Raw flour comes from milled wheat grown on wheat plant farms in fields all around the world, feeding billions of people every day. With flour we bake breads, cakes, biscuits, pies and innumerable other wheaty foods. Since most of these are cooked, however, there is no issue at all. Today’s new health concern touches only raw, uncooked flour.
We come into contact with raw flour in these forms: (1) packaged flour powder; (2) homemade dough; (3) prepacked dough. If you consume flour in its powdered form, for example if you want to taste it for some reason, or by accident; if you consume homemade dough; or if you consume prepackaged dough, then you are exposing your insides to pathogens which have got inside the wheat plants that produced the flour. Certain pathogens, such as those from animal waste, will remain in the flour after it has been milled. Eating contaminated, uncooked flour will pass the pathogens on to you, and you may get sick.
No one knows what actually causes flour to become infected (perhaps it comes from animal feces, perhaps from untreated water irrigation, perhaps from cross-contamination at the mill), so the problem doesn't look like it is going away anytime soon. Also flour’s capacity to cause illness is not much under the spotlight. The Produce Safety rule that puts attention on certain high risk foods, in order to stamp out outbreaks does not cover flour. A possible solution to the problem is heat treatment of flour prior to sale. However, this is considered a non-starter because of a lack of infrastructure and technology to implement this change.
The best advice for you to avoid this worrying development is to avoid eating raw flour and dough wherever it's offered to you. Though this may be easy for you to do, it may be harder for other people. Think, for example, of the recent tread of certain family restaurants giving young children edible dough to play with while they wait for their meals. Be on the lookout for situations like this.