On Tuesday, Sept. 25, Drury’s Safety and Security Office sent out an email stating that it was discovered that fruit flies had gained access to a petri dish containing salmonella samples in the Trustee Science Center. The email advised students not to have any open food or drinks in the building for the next seven days.

Marianne Crocker, a microbiology instructor at Drury, explained in greater detail what happened, giving more insight into the possible risk to students in the building.

(Photo via pixabay.com)

The facts

Crocker gave her students an experiment to identify certain things about an unknown bacterium. The class had been prepping for the assignment for several weeks and was just beginning to start their lab reports when a student approached Crocker and told her that their dish had been contaminated.

Crocker said, “We were at the point of finding out the metabolic reactions when the plates were all contaminated. Somebody brought up a plate with a crawling, fruit fly maggot. We had a number of plates that had maggots.”

Air is required to grow bacteria, meaning that the lids of the dishes may not have been fully secured.

“Fruit flies are very small,” said Crocker, “and the fact that you have to have [the dish’s lid] loose for air to come in for the bacteria and that there are fruit flies in the building, they can get in there.”

Fortunately, the bacteria Crocker was having her students identify was not extremely hazardous.

According to Crocker, the dishes contained “Enterobacteriaceae bacteria which includes salmonella, which includes shigella, which includes e-coli.”

“They were none of the species that would cause you to get deathly ill, but they were all of the species that if you ingested them, you would become mildly ill,” said Crocker.

Taking precautions

The email sent out by the Safety and Security Office was not meant to scare students. It was written with student safety in mind. Despite the potential bacterial spread being quite low, Crocker felt that it would be best to let students know.

After Crocker discovered the fruit flies, she immediately informed administration. Soon after, Drury Building and Grounds personnel wiped down all of the surfaces in the Trustee Science Center, and Crocker personally made sure the flies were dealt with.

Crocker stated she “decontaminated the lab” and has not “grown anything in the lab this week to kind of give it a chance for any residual flies that may be hanging around to be done.”

To prevent things like this from happening in the future, students will be taping their petri dishes shut. Crocker said that this will allow air in, but keep the fruit flies out.

At this time, the building has been disinfected and is considered clean. It is safe to have open food and drinks inside.

Written by Afton Jagels.