Overview

Some people quickly pick up and eat food that falls on the ground—if it looks clean enough—while others won’t even consider touching it again. There’s a popular belief that eatables are safe to eat if picked up within seconds of falling. The most well-known version of this belief is the five-second rule, which suggests that food dropped on the floor is still edible if retrieved within five seconds.

Microbiologist Puts the Rule to the Test

Nicholas Aicher, a microbiologist from Chicago, set out to investigate the truth behind this idea. He regularly shares videos on TikTok showing bacterial presence in public places, including movie theatres, by collecting samples. Responding to requests from his followers, Nicholas decided to test the five-second rule.

He conducted the experiment using petri dishes—standard tools for microbiologists to observe microorganisms. He collected samples from various surfaces and at different time intervals. The objective was to observe bacterial growth from food dropped and picked up between zero seconds to one minute.

Findings of the Five-Second Rule

Nicholas found that bacteria were present on food regardless of how quickly it was picked up from the floor. He confirmed that even a very short contact time is enough for bacteria to transfer to the food. The longer the food stays on the ground, the greater the bacterial contamination. Additional experiments showed that the higher the moisture content of the food, the easier it is for bacteria to attach to it.

Source: Mathrubhumi