Is the “Five-Second Rule” True?
The “five-second rule” that food dropped on the floor for less than 5 seconds is safe to eat is not always true. Contamination depends on factors like moisture levels, the number of germs on the floor, and the time the food spends in contact with the floor.
If you drop wet food on a dirty wet floor, it gets “contaminated” faster than if you drop dry food on a dry floor. There is some logic behind the “five-second rule;” it just isn’t true as an absolute statement.
Other factors include the amount of surface era that makes contact and one’s ability to wash the food.
- If you drop an apple on a clean floor, pick it up quickly and wash it under clean running water, then you should be okay.
- If you leave the apple on the floor for one minute, it will have more germs on it than it would in 5 seconds. Time does matter, that part is true.
- If you drop spaghetti on a dirty carpet, it doesn’t matter if you wait five milliseconds or five hours, germs will get on the food instantly. Sure, five hours will net you more germs, but your food will pick up dirt and microorganisms as soon as it hits the floor. That means food left on the floor for an instant can get contaminated if conditions are right.
TIP: “Germs” refers to bacteria and other microorganisms that can make you sick.
“The Five Second Rule”
Most of us have heard the old wives’ tale that food dropped on the floor remains uncontaminated if picked up in less than 5 seconds, but that is an oversimplification of the facts more than a helpful bit of advice.
There is no time limit for germs to be spread from one surface to another. This is true even in the best case scenarios when dry food is dropped on a clean, dry floor.
Instead, germs transfer on contact, as High-school student Jillian Clarke found in a 2003 study. (Students tend to discover interesting things, such as it was with the suspected fluid properties of glass).
Should You Eat it Anyway?
The five rule isn’t an absolute, but that does not necessarily mean that dropped food is too high-risk to eat.
There are variables. How scarce or high priority is the food? Is the food wet or dry? How contaminated is the surface? Can washing or cooking clean the food? How much risk are you willing to take?
People tend to minimize risk if food is scarce or highly desirable. A starving person is in danger from the lack of food as much as they are from the threat of contamination. Even people who are not hungry will prioritize certain foods. You may pick up a desirable food like candy or a cookie from a kitchen floor but leave boiled cauliflower.
Germs aren’t necessarily bad; we need some exposure to keep our immune systems strong. Still, one adage is true, and that is, “when in doubt, throw it out.”
Is the 5-Second Rule True?
Are Dry Surfaces Safer?
If the food and the surface it is dropped on is dry, it has a higher chance of avoiding a worrisome level of contamination.
Dropped food may not pick up any more germs than are safe to ingest unless your immune system is compromised. Common pathogens like Salmonella, Listeria, and E. Coli need moisture to survive according to WebMD.
However, wet food, damp floors or food exposed to surfaces containing virulent bacteria may contain unsafe levels of germs. The largest risk is from the germs on the surface. Hospital floors, for example, may contain dangerously high levels of contaminants as well as carry the possibility of exposure to dangerous pathogens.
So, if you drop the pudding in the hospital, use your common sense and forgo the five-second rule.
TIP: Germs can travel through food over time if it has the right consistency, so you have to worry about more than the contact surface itself.
FACT: Clemson University’s Department of Food, Nutrition, and Packaging Sciences conducted a study proving that large populations of Salmonella Typhimurium could survive for up to four weeks on dry surfaces and transfer to food at any time during that period.
Can you Kill Germs on Food by Washing or Cooking?
Washing fruit with clean, running water is important whether you intend to peel it or not. However, washing meat may disperse bacteria as water splashes. Washing any food, whether it has dropped on the floor or not, is not as effective for maintaining food safety as cooking it and storing it at the correct temperatures.
FACT: The cleanliness of your food depends on safe growing and storage conditions as well as contact with surfaces. Food can become contaminated even in a refrigerator if it is dirty or set to the wrong temperature. Some germs thrive in damp, cool refrigerators.
You Need to Eat a Peck of Dirt Before you Die
There is an old saying that You need to eat a peck of dirt before you die. The world is covered with microorganisms, and you are probably going to end up ingesting some number of them. They may even be good for you. You can’t live your life in a bubble and “no one can escape eating a certain amount of dirt on his or her food.”
The Benefits of Germs
An additional factor to consider is that children, and possibly adults, may be better off if they ingest bacteria than if they live in a totally clean environment. The folk wisdom of “eating a peck of dirt” isn’t just a matter of the inevitable; it may be good advice.
One scientific study found that children living on traditional farms where they were exposed to the animals directly and drank the milk from the farm, such as some Swiss children and some in Amish communities, had much lower incidences of asthma and grass-related allergies than those who did not. Other studies on immunology, such as that of Mary Ruebush, have linked exposure to pets and dirt in general to people having improved immune systems.
We need to consider our comfort level with dirt. Can we accept a certain amount of it in our surroundings or are we aiming for as sterile an environment as possible? Scientific articles may help you to understand what risks are acceptable to you, as ultimately. Facts aside, the five-second rule speaks first and foremost to individual decision.
We have many factors to consider when deciding whether to eat food that has landed on the floor. The risk of a picking up a dry cookie from your living room carpet may be minimal while picking up a watermelon slice from a hospital corridor might be unacceptably high.
TIP: Illness-causing germs can survive on many surfaces including your hands. Your best form of protection is to wash your hands well before touching food as well as keeping surfaces and kitchen tools clean.