As a follow-up to this question about the safety of raw flour, and to possibly update this question about eating raw cookie dough:

  • Is it possible/how can I pasteurize raw flour, at home, to kill any E. coli that may be present?
  • If possible, what other effects (e.g., flavor, color, texture) if any, will this have on the flour?
  • 2
    You might add why you want to do this. Is it because you want to use flour in something that won't be cooked?
    – user3169
    Jul 8, 2016 at 3:29
  • 1
    Here's a useful article that summarizes some of the advantages/disadvantages of current ways to limit microbial growth in flour. I don't know anything about attempts to standardize home pasteurization of flour yet, but it is done commercially and some large companies use it for various applications.
    – Athanasius
    Aug 12, 2016 at 20:52

2 Answers 2


In principle, I don't see why you couldn't take the flour to safe temperatures just like any other food. You'd have to reach temperatures which break down proteins, something like 165 F or 75 C should be sufficient (it's good enough for meat).

This will break down the proteins in the flour too, so I would expect it to behave like standard browned flour (although browned flour is taken to higher temperatures than that). It won't be suitable for making doughs and batters, or at least will perform much worse. You can use it for not-completely-white roux, or for fermenting bosa, or any other standard use of preheated flour.

  • If the purpose is to make cookie dough to be used "raw" in ice cream, would it taste weird?
    – Catija
    Jul 8, 2016 at 13:51
  • @Catija as I said, it is unlikely that you can make any dough with it. It will bind much less.
    – rumtscho
    Jul 8, 2016 at 13:54
  • I had assumed you meant doughs and batters that would be cooked. Most raw doughs seem wet enough I didn't realize it would be an issue.
    – Catija
    Jul 8, 2016 at 13:55
  • 1
    But people leave eggs out of dough entirely if they aren't intending to bake it. Flour that has been heated doesn't look very different than raw flour... Based on what I've seen when I baked bread. Which is, admittedly not likely the best example.
    – Catija
    Jul 8, 2016 at 14:04
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    @Catija - I think rumtscho may be exaggerating the impact a bit here. Yes, the protein damage will be sufficient to cause problems if you wanted to, say, bake bread. But you should still be able to make cookie dough with it. Nestle has been using pasteurized flour in its pre-made cookie dough recipes for several years, after a previous E. coli outbreak in 2009 traced to people eating raw pre-packaged cookie dough. Pasteurized flour is recommended for people making uncooked dough products like use in ice cream. I don't know standards for home processing, but it's clearly used commercially.
    – Athanasius
    Aug 12, 2016 at 20:49

I recently ran across this interesting article about using a sous vide to make safe-to-eat raw cookie dough.

According to the article, flour needs to be brought to 160 F to make it safe for raw consumption. She uses her sous vide to do this though admits it takes a really long time for the flour to come to temperature (four hours). She links to another article that was able to do the same thing in a 1200 watt microwave in 55 seconds... which gives us another option for home flour pasteurization.

As pointed out in the second article:

Heating flour to this temperature runs the risk of burning the flour, therefore heating must be done carefully to ensure flour does not get too hot and burn. Also, heating the flour to 160 degrees F destroys some of the gluten in the flour and therefore would make the flour no good for baking. However, the flour is still useful for creating treats that will not need to be baked.

So, if you want flour that can be used in unbaked products (cookie dough), both the sous vide and microwave are options.

  • 1
    The microwave option, while convenient, would be very dependent on the microwave. Many would get some patches too hot while others are still cold. Using a thermometer to stir might be a good idea.
    – Chris H
    Nov 4, 2016 at 14:35
  • Yeah, the full method is explained in the article. And I specifically included the wattage of the test microwave for that reason. I can include more of the article here if it will help.
    – Catija
    Nov 4, 2016 at 14:37

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