Image of Bacteria (p.c: https://www.youtube.com/watch?v=MzGYJAKfX1Y)
Q: If I've dropped something on the ground but I pick it up before 5-seconds, can I still eat it?
At least wash it first.
I should begin by saying, is it worth it? I can definitely tell you that all bets are off when it comes to carpets and streetside curbs.
I wish proper hygiene had gained more popularity than the notorious 5-second rule. If you aren't convinced, you might be after this study on the transfer of Salmonella Typhimurium. To boil it down for you, this data is conclusive evidence that when food comes into contact with any surface, bacteria is transferred immediately. The article describes, “Over 99% of bacterial cells were transferred from the tile to the bologna after 5 s of bologna exposure to tile.”
Your stomach has a pH of 2, which according to scale, it’s a strong acid that can dissolve a lot things, food and bacteria included. Following the 5-second rule is like not putting on a seatbelt or skipping sunscreen-- technically you’re not endangered, but you’re putting yourself at risk. It’s also just disgusting.
Jilian Clarke, a former student at the University of Illinois Urbana-Champaign, conducted an extensive 12-week experiment on the five second rule. Clarke's first test showed little transference of microbes from the campus grounds to the dropped food. She modified the experiment by introducing a control of sterile tiles, alongside the contaminated ones. In the first experiment, there were numerous factors that could have affected the results: floors could have been easily cleaned before the experiment was conducted, or the lack of moisture in the air may have dried out the more common types of bacteria found on the ground like E. Coli and salmonella. With the modifications, what she found was stunning. The professor supervising the study, Professor Meredith Agle, summarizes, “We did see a transfer of germs before five seconds. We were dealing with a large number of cells.”
The bottom line is that the five-second rule is a nauseating simplification of how environmental bacteria transfers to food, and there are many more factors than just how long food sits on a surface. Factors like the type of food, moisture, and chemicals involved are something you often neglect to take into consideration, but these things are difficult, if not impossible to gauge. And since you never know how "dirty" the ground really is...well, is that cookie you dropped worth the risk?