A Rule Worth Keeping?

Student guest post by Jay Watson

We’ve all been there at some point before: a hot summer day, your delicious ice cream cone or tasty treat, and that uneven sidewalk. After taking about ten steps away from the vendor, you mistakenly put your foot into a gigantic fault in the sidewalk and accidentally toss your tasty treat face-down into the pavement. For many of us, “what now?” is actually a deliberation of a bunch of different, yet seemingly important questions: Who is watching me? How hungry am I? How much did it cost? Does this thing look dirty? Can I salvage most of it? But perhaps what unites us all more than any of these ponderings is the underlying question that our clumsiness has begged numerous times before: “Is this thing safe to eat?”

The answer to this question (much like our own consideration as to whether or not we actually pick up that double fudge delight now complete with grit and germ topping) is that ‘it depends.’ Though all of us are probably familiar with the 5-second rule from elementary school days, in actuality, only a few have tested its validity with science. The first person to inquire about the topic was a senior high school student who was working through an internship at the University of Illinois in 2003 [3]. In her experiment, Jillian Clarke dropped gummi bears and fudge-striped cookies onto tiles of E. coli (with pre-established organism counts) to see how many microbes would be transferred in 5 seconds or less. The results of her experiments showed that organisms can be transferred within 5 seconds [5]. In addition, she dispersed surveys and found that significant proportions of people (70% of women and 56% of men) she sampled were guilty of pick-it-up behavior [1]. In order to further test this myth, researchers at Clemson University (using Salmonella as their organism and bread and bologna as their test food) used similar methods to test surfaces including tile, wood flooring, and nylon carpet. Among their findings, they discovered that the survival times for some of the organisms on each of the surfaces were several hours, even days [5]. Like Clarke, they also noted that organisms are definitely transferred to food items within five seconds, with actual counts increasing with an increasing duration of time (for instance, there was a notable ten-fold increase in bacteria between five seconds and one minute) [4].

Granted, minimal research has been done in this area, but with consideration of the outcomes of these few inquiries, and perhaps with a little bit of common sense, we might best leave anything that lands on something other than our tongue for the birds or for the trash. However, I believe that there’s more to this matter than just how many germs or how fast they transfer. While many of us may have considered eating something off of the ground, it is less likely that we’ve considered eating it because it might be ‘dirty.’ Though it may sound like a ridiculous idea, perhaps there are more aspects to this issue than it would seem. While I’m certainly not promoting that we pick up garbage off the street and chow down, perhaps throwing out the 5-second rule wouldn’t be in our best interest.

Why? Maybe we need a little more dirt; a little less antibacterial hand cream. According to Wikipedia, the hygiene hypothesis states that “the lack of early childhood exposures to infectious agents, symbiotic microorganisms, and parasites has increased our susceptibility to allergic diseases by modulating immune system development” [2]. Simply put, our immune systems may have gone awry because we’ve eliminated many of the challenges for it. This has several implications today: are we ‘too’ clean? Have we developed environments that disrupt our child’s health? There are certainly others as well [6]. Many of these questions are definitely worth considering, but my point is that perhaps our immune systems need a little more in order to keep them in check. Now I would be the first to acknowledge that there are extenuating circumstances in all of this. After all, some floors (or any other germ-harboring surface for that matter) are dirtier than others; some materials are more absorbent and promote growth of organisms better, etc. Likewise, I’m not arguing that we should stop taking baths or eat our dinners off the floor. Common sense and a healthy lifestyle should by no means go by the wayside either. But next time, when you drop your lifesaver on the ground at work and run through that list of questions, you might consider whether or not “a little dirt don’t hurt.”

Works cited

[1] Clark, AS. 2006. Dry Floors Cleaner than Expected, but Existing Pathogens will Transfer. CBS News.

[2] Hygiene hypothesis. 2010. Wikipedia.

[3] Five-second rule. 2010. Wikipedia.

[4] Franko, M. Does the five second rule really work? 2010. HowStuffWorks, Inc.

[5] McGee, H. 2007. The Five-Second Rule Explored, or How Dirty is that Bologna? The New York Times.

[6] The Hygiene Hypothesis: Are Cleanlier lifestyles Causing More Allergies for Kids? 2007. Science Daily.

What is the Hygiene Hypothesis?

Guest post by Zainab Khan

In most western countries, germs have become synonymous with the idea of something bad that needs to be killed as quickly as possible. However, people have long been questioning the validity of these ideas; a few decades ago it was hypothesized that not enough exposure to germ can and does cause insufficient development of an individuals immune system. New studies have recently shown that this idea of getting rid of all germs, and keeping children exposure to them at an absolute minimum, may possibly cause more harm then good; over cleanliness is suspected to be one of the main reasons that there is such an increased number in asthma and allergy ridden people in western countries. Also, compared to just a generation or two ago, people today have an increased chance of having/developing allergies. Is this all due to society’s craze over germs?

It is important when talking about allergies to have some working knowledge on what happens when an individual has allergies or an allergic attack. Allergies are an extreme and inappropriate reaction by an individual’s immune system to what typically is a common harmless stimuli found in a normal environment; the body takes something such as hay, food, pollen, etc. and has a hypersensitivity reaction to it. The body ends up activating its white blood cells (these are the cells that defend the body against any foreign bad stimuli), which typically are what help humans ward of virus and bacteria, for example the flu or an infection, which results in an inflammatory response. This inflammatory response manifests itself in different ways: asthma, eczema, hives, runny nose or eyes, coughing etc.

The Hygiene Hypothesis

Over two decades ago, the idea that there is such a thing as too much cleanliness was first proposed by David P. Strachan in his Hygiene Hypothesis. The idea behind this theory is that a lack of early exposure to the types of germs and stimuli that people used to have is the cause of allergies. In developing nations and in earlier time periods families tended to be larger then today. It was uncommon to have just one or two children; the idea behind having more children is that the elder child exposes the younger children to more germs and in turn the children end up having to develop a stronger immune system because the immune system has been fully developed by all the early stimuli [1,2]. This idea of exposure to other children has also held true for children who attend daycare at an early age. Daycare children tend to develop fewer allergies then those who are never in such environments. Research has gone even farther to say that children who are exposed to hepatitis A or the measles are less likely to have certain types of allergies [3].

Arguments against the hygiene hypothesis emerged when statistics were followed about inter city African American children in the United States, who have very high numbers of asthma. A study was done that showed that many of these children had been sensitized to the common allergens found around them; however, they still developed asthma at the same rate as those kids who were not sensitized to the same allergens [4]. Also, it is a scientific fact that some allergies have a genetic component. A child who has two parents with allergies has a 75% chance of also developing allergies. There are genetic links that have been found between certain types of allergic responses which complicates the idea of how much immunity is inherited and how much can be developed [5].

Although the idea of germ exposure has been building momentum within the last few years, the debate and research behind it is certainly not complete. If the hygiene hypothesis is true, this opens up another type of debate on how much and what kinds of bacteria, exposure, and caution should be taken around children. What exactly are the “right” germs, and how many are too many? In a society obsessed with antibacterial hand soaps, disinfectants, and bottled water it is going to be quite a challenge trying to convince people that germs are not all that bad.

Works Cited

1. Am. J. Respir. Crit. Care Med., Volume 164, Number 7, October 2001. The Increase in Asthma Ca Be Ascribed to Cleanliness 1106-1107 Link.

2.Strachan David, Thorax. Family Size, Infection and Atopy: The first Decade of the ‘hygiene hypothesis’ Link.

3. Matricardi Paolo, Rosmini Franceso, Riondino Silvia, Fortini Michele, Ferrigno Luigina, Rapicetta Maria, Sergio Bonini, BMJ 2000;320 Exposure to foodborne and orofecal microbes versus airborne viruses in relation to atopy and allergic asthma: epidemiological study 412-417. Link

4. R. Call, T. Smith, E. Morris, M. Chapman, T. Platts-Mills, The Journal of Pediatrics, Volume 121, Issue 6 Risk factors for asthma in inner city children, 862-866. Link

5. Mackay, Rosen, Volume 344, January 2001. Allergy and Allergic Diseases 30-37
Link.