Speaking to Viral, Paula Teixeira, professor and researcher in the area of food safety at the Faculty of Biotechnology at the Universidade Catolica in Porto, adds that the belief that it is safe to eat any food that has fallen to the ground as long as it has been picked up in less than 5 seconds “is just a myth”.
“The 5-second rule is baseless. The microbes don't just wait there and only after 5 seconds do they attack or pass into the food”, she jokes. The food safety specialist clarifies, however, that there are some variables that can make “greater or lesser” the ability of microorganisms to adhere to food.
One of them is “the kind of food that falls on the floor”. “In a bread with jam, if the microorganisms are on the floor, they will adhere to the jam. If what falls is a cracker, which is very dry, they will have more difficulty in adhering”, she exemplifies.
On another level, microbial adhesion also varies according to surface roughness (microorganisms tend to adhere more easily to rough surfaces).
Finally, food “falls on a clean surface” or “falls on a dirty surface” is different. In the first case, the probability of being contaminated will be lower at the outset.
