Quickly raised should be considered fallen

The five-second rule still doesn't work

marks, Geektimes

The saying "Quickly raised is not considered to have fallen" in one form or another is known to everyone. We are talking about the so-called "five-second rule". Some people believe that if a product falls to the floor, then if it is picked up within five seconds, this product remains usable. It is claimed that harmful microorganisms simply do not have time to move to food.

In 2003, Gillian Clark, an intern at the University of Illinois, decided to check whether this was true or not. Under the supervision of her supervisor, Clark conducted a fairly large-scale scientific study. The intern took samples from the floors on campus. A laboratory, a dormitory, and cafeterias were examined.

After the obtained samples were examined under a microscope, it turned out that there were simply no significant amounts of bacteria in the source material. Therefore, it was concluded that a dry and relatively clean floor is an insignificant source of harmful bacteria.

Clarke conducted the second part of the experiment, placing the culture of E. coli on smooth and rough tiles for flooring. Pieces of food were placed on the same samples. After studying food samples, it turned out that E. coli was present in significant quantities on all of them. In other words, Clarke showed that the "five-second rule" doesn't work. Time did not play a special role – bacteria in an amount sufficient for human disease appeared on food within a second or two after the fall.

Interestingly, during her research, the intern also conducted a survey, the results of which showed that 70% of women and 56% of men know about the "rule". Many respondents have been guided by this rule almost all their lives when deciding how to deal with food that has fallen on the floor.

(Clark's work in 2004 was awarded Nobel Prize in Healthcare – VM.)

A little later, a number of experiments within the framework of the work on the "rule of five seconds" were conducted by the "Destroyers of Legends". The results of these experiments confirmed the results obtained by Clarke.

All this, of course, is interesting, but the problem with the experiments mentioned above is that they were conducted not by professional scientists, but by amateurs.

Now scientists from Rutgers University have decided to take up the matter. Rutgers University is a US state research university, the largest higher education institution in the state of New Jersey. The head of the study was Donald Schaffner, professor, nutrition specialist. The results have already been published in the authoritative publication Applied and Environmental Microbiology (Miranda and Schaffner, Longer Contact Times Increase Cross-Contamination of Enterobacter aerogenes from Surfaces to Food).

"The popular statement called the 'Five–Second Rule', which says that a product quickly picked up from the floor is not harmful to health, does not correspond to the real state of things," Schaffner said in a Rutgers Researchers Debunk 'Five-Second Rule': Eating Food off the Floor Isn't Safe. The scientist says that he and his team decided to take a serious approach to solving this issue, not considering the problem far-fetched or stupid. "We decided to use a serious scientific arsenal," says the head of the study.

In the course of their work, the scientists tested four types of surfaces, including stainless steel, ceramic coating, wood and carpets. Products such as watermelon, bread, butter sandwich, chewing candy were alternately placed on these surfaces. These products were left on the surface for different times. These are 1, 5, 30 and 300 seconds. Before putting the product on any of the surfaces, specialists placed a culture of Enterobacter aerogenes bacteria on such a surface. It is a close relative of Salmonella. Before placing the product, the scientists waited for the tested surface to dry. In total, 128 situations were tested with the "fall" of a particular product on a certain surface. Each situation was checked 20 times. The total number of measurements carried out by scientists is 2560.

As it turned out, most of the bacteria after the "fall" was on a piece of watermelon. Chewing candy received the lowest level of infection with the bacterium. However, no one chewed the candy itself, it was put on the surface in its original form, without a wrapper. "The transition of bacteria from surface to surface is fastest in a humid environment," says Schaffner. "Bacteria don't have legs, but they can move through the liquid. And the products with a high water content get the most bacteria... Of course, the most bacteria end up on the samples that have lain on the infected surface the longest."

An interesting result was shown by the food contamination test on the carpet. As it turned out, the carpet is the safest of all the surface types presented, despite our attitude to carpets. "The structure of the surface and the food plays an important role in the process of the transition of bacteria from one surface to another," says Schaffner.

In general, the study showed that the "five-second rule" does not work in most cases. Some types of surfaces and products turn out to be unfavorable for the transfer of bacteria when the product falls. But 5 seconds has nothing to do with it.

The "five–second rule" is a significant simplification of what actually happens when bacteria move from the surface to food. Bacteria can contaminate food almost instantly," the study participants said.

I think if an ice cream or a sandwich with butter fell on the floor (butter down, as usual), then there is nothing to be done here – it is undesirable to pick up all this if you do not want to get infected with E. coli or other bacteria. Sticky and wet foods are something that should not be picked up. But something like cookies, ordinary bread, dry sausage, etc. can be selected. But again, not all types of surfaces are safe. Picking up fallen food is like a lottery. You never know if you're going to get sick or if everything will work out. The prize is doubtful, of course.

Portal "Eternal youth" http://vechnayamolodost.ru  12.09.2016