Monday, May 17, 2010

Is Raw Cookie Dough Safe to Eat?

Posted by Kirk
On a Tuesday evening, our toddler quietly tucked into bed upstairs, my wife called to be from our study, "You know what would really make my day?"

I paused and considered my limited options before answering. I've been married long enough to know this is a trick question. What she was really saying was, "You know what I'd really like you to do for me?"

After careful consideration of my options I said that I was reluctant to answer but that my best guess was that she wanted a massage. "A close second," she answered. "I want a big bowl of cookie dough."

My first thought turned to eggs.

You see, I work with a lot of volunteers in my capacity as a naturalist. Earlier this month was Volunteer Appreciation Week so every day we had baked a fresh batch of cookies in gratitude. Naturally, the topic of eating raw cookie dough came up as we scooped round balls of gooey egg, flour and butter onto a baking sheet. It turns out a majority of the staff (myself included) enjoys eating the raw dough as much or even more than eating the baked cookies. Since we couldn't spend large amounts of time making cookies every day of the week while on the company dime we were using pre-made dough out of a tub. I pointed out the warning in red all capital letters on the lid. "DO NOT CONSUME RAW COOKIE DOUGH."

It turns out there was an e-coli outbreak related to uncooked premixed dough last July and the companies have beefed up their warnings. (It was still a tiny warning though.) While the outbreak last summer was e-coli, the normal concern with eating any product with raw eggs is salmonella.

My first thought turned to eggs because I've been thinking a lot about eggs lately what with it being spring. I've been eager to monitor our Eastern Phoebe nest at work but this year it has been a bit of a fiasco. The Phoebe laid three eggs and a brown-headed cowbird destroyed them all. She laid more and the cowbirds dumped their own eggs into the nest for her to incubate.

"You know," remarked a co-worker as we weighed the risks of eating the raw dough, "the salmonella is all on the outside of the eggs." I hadn't heard that and as I thought about it I realized I really didn't know much about salmonella in eggs. Being such a big fan of cookie dough I figured I had better do some investigating. My mother was a home economics teacher back in the 1970s and she had diligently taught her students to not consume raw eggs while at the same time teaching her toddler how to lick the raw egg filled batter from the electric beaters. I asked her some questions about raw eggs first and then sought out answers online.

It seems contamination on the outside of the egg is a thing of the past as new washing techniques have eliminated that problem. Not grinding your egg shells up and adding them to your cookies is still probably a good idea though. The real problem these days is salmonella in the inside of the egg. According to several sources, it seems that in the US, about 1 in every 20,000 eggs are internally contaminated with salmonella. That's a 0.005% rate of contamination. Given average American egg consumption you're likely to encounter a contaminated egg once every 84 years. Keep in mind cooking kills the bacteria so the odds of that one in 20,000 egg being in your raw cookie dough are very low. There are two eggs per batch usually so the odds are then one in 10,000 that each batch of dough will be infected. Interestingly though, it appears that rates of internal contamination with salmonella differ across the country. It is more prominent in the Northeastern US where, according to the CDC, the rate is one in 10,000 egg so I guess one in every 5000 batches of dough out east will have salmonella.

So in terms of the eggs sitting in my fridge right now, yeah, the odds are really low they have salmonella. If you are really worried about the odds, you can use pasturized eggs and that eliminates the problem completely. This weekend I threw caution to the wind and whipped up a fresh batch of dough with regular old eggs.

The dough is all gone now and not a single cookie was ever made. It tasted great.