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Does blowing out birthday cake candles spread germs? Experts say...

A study found that blowing out birthday candles greatly increases the amount of bacteria on the cake's frosting.
/ Source: TODAY

We may be entering the height of cold and flu season which means the tissues are flying, hand sanitizer is being squirted left and right, and everyone is trying their best to cover their mouths when they cough.

But when it comes to sharing food, we're not always so cautious. Let's face it, who can resist nabbing a that last bite of pie from a loved one's plate?

In addition to the usual holiday gatherings, plenty of people also celebrate birthdays, too. In May, the Journal of Food Research reported that blowing out candles on a birthday cake increases the amount of bacteria on frosting by 1400 percent. So with more germs floating around, does that mean you should avoid partaking in a birthday cake that's been blown on?

Homeless children blow out their birthday candles in Dallas.
Homeless children blow out their birthday candles in Dallas.Thisbe Grace Photography

While some cautious parents may panic and opt for cupcakes, or just do away with the tradition altogether, many medical professionals are saying to keep calm and blow on.

The level of bacteria that lands on the cake depends on the blower. In the study — in which scientists ate pizza to stimulate their salivary glands before blowing out candles on a frosted styrofoam cake — at least one blower increased bacteria levels by 120,000 percent. This may be the person for whom inventor Michael Tropeano filed a patent for a sanitary birthday cake cover and candle system in 2008.

Despite that alarming figure, it doesn’t look like Tropeano has made a dime on his yet-to-hit-the-shelves invention. And doctors aren’t overly concerned.

Dr. Marc Leavey, an internist at Mercy Personal Physicians in Lutherville, Maryland, told TODAY Food he can't recall the birthday candle conundrum ever coming up in more than 40 years of medical practice. He also asked his four children, parents of 10 grandchildren, for their opinions. “One of my daughters acknowledged that some mothers are nervous about this and solve the problem with cupcakes,” admitted Dr. Leavey.

“Two of my children dismissed the concept as ‘silly’.” Leavey says he questions the significance of the study’s findings.

“If you bought 14 tickets in the recent Power Ball craze that swept the country, you would have raised the likelihood of your winning the quarter-billion-dollar jackpot by 14 times,” notes Leavey. “But the probability remained that you would not have won. Fourteen times a clinically insignificant amount remains a clinically insignificant amount.”

Dr. Bobbi Pritt, head pathologist at Mayo Clinic, says she has never encountered someone getting sick from eating birthday cake, either. Pritt points to cell phones as being bigger culprits of spreading bacteria.

Still, it’s hard not to picture bacterial missiles flying in flecks of spit. We may not be able to see it, but we know oral bacteria is present. Why? Most of us wake up in the morning with bad breath. All of us rely on this bacteria to help digest our food.

“As a dentist and bacteriologist, I need to explain that the vast majority of bacteria, including oral bacteria, are actually good,” says Harold Katz DDS, founder of California Breath Clinics. Good oral bacteria help defend against infectious pathogens.

But, there is such a thing as bad oral bacteria. Katz cites Strep Pyogenes, which causes strep throat and ear infections, as being the most commonly passed oral bacteria. The CDC reports several million cases of strep a year in the U.S. and between 1,100 and 1,600 die from complications of strep. (For comparison, as many as 40,000 people died in the U.S. in car accidents in 2016, according to the National Safety Council.)

So eating blown-on birthday cake might not be so bad but what about sharing food?

"Eating cake where someone blew out the candles is about the same level of bacterial exposure as sharing food," Dr. Christopher Hollingsworth, endovascular surgeon at NYC Surgical Associates told TODAY. "But if you are using the same utensil, that would make it substantially more likely that you are exposing yourself to the same bacteria or viruses in their saliva."

However, if people aren't actively suffering from an illness, sharing food is relatively "low risk."

Not surprisingly, most doctors are more concerned with the sugar and calories in the cake than the potential for illness-causing bacteria on top. “Viewing the birthday candle bacteria issue through the lens of historical reality, this does not appear to be a significant vector for disease,” said Dr. Leavey, before adding that the majority of Americans are overweight which results in the bigger health crisis the U.S. is facing.

But even if this birthday candle bacteria isn’t a guaranteed sick warrant, one does have to wonder why the study involved a styrofoam cake and the frosting ended up under microscopes instead of in mouths.

It just seems like a missed opportunity to eat more cake ... all in the name of science, of course.