When I came across this article I was so intrigued about it just because it's something I've said several times before. I'm talking about the rule many of us have used, or at least said it at one point or another: 5-second rule.
Donald Schnaffner a Professor at Rutgers University who specializes in food science has decided to put the five second rule to the test. the research tested four differnt surfaces, stainless steel ceramic tile, wood and carpet with four different foods, watermelon, bread, bread and butter, and gummy candy. Four different contact times were 1 second, 5 seconds, 30 seconds, and 300 seconds. The bacteria that was used to inoculate the surfaces was Enterobacter areogenes, a nonpathogenic "cousin" of Salmonella naturally occurring in the human digestive system. The bacteria was inoculated in either tryptic soy broth or peptone buffer. Each of the surfaces was inoculated and allowed to completely dry before the samples were dropped onto them. The results showed that the watermelon had the most contamination and the gummy candy had the least. Simply put the more moisture a food contains the more bacteria the food will contain. This was found because bacteria move with moisture which allows moist food to have the higher risk of transfer. While it is also true that the longer the exposure on the floor the more risk of bacterial transfer, there were results that showed that transfer happened instantly.
Journal Reference:
Robyn C. Miranda, Donald W. Schaffner. Longer Contact Times Increase Cross-Contamination ofEnterobacter aerogenesfrom Surfaces to Food. Applied and Environmental Microbiology, 2016; AEM.01838-16 DOI: 10.1128/AEM.01838-16
This is fascinating. Growing up I always used the 5 second rule, but thankfully is was not food with a lot of moisture in it. But this study makes a lot of sense. Did the results differ any depending on what the bacteria was inoculated in of the two?
ReplyDeleteMeh...it builds your immune system ;)
ReplyDeleteSo different foods have various affinities to bind to the bacteria they tested, but did they consider if other bacteria would also have a different affinity to transfer? And anyway, if the bacteria they tested is naturally occuring in our digestive system then...I still don't care that that bacteria has a high affinity to transfer to my food when I drop it on the floor. ha!
ReplyDelete