Five-Second Myth Of Fallen Food, Disproved By Scientists

Are you one of those people guilty of the "5-second rule" on dropped food? A group of scientists from Rutgers University took the myth seriously to finally put an end to the long argued urban pop culture myth regarding the food safety of fallen food.

In a report on Science Daily, the research concluded that fallen food, as soon as it touches the ground, posts serious food safety hazard even it only lasted less than five second in contact with the floor. Food scientist Donald Schaffner of the research said that contamination begins in less than an hour or rather as soon as the food made contact with the floor.

The experiment was done using 4 types of surfaces­­-stainless steel, ceramic, wood and carpet and 4 types of different food sample--- watermelon, bread, bread and butter, and gummy candy. They also accounted four different contact time, less than a second, 5, 30, 300 seconds. They tested the intensity of food contamination by measuring the growth of Enterobacter aerogenes, nonpathogenic coliform bacteria, which is an indicator of fecal contamination, grown in tryptic soy broth and peptone buffer. It yielded 128 setups with 20 replicates each.

The results concluded that food cross contamination is higher when water is present in the food sample, as expected with the high bacterial loads detected in watermelon and low in the gummy candy. The researchers explained that water helps the bacterial cells to adhere in the food surface. Also as theoretically expected, the longer the time of contact, the greater bacterial load is expected. The carpet also yielded the least bacterial transfer.

Although bacterial cross contamination in food through direct contact is greatly influenced by many factors, the researchers emphasized that the "oversimplification" of the 5-second rule posts a great risk in food safety.  The research proved that bacteria can be transferred instantly upon contact to food contrary to what was believed in the myth. Though five seconds is relatively a short time to transfer higher loads of bacteria, the risk of acquiring a potential highly pathogenic bacteria or even other pathogenic agents like fungi and viruses is still a possibility that should not be overlooked.

The research was originally published in the American Society of Microbiology's Journal on Applied and Environmental Microbiology.