Contract Manufacturing

The 5 Second Rule – Myth or Fact?

Rutgers University Researchers, Robyn Miranda and Donald Schaffner examined the effect of time during bacterial transfer from one of four different surfaces: stainless steel, tile, wood, or carpet. Each surface was coated with the same amount of bacteria and allowed to dry before food was exposed to the surface for 1, 5, 30, or 300 seconds. If the five-second rule held up, the scientists expected to see less bacteria transferred during 1 and 5 second exposures than in 30 or 300 second exposures.

As one might expect, different foods picked up different bacterial loads. The foods tested included watermelon, plain bread, buttered bread, and Haribo-brand gummy candy. No matter the exposure time, watermelon picked up the most bacteria, which was measured by plating homogenized food samples for CFUs. Bacterial transfer seemed related to food moisture, so the wetter a dropped food is, the more bacteria stick to it.

Paul Dawson, a professor in Clemson University’s Department of Food, and a team of Clemson researchers found that Salmonella typhimurium “can be transferred to the foods tested almost immediately on contact” and that the bacteria can survive for up to four weeks on dry surfaces in high-enough populations to be transferred to foods.

A 2003 study by then high-school senior Jillian Clarke, during an internship at the University of Illinois at Urbana–Champaign, likewise found that bacteria transfers to food immediately on contact. In her experiment E. coli moved from floor tiles to cookies and gummy bears well within five seconds.


A Contradiction

A UK study is contradicting the conventional wisdom that the five-second rule is mostly bunk.  They are claiming the amount of time food is on the ground really does have an effect on how much bacteria gets on the dropped item. Aston University’s School of Life and Health Sciences in England recently reported that the type of surface on which the food has been dropped has an effect, with bacteria least likely to transfer from carpeted surfaces. Bacteria is much more likely to linger if moist foods make contact for more than five seconds with wood laminate or tiled surfaces.

Food picked up just a few seconds after being dropped is less likely to contain bacteria than if it is left for longer periods of time, according to new research.   Moist foods left longer than 30 seconds, however, contained up to 10 times more bacteria than food picked up after three seconds. Dry foods dropped on the carpet experienced the slowest rate of bacterial migration.


Many Factors should affect your decision on whether to eat that fallen food:

1) What bacteria-virus-parasite spores-pathogenic fungus spores may be on the surface?. (A vast unknown).

2) What is the concentration of organisms particularly at the points of contact?

3) Moistness or texture of the material dropped influencing deformation and contact area of the material to the surface.

4) Does retrieval involve scraping it off the surface, or a straight and simple lif?

5) How long has the microbial life been present on the surface? ( Dried out, active and recent, old spores etc).

6) If it were less time would it be less contamination? ( Suggesting it may be the initial drop contact that applies the contamination).


The take-home message is that bacteria, including potential pathogens, can transfer to food in less than one second.


Sources:, Philip Perry ;and, Daniel Politi

Lesley AsendorfThe 5 Second Rule – Myth or Fact?

Probiotics and Prebiotics: What’s The Difference?

Probiotics are live beneficial bacteria and yeast and Prebiotics are food for these bacteria. Both prebiotics and probiotics are important for human health. Eating balanced amounts of both pro- and prebiotics can help ensure that you have the right balance of these bacteria, which should improve your health.


Probiotics: These are live bacteria and yeast found in certain foods or supplements that can provide numerous health benefits.

1) The good bacteria in your digestive tract help protect you from harmful bacteria and fungi.

2) They send signals to your immune system and help regulate inflammation.

3) Some of your gut bacteria form vitamin K and short-chain fatty acids.

4) Short-chain fatty acids are the main nutrient source of the cells lining the colon, promoting a strong gut barrier to keep out harmful substances, viruses and bacteria, and may reduce the risk of cancer.

The following probiotic foods naturally contain helpful bacteria:

1) yogurt

2) fermented foods including: Sauerkraut,  Kimchi, miso (fermented soy) Kombucha tea, Kefir (dairy and non-dairy). Some types of pickles (non-pasteurized).Other pickled vegetables (non-pasteurized).


Prebiotics: These are carbohydrates (mostly fiber) that humans can’t digest.

The beneficial bacteria in your gut eat this fiber. Foods that are high in prebiotic fiber include:  Legumes, the skin of Apples, Wheat bran, Barley, Beans, Peas, Oats,  Bananas,  Berries, Dandelion greens, Garlic, Leeks, Onions, Asparagus.

Prebiotic fiber goes through the small intestine undigested and is fermented when it reaches the large colon.  Some of those foods can also be considered symbiotic, because they contain both beneficial bacteria and a prebiotic source of fiber for the bacteria to feed on.  One example of a symbiotic food is sauerkraut.


Benefits: Research on the effects of probiotics is inconclusive, but it suggests that they may be beneficial in the following areas:


Digestive health: Numerous studies have found that probiotics may improve digestive health in some people.Taking probiotics while using antibiotics reduced the risk of antibiotic-related diarrhea by 60 percent.  24 trials found that probiotics could help prevent the life-threatening disease necrotizing enterocolitis in preterm infants.


Mental health: A smaller body of research suggests that probiotics may improve mental health.  Probiotics may alleviate the symptoms of depression, but the authors note that additional studies are necessary to confirm this. It is possible that probiotics have this effect because there is a link between gut and brain health.


General health: Probiotics may decrease:

  • The need for antibiotics
  • School absences from colds
  • The incidence of ventilator-assisted pneumonia
  • Gestational diabetes
  • Vaginal infections, such as yeast infections
  • Eczema


However, the review did not find high-quality evidence that probiotics can prevent illness, and the authors conclude that more trials are necessary.


A  word of caution about side effects:  According to the same review above, people with Crohn’s disease had a higher risk of adverse events when they took a specific probiotic.  People with weakened immune systems were also more vulnerable to side effects.  A 2018 analysis of probiotic trials warns that many studies do not report safety data, including information on adverse events, even when they claim to prove that probiotics work.


There is less research on prebiotics than on probiotics. As a result, the extent to which prebiotics improve health is unclear. Scientists are not yet entirely sure that they can strengthen the purported benefits of probiotics.



Update 6/15/20:

Lesley AsendorfProbiotics and Prebiotics: What’s The Difference?

There’s Good Fat and Bad Fat / Brown Fat vs. White Fat

The human body contains more than one type of fat. White fat stores extra energy. Too much white fat, a characteristic of obesity, increases the risk of type 2 diabetes, high blood pressure, and other diseases.

A less common type of fat, called brown fat, breaks down blood sugar and fat molecules to create heat and help maintain body temperature. Brown adipocytes (fat cells) , are prevalent in children as “baby fat,” but much less so in adults.

Around 36% of adults in the U.S. carry too much fat in their bodies and are now considered overweight or obese. Researchers have been looking for ways to activate the body’s brown fat. This could provide a way to fight the negative effects of weight gain. Long exposure to cold temperatures has been shown to boost brown fat activity, but simply exposing people to cold temperatures may not be a practical approach for most people.

Brown fat tissue does offers a glimmer of hope for burning off extra calories, and certain foods, such as coffee, turmeric, thyme, hot pepper and others are thought to activate or increase brown fat tissue.

Research :

Research, using mice, conducted at the Univ. of Pennsylvania, found that deleting or suppressing a particular gene that keeps the “browning programing” turned off, makes the white fat cells visibly be more like brown fat cells with more of the fat burning mitochondria which supply chemical energy to cells and create heat.  A 2012 study found injecting the hormone “irisin” in mice prevented the mice from becoming obese in spite of a high -fat, high calorie diet.

In a small study, a team recruited 14 women, aged 18-40, of diverse ethnicities. The participants took 100 mg of mirabegron every day, for four weeks;  that’s twice the FDA-approved dose to treat overactive bladder.

Results appeared on January 21, 2020, in the Journal of Clinical Investigation.

After four weeks of treatment, the women’s metabolism at rest was almost 6% higher, although their weight or the ratio of fat to muscle—hadn’t changed. Brown fat activity, as measured by PET/CT, had increased during the study, with the largest changes to women who had less brown fat activity to begin with.

These are just two examples of research into how to activate the “browning program,” to make white fat cells act more like brown fat cells.



National Institutes of Health, Research Matters report, Feb 4th   2020


Lesley AsendorfThere’s Good Fat and Bad Fat / Brown Fat vs. White Fat