It’s cookie season and federal health officials are reminding Americans not to eat raw cookie dough, tempting as it may be, writes MaggieFox of NBC News.

There are two reasons raw cookie dough can make you sick, according to the Centers for Disease Control and Prevention. One is the raw eggs that many recipes call for. The other is the flour.

Raw eggs carry Salmonella, bacteria that can cause severe stomach upset and that every year kill 450 people in the U.S. Salmonella makes 1.2 million people sick every year.

But even egg-free dough isn’t safe if it contains raw flour, the CDC notes. Uncooked flour can carry a variety of disease-causing germs, including E. coli. An outbreak of E. coli traced to raw flour made 63 people sick in 2016.

So even if you’ve been eating raw cookie dough for years with no apparent ill effects, it’s time to stop, the CDC advises. Products made with cookie dough, such as ice cream, have heated the dough to kill germs.

“Do not taste or eat any raw dough or batter, whether for cookies, tortillas, pizza, biscuits, pancakes, or crafts made with raw flour, such as homemade play dough or holiday ornaments,” the CDC advises.

“Do not let children play with or eat raw dough, including dough for crafts.”

Handling food, including flour, requires care and hygiene.

“Keep raw foods such as flour or eggs separate from ready-to eat-foods. Because flour is a powder, it can spread easily,” the CDC notes. “Follow label directions to refrigerate products containing raw dough or eggs until they are cooked. Clean up thoroughly after handling flour, eggs, or raw dough.”