Microbiologist Uncovers Bacteria Levels on Leftover Pizza

A recent experiment has highlighted the alarming amount of bacteria that can proliferate on leftover takeaway pizza. Conducted by microbiologist Nicholas Aicher, the findings may cause consumers to reconsider their late-night meal choices. The experiment was shared on his popular TikTok account, @howdirtyis, which boasts nearly 500,000 followers and has drawn significant attention, amassing over 13,000 views.

In the video, Aicher analyzed a large half-cheese, half-pepperoni pizza shortly after purchase and again the following day. He began by swabbing samples from each side of the pizza and then repeated the process with leftover slices the next morning. The samples were transferred to petri dishes, which were incubated for an undisclosed duration before being checked for bacterial growth.

Upon inspection, Aicher noted that the sample from the fresh cheese slice appeared “spotless,” while the fresh pepperoni slice showed considerable bacterial growth. Surprisingly, the older cheese slice displayed some bacterial presence, described as “a lil bit of yuck.” In a twist, the day-old pepperoni slice had less bacteria than the fresh one, an outcome that Aicher found difficult to explain.

Nicholas Aicher commented on his experiment, stating, “I thought it would be fun for people to know all the little nastiness that we don’t think about every day.” Despite the unsettling results, many viewers remained unfazed by the findings. Comments included statements like, “I’m still eating it,” and discussions on the preservative nature of salt in pepperoni.

Aicher has previously tested the “five-second rule,” which posits that food dropped on the floor can be safely consumed if picked up within five seconds. In that experiment, which has received over a million views, he placed petri dishes on the floor for varying lengths of time, observing bacterial growth on each. His results indicated that food left on the floor, regardless of time, can still harbor significant bacteria.

The findings from both experiments underline the importance of food safety and hygiene, prompting a broader conversation about what consumers should consider when consuming takeaway meals. As scientists and health experts continue to explore foodborne bacteria, these experiments serve as a reminder of the unseen factors that can affect our health.