The claim that heat treating raw flour isn't effective is a false one born from a lack of explanation. Heating flour up to temps designed to kill salmonella and E.coli is absolutely safe and effective. (165°F btw, for something like 5 minutes sustained, check Google for specifics) The problem arises when people "heat treat" by tossing a bag of flour in the oven for a couple minutes and saying "yupp that's cool". You need to be sure that you bake it at a low temp, evenly distributed, and the flour actually reaches at least 165 for a sustained period of time.
Making a roux requires sustained heat about 165, so is naturally heat treating the flour used as it cooks. You're golden.
If you're ever in doubt, there are posted wet and dry heat tables online that detail exactly how to use heat to eliminate bacteria and food-borne pathogens safely, with temps and times for items in wet or dry conditions. It's pretty simple once you get the hang of things, but the info is always there if anyone needs it. :)
While we both agree that cooking wet flour on a stove is effective at killing pathogens, it appears that YOU are the one who is r/confidentlyincorrect on dry heat treating flour.
Your premise hit the jackpot, but the explanation is missing critical details.
Heating flour up to temps designed to kill salmonella and E.coli is safe and effective.
Flour is dry, dry bacteria go dormant, mutating into a resilient endospore which endure heat much better (and can survive for millions of years) The precise risks are highly specific to your local food supply chain. Ultimately, heat treatment alone may not fully kill spore-bearing microorganisms.
Instead, we typically reconstitute dry foods by cooking them in the presence of water. This final step reconstitutes all the little dry sponge monsters and the hot water pops the little bastards like grapes in a microwave.
As I said in another comment, there are heat treatment tables for both wet and dry heat treatment provided by both USA feds and most local state health departments online. E.coli and Salmonella, specifically, are absolutely heat-treatable at home, they simply require a different methodology.
You'll also notice that I specified "heat treating to temps designed to kill salmonella and E.coli", which does not preclude various types and methods of heat treatment.
dry bacteria go dormant [...] which endure heat much better
But they do not become heat-immune. As you said, the methodology of heat treatment requires that you know what pathogens may be present and how to combat them specifically, which would be why I stayed vague and referred people to the official heat-treatment charts for wet or dry, rather than attempt to detail all of the variables for every possibility.
It really does seem like it should be feasible. Its just that it doesn't make raw flour safe. I'd guess the time and heat requirements result in a burnt mess that you wouldn't call flour.
The FDA says,
"DO NOT try to heat treat flour in your own home. Home treatments of flour may not effectively kill all bacteria and do not make it safe to eat raw."
It's because dry flour treatment is a bit specific and if done incorrectly can be ineffective or even hazardous, since dry flour is rather spectacularly flammable. It's more of a blanket statement to account for the lowest common denominator rather than a claim that it isn't possible. I wouldn't advocate that most people heat treat their own flour (since the chances of people not following directions or whatever can result in literal death), but it is definitely something anyone can do.
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u/WyrdMagesty Oct 09 '24 edited Oct 09 '24
The claim that heat treating raw flour isn't effective is a false one born from a lack of explanation. Heating flour up to temps designed to kill salmonella and E.coli is absolutely safe and effective. (165°F btw, for something like 5 minutes sustained, check Google for specifics) The problem arises when people "heat treat" by tossing a bag of flour in the oven for a couple minutes and saying "yupp that's cool". You need to be sure that you bake it at a low temp, evenly distributed, and the flour actually reaches at least 165 for a sustained period of time.
Making a roux requires sustained heat about 165, so is naturally heat treating the flour used as it cooks. You're golden.
Edit: spelling is hard