CBS Local — You may want to rethink accepting a slice of cake after the birthday boy or girl blows out the candles.

A recent study, “Bacterial Transfer Associated with Blowing Out Candles on a Birthday Cake,” has found that blowing out birthday candles spreads tiny drops of saliva and tons of bacteria onto the cake.

Researchers compared the icing on two cakes — one where candles were blown out, and another where they were not. They found that the icing of the cake with blown-out candles had 1400 percent more bacteria than the icing on the cake that was left alone.

The researchers said in their paper they hoped the results “may help raise awareness of possible health risks associated with birthday celebrations and encourage others to take steps toward preventing the spread of bacteria.”

[H/T KDKA/CBS Pittsburgh]