With summer vacation approaching, you can’t help but to indulge in those ice cream cones, barbecued chicken wings and other summer’s unique food items. However, summer also means that you are more likely to apply the five-second rule to your dropped food that falls upon a dried up cement ground on a hot summers day. During other seasons of the year, who would even think about picking up dropped food off a wet ground or mud surface? This leaves us two critical question: 1) does the five-second food rule actually work and 2) if so, how well does this rule work when applied?
Admittedly I have used the five-second rule numerous times before and given that the rule did not result in a stomach flu most of the time, I would say that it works fairly well. Recent findings from a research carried out at Aston University suggest that the myth about the five-second rule – it is fine to eat food that dropped to the floor for five seconds or less – can be supported by scientific basis. The results indicated that by applying the five-second rule: foods picked up a few seconds after being dropped to the floor will contain less bacteria that if it is left there for longer time. Here, time is a vital factor that determines the amount of bacteria transferred from a floor surface onto a piece of food item. The infection risk carried by dropped food also depends on the type surface (wet vs. dry) and the type of bacteria presented on the surface at the time.
Image of dropped ice cream by Caro Wallis via Flickr
To decide on how well the five-second food rule actually work, we have to look at the number of microbes on our dropped ice cream after five seconds compared to one or three seconds. Jorge Parada, a medical director at Loyola University Health System said that “a dropped item is immediately contaminated and can’t be sanitized”. After five seconds, the dropped food may only picks up 1,000 bacteria but it may also pick up 10,000 bacteria – which is typically enough needed to get most people sick – depending on the situation. Therefore, infection risk really comes down to the type of food being dropped and the surface that it lands on. For example, you may apply the five-second rule to a cement ground but you probably do not want to use it if the food dropped in a toilet.
Below is a video by Vsauce, explaining the effectiveness of using the five-second rule. The video emphasized that time is the major factor.
[youtube]https://www.youtube.com/watch?v=rYXdsOEWBj0[/youtube]
Ultimately, the infection level depends on the person and his/her immune system. If a person have a strong immune system then the five-second rule may never fail them. But if you have a weak system then you may want to think twice about picking up dropped food – even if it’s just for one second. I guess the best advice is that: when in doubt, do not pick up the food.
-Blog post by Tien Vu
