New book from Clemson professor busts the ‘five-second rule,’ dishes on the risks of double-dipping and buffets

Little girl with a face full of chocolate food

Germaphobes, this one’s for you. And maybe it should be for the rest of us heading to holiday dinners in the next few weeks.

A new book, “Did You Just Eat That?” from Clemson University food scientist Paul Dawson and co-authored by Brian Sheldon of North Carolina State University, gets real about how easily germs spread via human contact with food.

To sum it up: very easily, but there’s no need to full-on panic.

“The overall message is that we don’t want everyone to be germaphobes, but it’s good to be aware,” Dawson says.

Among other revelations, the book reveals the icky truth about the “five-second rule,” how germs are spread when someone blows the candles out on a birthday cake, and the faux pas of double dipping, and it removes all romantic notions about sharing a bucket of popcorn at the movies.

For starters, the “five-second rule” is a myth, Dawson says. If the food hits the floor, whatever micro-organism happens to be on that surface will immediately, without seconds of delay, attach itself to that tasty morsel you’ve decided is worth the risk of eating anyway. In other words, that germ will end up in your mouth.

The birthday candle scenario: As fun as the tradition is, just know that whoever the celebrant is will be blanketing the cake with germs. It’s not a mystery why after birthday parties, attendees may find themselves coming down with the common cold the birthday boy or girl may have been recovering from.

Double-dipping is commonly considered a party foul, but it still happens reflexively while people are chatting at parties and inadvertently put the same chip they just bit off of back in the artichoke dip for round two.

“I definitely don’t do it anymore,” Dawson says.

Popcorn at the movies and eating at a buffet or any large gathering where people are handling common utensils all have the potential for germ-sharing. But the good news is, most of us can and do handle it and won’t even know the dangers lurking because our immune systems are strong enough.

“We eat a lot and normally don’t have any problem,” Dawson says. “Numbers from the CDC [Centers for Disease Control and Prevention] seem high, but most people don’t have a problem.”

The bad news, however, is that sometimes the germs will strike. Dawson recalls a time when everyone at a family reunion became ill, and it was most likely the result of a foodborne illness. The elderly, very young, and those with suppressed immune systems are also much more susceptible to catching a cold, the flu, or any number of intestinal viruses that are often spread via contact with food.

And one thing to remember: Microbes, such as salmonella, can live on dry surfaces for weeks, Dawson discovered, so just because a surface doesn’t look dirty, doesn’t mean anything.

The last chapter of the book gives some survival tips: Always wash your hands and clean food-prep surfaces before use, without exception. And avoid cross-contamination between raw meats and fruits and vegetables that won’t be cooked.

As a professor in the food, nutrition, and packaging sciences department, much of Dawson’s academic career has been focused on providing answers to questions about common food safety practices. His research has garnered him widespread attention.

While his research spans far beyond gastronomic urban legends, Dawson has used projects to spark interest in the science behind food safety in both his students and the public. Many of his popular studies first took shape during brainstorming sessions in his Creative Inquiry course for which students conduct multisemester research projects. After a few scientific papers drew attention, he decided to put his research and findings on the topic together in one place.

“Did You Just Eat That?” is available on Amazon.


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