5-second rule: to eat or not to eat. That is the question? – Part 1.

Image credit: Unsplash by Josephina Kolpachnikof

We all heard about the 5-second rule. Your mother always told you never to eat from the floor, but is it just an old wives’ tale? How long does it take germs to cross-contaminate food on the floor? cross-contamination can happen at different levels. Some are a higher risk than others. For example, when a piece of food falls on the floor versus food covered with a plastic barrier. So, if you drop a piece of say, bread, on the floor that is still in the plastic. The risk would be less than a piece of bread that is exposed to the floor.

According to researchers; Dawson, Cox, Black, and Simmons, the risk of bacteria to cross-contaminate food depends on the type of the non-food contact surface. Therefore, it’s important to sanitize non-food contact surfaces (wood, tile, carpets etc.) in order to prevent foodborne illness. Based on the article by Singh Bhullar, M., Monge-Brenes, A., Perry, B., Overdiep III, Nabwiire, L., Shaw, A., carpet is considered the least safe, but according to other research, carpet can also be safe. This is because bacteria are absorbed into the carpet and reduces the risk of cross-contamination in food. Moreover, the risk of cross-contamination is based on several factors: type of food (moisture level of food), type of surfaces, and exposure time. For example, cross-contamination will occur faster with lettuce (high moisture content) vs bread (lower moisture content).

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Lastly, both articles refute the 5-second rule, as cross-contamination of food occurs in less than one second. I’m not telling you to throw every food item that falls on the floor. For example, you would not eat food that falls on the bathroom floor versus the kitchen floor.

To drastically reduce foodborne illness, food items should be washed with water to remove the bacteria, and a plastic covering acting as a barrier around the food item helps reduce the contact with the floor. The most important thing we can do is sanitize non-food contact surfaces such as floors. This would prevent cross-contamination before it occurs and is critical step in preventing foodborne illness.

References

1. Dawson, P., Han, I., Cox, M., Black, C. and Simmons, L. (01 April 2007). Residence time and food contact time effects on transfer of Salmonella Typhimurium from tile, wood and carpet: testing the five‐second rule. Journal of Applied Microbiology, 102(4), pp.945-953. Website: https://academic.oup.com/jambio/article-abstract/102/4/945/6718586?redirectedFrom=fulltext
2. Singh Bhullar, M., Monge-Brenes, A., Perry, B., Overdiep III, Nabwiire, L., Shaw, A. (2021). Determining the potential food safety risks associated with dropped produce on floor surfaces in grocery stores. Journal of Food Protection, 84 (2), pp. 315–320. Website: https://www.sciencedirect.com/science/article/pii/S0362028X22054229?ref=pdf_download&fr=RR-2&rr=7e93101d5c531522
3. Scott, E., Bloomfield, S. F., Barlow, C. G. (1982). An investigation of microbial contamination in the home. Journal of Hygiene, 89(2), pp. 279-293. Website: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/9D95BF790D8422D828B5D3B563923B0E/S0022172400070819a.pdf/an-investigation-of-microbial-contamination-in-the-home.pdf