Author: Paul Dawson
Published: September 10, 2015
Dr. Paul L. Dawson, professor of Food Science at Clemson University, conducted research on how contact surfaces can contaminate food. He studied the underlying causes and bases for the “five-second rule”, the myth that shaped our beliefs on when food is safe to eat.
So is the five seconds on the floor the dangerous threshold that separates an edible morsel from a food poisoning case? As Dr. Dawson’s research suggests, it depends on how much bacteria transferred from the floor to the food in seconds and how dirty is the surface.
In 2007, Dr. Dawson’s laboratory at Clemson University published a study in—the only peer-reviewed journal on this topic—the Journal of Applied Microbiology. Researchers studied whether the time the food drops on a contaminated surface affects the transfer rate of bacteria. To examine, they inoculated squares of tile, carpet, and wood with Salmonella. After five minutes, they placed either bologna or bread on the surface for 5, 30, or 60 seconds, and counted the number of bacteria that transferred to them. They repeated the exact protocol after the bacteria stayed on the surface for 2, 4, 8, and 24 hours.
They established that the quantity of bacteria transferred to either food depended less on how long it touched or stayed on the contaminated surface. What mattered more, from their observation, was the bacterial count. In addition, it decreased over time after the first inoculation. Results suggest the issue is less determined by how long food languished on a surface but more on how infested with bacteria was it. Likewise, researchers learned surface material made a variance. Carpets, for instance, are better places to drop food than wood or tile.
Hence, when you consider eating spilled food, experts say, chances are in your favor you can consume that morsel and still be healthy. Although if in the rare chance you dropped it where several harmful microorganisms are present, no doubt they will transfer to the food you’ll consume.
Dr. Dawson’s research encourages us to keep our hands, utensils, and surfaces clean. The report was helpful although, from personal view, experts should conduct more research considering various factors. They should consider the health of the host, the variety of food dropped, and the surface material where it spilled.
- Morsel – a bite, mouthful, or small portion of food, candy, etc.
- Inoculate – to introduce a serum, vaccine, or antigenic substance into (the body of a person or animal), especially to produce or boost immunity to a specific disease.
- Virulent – highly infective, malignant, or deadly.