1. Raw flour can carry E. coli
In unwelcome news for cookie-dough fans, flour was recently confirmed as the source of a serious E. coli outbreak in the United States in 2016. Certain strains of these bacteria can be toxic, causing stomach cramps, bloody diarrhea, vomiting and, in extreme cases, kidney failure. Scientists knew E. coli could thrive in undercooked meat, but they were surprised to find the bacteria in dry flour. To be safe, health authorities now recommend washing your hands thoroughly after handling flour and abstaining from eating raw or unpasteurized dough.