In a video experiment on TikTok that garnered more than 13,000 views, Nicholas Aicher, a senior quality control analyst in Chicago, compared bacterial growth on pizzas shortly after purchase and the following day.
Asher began the experiment by taking samples from a large pizza, half cheese and half pepperoni, using a cotton swab. He then transferred the samples to Petri dishes and placed them in an incubator overnight.
Upon examining the fresh samples, the cheese slice was found to be "perfectly clean," while the pepperoni slice appeared to have significant bacterial growth. Examination of the slices a day later revealed minimal bacterial growth on the cheese slice along with an "unpleasant odor," while the older pepperoni slice contained less bacteria than the fresh one, a finding he could not explain.
Despite the results, the experiment did not stop his followers from continuing to eat ready-made pizza, as one of them wrote: "I still eat it," and another commented: "The pepperoni is too salty, and bacteria don't like salt."
Aicher had previously tested the "five-second rule" to see if it was safe to eat food that had fallen on the floor if picked up within five seconds. In a previous video that garnered over a million views, he placed pieces of food on the floor for varying periods of time, then transferred each piece to a petri dish to observe bacterial growth.
The results showed that all samples contained bacterial growth, even food that had been on the ground for only one second. The five-second plate contained a similar amount of bacteria, contradicting the common belief that food becomes safe if picked up quickly. Samples left on the ground for 10, 20, and 30 seconds showed a gradual increase in bacteria, while the sample left on the ground for one minute contained a similar amount to the five-second plate.