of baking cookies.

But it's a bad idea.

Because eating raw cookie dough really can make you sick,

and not just because it contains raw eggs.

In 2009, over 77 people

across 30 states got food poisoning

after eating prepackaged raw cookie dough.

Many experienced vomiting and bloody diarrhea,

and some had severe kidney damage.

In the end, Nestlé had to recall 3.6 million packages

of its refrigerated cookie dough.

And in 2016, another group got sick

after eating raw homemade cookie dough

made from General Mills products.

But despite what you'd expect,

the culprit wasn't salmonella in the eggs.

It was a shiga toxin-producing E. coli in the flour,

the same type that sometimes finds its way

into romaine lettuce and hamburger meat.

In fact, the CDC estimates it's responsible

for 265,000 illnesses,

3,600 hospitalizations,

and 30 deaths in the United States every year.

Now, normally E. coli likes to bunker down in moist places.

That's why scientists were surprised

when it turned up in flour.

And even today, it's a mystery

as to how the E. coli got there in the first place,

or how it survived in the flour's dry environment.

The problem is that the bacteria could have infiltrated

the flour during any step of the manufacturing process.

It might have snuck onto the wheat from animal poop,

or jumped to the flour from a contaminated

processing equipment.

There's really no way to know for sure.

Now, just to be clear, although flour was the culprit

in this case, raw eggs can still be just as dangerous.

In fact, the FDA estimates that every year

contaminated eggs cause 79,000 food-borne illnesses

and 30 deaths in the United States.

With that in mind, the CDC warns

against eating any raw cookie dough.

But, there's good news.

Although, yes, there's a risk your cookie dough

is contaminated, it's a pretty minimal one.

Many bakers, for example, taste test all the time,

no worse for wear.

Plus, a study found that over half of college students

ate unbaked cookie dough, and they lived to tell the tale.

Even better, the risk is lower today than ever before,

at least when it comes to store-bought varieties.

Because, after the 2009 outbreak,

companies like Nestlé and Pillsbury

have started including heat-treated flour

and pasteurized eggs in their dough.

By heating flour to 71 degrees Celsius,

you kill off any E. coli.

And the pasteurization process heats eggs just enough

to kill off bacteria without cooking the egg.

Heat-treated flour and pasteurized eggs

also explain why the sort of cookie dough

you find in ice cream is harmless.

But if you insist on making your chocolate chip cookies

from scratch, there's a DIY way to sterilize

your own ingredients: bake the cookie!

It'll still taste good.