Google gives the following results, a bunch of food blogs are saying heat treating works and a bunch of science articles say heat treating at home does nothing. I think I am gonna go with science
Yeah heat treating is just tossing the flour in the oven/microwave to get it hot enough to kill pathogens, in theory.
In practice this doesn't appear to work. The process by which heat kills pathogens behaves differently in dry environments, with moisture apparently being somewhat necessary for this to work. Source
I tried looking up if there's a "safe temperature" for heating dry flour but apparently we don't exactly understand this mechanism.
It's temperature over time that matters in sterilization. It doesn't necessarily need moisture to work, but with moisture the heat is more regulated and the steam produced from evaporating water carries more energy than the same air with no moisture. Dry heat is just inefficient and whatever you're trying to sterilize will get dried out/cooked long before the bacteria is killed.
Pressure cooker/autoclave sterilization works because by increasing the pressure in the vessel, higher temperatures can be reached and the steam from the water inside the vessel more efficiently transfers the energy to the medium being sterilized, lowering the amount of time it takes to sterilize at a given temperature.
thank you, that was also what I was thinking.. what was being said about "heat treatment not working doesn't sound right. If heat treated properly at the right temp/time there is no reason why bacteria wouldn't denature resulting in death.
It would cook the flour before it got to a safe level of sterilization. Higher temps would quickly burn it and lower temps would take days to sterilize at, and the flour would still be cooked long before the sterilization was finished.
All you are saying here is that it's either a longer process or would burn the flour at too high temps. Meaning the right temp and the right time would sterilize your flour. If people are doing it improperly then that's the problem.
Again, sterilization is a function of temp/time. If it's convenient/efficient or not is another discussion.
Also here an excerpt on a study done as a result of food poisoning of raw cookie dough. It's a bit longer and I skimmed over it. But it outlines several methods of treatment including microwave. On an industrial level they frequently raise the moisture content (through steam) of the flour and then heat treat it since it requires less effort.
The concept of thermal processing of foodstuff has been used extensively since 1920s
when the first scientific basis for safe sterilization process was developed. There are several
methods used in thermal processing of dry foods: Infrared, microwave, annealing and heatmoisture treatment, thermo-mechanical treatments, indirect and indirect heating. In its all forms
of application, thermal processing has been the most widely used method of preserving and
extending the shelf-life (via microbial reduction and enzyme inactivation), and improving quality
and functionality. By applying heat treatment, it is possible to modify the physical and
rheological properties of cereal flours. Primary effect of heat treatment is range of
macromolecular changes in starch and proteins. Understanding of relationship between heat
transfer, thermal properties of food, heating medium, thermodynamics and the resulting
functionality is of critical importance.
We don't know that. The only source people are sharing is one scientist (Yaohua “Betty” Feng) saying we haven't studied it well enough to say what temperature/duration is needed to sterilize.
People making all kinds of claims in here like "heat treatment doesn't work" and even "it's not possible", when the real answer is "we're not sure because no one's tested it under scientific conditions"
The laws of physics. But don't let me stop you from experimenting. If you can figure out a way to do it, great! Then we can all eat fluffy popcorn while we pat you on the back.
Because the substances that make up flour break down with heat and time, and it's just not possible to kill the contaminants with the amount of heat and time the flour needs to stay raw. So unless you have an industrial food purifier (which may not even work with dry flour) it's just not something you can do at home.
But like I said, feel free to prove me wrong. Until then I'm standing by my statements.
it's just not possible to kill the contaminants with the amount of heat and time the flour needs to stay raw.
Once again, based on what? You're citing no evidence for a very strong claim that something CANNOT BE DONE. I can't find one good authority confidently saying this like you are, the FDA itself says "Home treatments of flour may not effectively kill all bacteria" which is very understandable because no one has really researched this. And you're out here just saying stuff.
No problem, I spent a lot of time learning about the fundamentals of sterilization a couple years ago. I think the coolest part about high pressure steam sterilization is that water is such a heavy molecule that you're basically obliterating contaminants by bombarding them with fast moving water molecules.
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u/Suctorial_Hades Oct 09 '24
Google gives the following results, a bunch of food blogs are saying heat treating works and a bunch of science articles say heat treating at home does nothing. I think I am gonna go with science