I mean, when we eat a hamburger, say, we cook it long enough to kill the bacteria. So, is it live bacteria that are bad for us? Is this because they continue to thrive inside us and in doing so, produce toxins? If so, why don’t these toxins make us sick in cooked meat where the bacteria were? Does cooking also destroy the toxins?
Because you kill the bacteria before they have a chance to create enough toxins to pose a threat. Given enough time, bacteria would build up a lethal amount of toxins in raw meat. Cook that meat (aka rancid) and it is still no better than raw meat. In fact, raw meat is not necessarily bad for you. It’s just the possibility of large amounts of particularly nasty bacteria or viruses that is bad. thats why we cook the food. Well, and for texture and flavor. But mostly its because “average” raw meat possibly has too many bad bacteria on it.
Look up “steak tartare” or “carpaccio”. It’s raw beef. High quality raw beef.
And no, cooking does not destroy toxins, in case that point was unclear from my post.
Generally speaking, you’re worried about picking up an infection - that is, bacteria set up shop inside your body somewhere and start growing and making stuff that makes you sick. Killing the bacteria in the food before it gets to your gut stops that whole process. Generally speaking, bacteria won’t be able to grow well enough on your food to have made enough stuff to make you sick.
Of course, this being biology, there are lots of exceptions to every rule, and some kinds of bacteria can sometimes make enough stuff to make you sick regardless. But that’s the general idea. Usually. Most of the time.
The same principle applies to blood transfusions. Your blood contains immune cells and antibodies that might attack the donated blood. The donated blood also contains antibodies and immune cells that might attack your blood. But in practice you only have to worry about the former and not the latter because the antibodies in the donated blood are at most a finite problem while the antibodies in your blood are part of a system that can make an arbitrarily large number of antibodies if provoked.
I think it probably does destroy some of them. Toxins produced by bacteria are going to be organic molecules, probably peptides in a lot of cases, and many organic compounds (and nearly all peptides) are quite heat labile.
Of course you are right that not all types of bacterial toxin will be destroyed by cooking (conceivably, some might even be made more toxic), and that the killing of the bacteria themselves plays a much more important role in food safety.
Of course botulism comes from the poison secreted by bacteria. In very very small doses it’s a cosmetic aide. Cooking will destroy both the bacteria and the poison, IIRC.
Most organic molecules are badly disrupted by heat. It’s how we get “cooked” meat from raw, it kills bacteria, and significantly alters most organic material. High radiation does the same thing, blasting breaks in long organic molecule chains; once too many are disrupted, life cannot continue.
In the famous tuna-gate scandal many decades ago in Canada, it was mentioned that rotten tuna, properly processed, was perfectly healthy to eat even if it was ( ) unappetizing. The fisheries department told inspectors to stop rejecting so much tuna just because they though it was bad. An opposition member taunted the minister of fisheries that he was gambling with soldiers’ lives (ordering the defnse department to buy unsalable tuna to support the local fish plant). The minister challenged the member to make the same statement outside parliament, where immunity did not apply and he could be sued for libel. A radio commentator explaining the situation said you could eat feces with no ill effects if it had been properly pasteurized and canned. The opposition member declined to make the “soldiers’ lives” comment outside of parliamentary immunity.
A case of winning the battle, but losing the war…
Staph enterotoxins and one of the toxins from B. cereus is stable to heat. Bacillus cereus and the various clostridia make spores that can survive and germinate afterwards if the foodstuff is temperature abused. Most of the gram-negative food-borne pathogens (E. coli, salmonella, shigella) will grow inside you and make toxins.
How do carrion-eaters (like vultures and hyenas) avoid getting sick from their meals?
Vultures will eat rotting carcasses, which must be loaded with toxins-yet they thrive.
A fairly good article Bending the Rules on Bacteria and Food Safety - NYTimes.com today. I found it fairly consistent with what I remember of was taught in medical microbiology a half century ago. Somewhere down there they even get into heat resistant toxins.
A few simple answers, all of which probably contribute:
-They’re evolved for it. Their digestive and immune systems are adapted to the diet they eat.
-“Carrion” doesn’t necessarily mean “rotten”. I’m speculating here, but there’s probably a level of decomposition at which even a vulture would go, “Uh, yeah…no thanks”. I think generally, there’s not a huge amount of time between death and eaten up.
-I’d want to see some hard numbers before accepting that all “rotting carcasses…must be loaded with toxins”.
-Who’s to say carrion eaters don’t get sick from time to time? They don’t put a strain on our health system, so we wouldn’t really notice.
Hrm…doesn’t seem quite right for a GQ answer. Maybe the “probably” and “think” should stay in imho and mpsims where they belong.
If what you got ain’t even facts, don’t bring it to the table. Wrong facts, sure. Them’s we can talk about. But guesses, musings and inferences? Nope.
With all due respect, Echo, I think GQ can make room for logical conclusions and reason, even if it’s not rooted in a citation from someplace else and even if it looks at first blush like idle speculation. I think** njtt **was drawing a reasonable inference from established fact. In my view, that’s not a violation of our very high principles here.
Did you read my very next sentence, where I justify my claim? It is indeed a fact that bacterial toxins are organic molecules, and that organic molecules are, in varying degrees, heat labile. I was not guessing.
Bacteria cause food borne illness via two methods: infection and intoxication.
Infection is when ingested bacteria multiply in the gut and cause disease. These illnesses typically have a 12-48 hour incubation or lag time from the moment of ingestion to onset of symptoms. Cooking food to temperatures sufficient to lower the bacterial count to numbers below that needed to infect prevent illness in these cases.
Intoxication is when bacteria produce a toxin while still in the food itself that causes illness when ingested. These illness typically have a latency time of 15 minutes to several hours. Getting nausea and vomiting 2 hours after eating egg salad at a picnic is an example of this. In that setting, Staphylococcus aureus or Bacillus cereus are the typical culprits. The effect of cooking on preventing these diseases depends on the toxin. Some toxins are vulnerable to heat, and are termed heat labile. Others are resistant, and are deemed heat stabile. For example, enterotoxigenic Escherichia coli (ETEC) produces both a heat stabile and a heat labile toxin. You should know, however, that all proteins degrade with enough heat, even heat stabile toxins. Its just that it takes so much heat in cooking that food would be ruined long before the toxin is inactivated so it is deemed heat stabile. So yeah, some toxins are inactivated by heat, others are not.
For example, IIRC the stomachs of vultures have twice as high a concentration of hydrochloric acid as ours do.