To avoid wasting meat I've been doing this for years. So far it has worked and now I wonder about the science behind it:
If for whatever reason I end up with a piece of raw meat that starts smelling a bit strong I cut the piece into small chunks, press the chunks to remove as much liquid as possible, put the meat in a pan, cover the meat with water, let the pan uncovered, boil it and wait till the water completely evaporates. At this point, meat looks brownish or darker depending on the meat I use and it doesn't smell as strong. I cook it then as I see fit.
I believe by boiling the meat, convection currents take (at least?) some of the bacteria away and this is a safe way not to waste meat. Is this right? Meat always smells better after 'washing' it this way.
It doesn't matter how you cook it, cooking it thoroughly will kill the bacteria.
However, some bacteria leave toxins behind and cooking won't get rid of those.
Basically don't eat rotten meat, the best way to tell if it's rotten is looking for discolouration and it smelling really bad, although this can also be a good thing in some aged meats like game or beef.
BTW, beef turning brown when the packet is opened is normal. Supermarkets fill the packets with inert gas to artificially keep the meat looking red.
You're taking some considerable risk with that because sometimes the illness is not caused by colonization of bacteria in the body, but by consuming substances that the bacteria leave behind as part of their metabolism. These toxins can be resistant to the temperatures we achieve when cooking meat, especially since boiling isn't going to go beyond 100°C. If anything, you might be diluting the toxins a little, but they're still in the soup. Here's a thorough article on bacteria and their toxins in meat: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152306/
I think it would be a good idea to postpone risky meat and preparation until you speak with a legit expert on the matter.
You're taking some considerable risk with that because sometimes the illness is not caused by colonization of bacteria in the body, but by consuming substances that the bacteria leave behind as part of their metabolism.
No one is pointing out that these “convection currents” created are not taking any bacteria away.
That is only steam from the water added, or water left in the meat- it doesn’t take anything away with it… otherwise you’d have an empty pan and meat vapor all over your kitchen.
As everyone else has said, this is a risky practice due to heat-tolerant bacterial toxins. Here is an article about it, if you want to do some more reading:
The reason the meat smells better after you partially cook it is that you are killing the spoilage bacteria coating the outer surface and washing away or destroying their smelly byproducts. Oddly enough, those aren't the really dangerous bacteria. The ones that cause serious food poisoning mostly do not stink.
Also, cutting the larger chunk of meat up into smaller pieces is a very bad idea. You are just spreading the surface contamination into the muscle. Also, using water as a medium actually limits the upper temperature you can achieve. If you really want to save a piece of meat while minimizing your risk, do this instead:
Leave the cut of meat intact.
Put a high-heat vegetable oil like canola or sunflower oil into a steel frying pan.
Heat it until the oil smokes just a little. The smoke point of sunflower oil is 248 Celsius, whereas water boils at 100 Celsius, so you can easily see why this method is more effective than boiling.
Pick up the piece of meat with two pairs of tongs and place it into the hot pan. Rotate it around until a brown crust forms on the outside. This is called searing.
Remove the meat from the pan and let it cool.
With a clean sharp knife, cut off the seared meat at the surface and discard.
Note that you should not attempt this with poultry, only whole, non-tenderized cuts of beef or pork. This, by the way, is how restaurants prepare beef for serving raw dishes like steak tartar. Or at least that's how they are supposed to prepare it from a food safety perspective.
Note also that this doesn't guarantee that the meat is safe, but raw, whole, non-tenderized cuts of meat are usually only contaminated on the outer surface. Obviously it is safer to avoid the risk altogether, but if you must try to save the meat, this method is far, far better than your current practice.
Bacteria are likely all dead but the toxins that bacteria produce may remain. This is why they can't treat Botulism with antibiotics as it is caused by a toxin produced by the bacterium Clostridium botulinum.
Bacteria are living organisms and like humans they (most of them) cannot survive high temperatures, their proteins denaturate and their cell structure disintegrates. On the other hand, often it is not the organism itself that is dangerous but the toxins they excrete, which could be much more stable. Imagine food that is all covered by mold - you can probably cook or "wash" it as long as you want, you will end up with
serious food poisoning.
I can only recommend to anybody reading this, do not ingest meat that smells suspicious, you can seriously harm your health. And also maybe you'd like to try out a vegetarian diet, just because you read this until the end?
The water doesn't make a difference. What's killing the bacteria is the heat. The water just changes the method of heat transfer. But as others have already said, killing the bacteria may not necessarily make it safe
Not entirely true. While the heat is doing the real heavy lifting, the water as a medium does transfer stuff out of the meat. That's why boiled meat tastes like shit.
Boiled meat tastes bad because you're not adding oil/butter. You're also not applying enough direct heat (plus keeping it too moist) to create the maillard reaction that is needed for a crust to form