Cultures taken from Halloween masks show bacteria that grew in 24 hours

Many Halloween costumes aren’t complete until a person dons a mask. But whether you bought your mask weeks ago or plan on a last minute purchase, have you ever wondered how many other people tried on the mask before you?

ABC 17 News purchased three masks from costume stores in Columbia: a plastic skull mask, a rubber wolf mask and a rubber devil mask.

We took the masks to Dr. Bethany Stone, a biologist with the University of Missouri, to swab the masks and find out what’s left behind after people try them on.

And what we found inside could be more frightening than what’s outside.

On Tuesday morning, Dr. Stone swabbed around the mouth area, the eyes, nose and outside of each mask.

“We will include or store these plates at 37 degrees Celsius, or 98.7 degrees Fahrenheit, so body temperature,” Stone said. “So the odds are that the bacteria we are growing could grow on a human body.”

Once the cultures were collected, Dr. Stone put them in an incubator for 24 hours.

On Wednesday morning, hundreds of bacteria colonies were found.

“Bacteria grew from almost every part of the mask,” said Stone. “Each colony, each little spot on these petri dishes is one bacteria cell that has gone on to divide and become multiple cells, enough for us to be able to see with the naked eye.”

The rubber devil mask had the most growth.

“The devil mask was especially contaminated, if you will, around the mouth,” Stone said. “So we have 500 or so colonies as an estimate there. I was surprised when I opened up that incubator this morning and saw this many colonies.”

The wolf mask registered the second-most bacteria, centered mainly around the mouth area.

The plastic skull mask had the least amount of bacteria growth, but most of the bacteria was also seen from the mouth.

Despite the large amount of growth, Stone said most of these bacteria are harmless. But there is still a little concern.

“The only thing at this point I would be concerned by is if a child, for example, has an open sore, maybe a cut on the face, that would be an opening where the bacteria might be able to get in and cause problems, cause a staph infection.”

Stone said if parents are concerned, the best way to get rid of the germs is to wipe down the mask with rubbing alcohol or hand sanitizer, focusing especially on the mouth, nose and eyes.

She said it would require further testing to determine if any of the bacteria found on the masks were disease-causing pathogens.