper cooking - usually boiling with multiple water rinses - removes these. Eating raw pokeweed will usually induce vomiting. A two-hour boil with at least one water change makes it into a tasty and edible green. Most quinoa sold in US grocery stores has already had its saponins removed.

Soaking/boiling also removes the tannins in acorns, making them useful to humans.

So yes, some food toxins are removed by boiling. This opened up many more food plants to the human race. However, not all toxins or poisons are removed or inactivated by boiling.

Send questions for Cecil Adams to: cecil@straightdope.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright 2018 STM Reader, LLC.