School Science Experiment Goes Wrong When Sara Lee Bread Won’t Grow Mold
The bread should've been covered in mold.
Published March 20 2025, 12:04 p.m. ET
A science experiment produced some surprising results in one elementary school classroom, where a teacher discovered that the bread she was using to conduct an experiment wasn't giving her the results she was expecting.
The educator shared what happened with her followers in a post that quickly went viral, raising some important questions about the ingredients we're consuming when we eat processed foods.
Keep reading to see how a casual investigation into how long it takes for certain germs to start growing on food turned into a question about the preservatives used in commercial baked goods after a loaf of Sara Lee bead failed to start growing mold.
Slices of Sara Lee bread aren't molding in classroom experiment.
One TikToker was surprised to learn that the bread she was using in an experiment wasn't breaking down as quickly as she expected it to. Elementary school teacher jordynharriskibbe posted about the experiment — which involved handling multiple pieces of bread with varying dirt and germs on your hands before sealing them in bags to watch mold grow — sharing how the Oct. 3, 2024 wasn't progressing.
In fact, as of Feb. 28, 2025, the educator said that none of the slices of Sara Lee bread had begun to show any signs of growth, which was something she believed had to do with the preservatives used in the bread.
"Sara Lee," she captioned the clip. "This turned into a whole different experiment."
The teacher wasn't the only one freaked out by the results of the experiment, and plenty of people hopped into the comments to share their disgust and concern.
"Three years ago bread wouldn’t last more than a week and now I’ve noticed our bread will be 'good' for over a month," one person wrote.
Another said that the results of this experiment were more frightening than the results the teacher was going for, writing, "This is scarier than seeing mold."
What is the "bread experiment?"
According to the C.S. Mott Children's Hospital blog, the purpose of this experiment is to show kids how many invisible germs are on your hands. Typically, you can do this project at home or in the classroom by taking at least three different slices of bread, and handling each one with hands that have increasing levels of germs on them.
The first would be the control piece, which shouldn't be touched by bare hands at all.
The second would be handled by someone who hasn't washed their hands, and the third would be touched all over by someone with clean hands. Then, each piece of bread gets put into a clear baggie and labeled so that the kids can watch to see which one begins to show the signs of mold and bacteria growth first.
According to the blog, the first mold spots should appear within a few days of starting the experiment, which obviously wasn't the case for the OP.
This appeared to raise plenty of questions about just how many preservatives are used in baked goods like commercially produced bread, and what happens once that bread is ingested.
While the OP's experiment didn't come up with those answers, it's clear that it did give the teacher, her students, and all of her followers on TikTok plenty to think about in the meantime.