The 5 second rule of bacteria debunked
by Dr. Alan Kadish NMD
Somehow the urban legend came about to claim that if food was not on the floor or other surfaces for more than 5 seconds, other than your plate mind you, it was ok to eat. Should have been seen as a myth long ago.
Well lo and behold the researchers at Rutger’s University put the myth to the test and guess what…..it’s a myth. There is no clean rule of 5 or however many seconds for surfaces. Like all things in nature the contact is so dependent on moisture that there can never be a hard and fast rule. With that said let’s take some real life issues that you should know about. The study tried 2560 examples of what happens when food is on various surfaces.
You go to the local restaurant and sit down for a meal. The wait person comes by and “cleans” the table with the same old wet (hint:keyword is moisture) cloth and moves on. Your food falls off the plate and you grab in time to put into your mouth….YECH. The wet table coupled with the cleaning of the surface with a dirty rag, make the food retrival an absolute no-no…..it’s turned into a chemistry experiment. Let the table dry before allowing the waitperson to put clean napkins or more ridiculously, your clean silverware on the surface. Or better yet ask that they be places on the napkin until used.
Have kids ? Keep their hands and arms off the table and avoid having them eat food, from the table surfaces. It’s probably worth considering doing the microfiber wash the surface or do some disinfecting sprays because of the high bacterial load. Oh and for those with youngsters crawling on the floor…..
Overall food is cheap, your health is not. Pass on food products that have gone onto other surfaces vs your plate. Not all bacteria are your friends.
Questions or comments ? Call us at the Center of Health 541.773.3191
Rutgers researchers debunk ‘five-second rule’: Eating food off the floor isn’t safe
Rutgers Biomedical and Health Sciences News, 09/10/2016
Sometimes bacteria can transfer in less than a second.
Rutgers researchers have disproven the widely accepted notion that it’s okay to scoop up food and eat it within a “safe” five–second window. Donald Schaffner, professor and extension specialist in food science, found that moisture, type of surface and contact time all contribute to cross–contamination. In some instances, the transfer begins in less than one second. Their findings appeared online in the journal Applied and Environmental Microbiology.
The researchers tested four surfaces – stainless steel, ceramic tile, wood and carpet – and four different foods (watermelon, bread, bread and butter, and gummy candy). They also looked at four different contact times – less than one second, five, 30 and 300 seconds. They used two media – tryptic soy broth or peptone buffer – to grow Enterobacter aerogenes, a nonpathogenic “cousin” of Salmonella naturally occurring in the human digestive system.
Transfer scenarios were evaluated for each surface type, food type, contact time and bacterial prep; surfaces were inoculated with bacteria and allowed to completely dry before food samples were dropped and left to remain for specified periods. All totaled 128 scenarios were replicated 20 times each, yielding 2,560 measurements. Post–transfer surface and food samples were analyzed for contamination. Not surprisingly, watermelon had the most contamination, gummy candy the least.
“Transfer of bacteria from surfaces to food appears to be affected most by moisture,” Schaffner said. “Bacteria don’t have legs, they move with the moisture, and the wetter the food, the higher the risk of transfer. Also, longer food contact times usually result in the transfer of more bacteria from each surface to food.” Perhaps unexpectedly, carpet has very low transfer rates compared with those of tile and stainless steel, whereas transfer from wood is more variable. So while the researchers demonstrate that the five–second rule is “real” in the sense that longer contact time results in more bacterial transfer, it also shows other factors, including the nature of the food and the surface it falls on, are of equal or greater importance. “The five–second rule is a significant oversimplification of what actually happens when bacteria transfer from a surface to food,” Schaffner said. “Bacteria can contaminate instantaneously.”
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