ShoeZap® Science & Research

Thank you for your interest in the science supporting the effectiveness of the ShoeZap® UltraViolet Shoe Sanitizer.

Ultraviolet germicidal irradiation (UVGI) is the use of UV energy to kill or inactivate viral, bacterial, and fungal species. UVC wavelength light has proven a safe and effective method to sanitize air in hospitals, kill germs in drinking water, disinfect food preparation surfaces, and in other commercial and household applications for many decades. Proof of its effectiveness from both government (i.e. EPA, CDC, FDA) and private sources is long-standing, plentiful and indisputable.

This same technology is now available in a device that fits inside footwear to kill fungus, bacteria and other pathogens that thrive there. Proof of the effectiveness of this method of use is now also well documented from multiple private sources – mainly the makers of similar shoe appliances.

Ultraviolet C light is defined as that in a wavelength between 200 and 280 nm, with peak germicidal effectiveness in the 250-270 nm range (Sharp, 1937). It is known to penetrate cell walls, damage the genetic material in the nucleus of cells or nucleic acids in viruses, rendering them unable to replicate, ultimately resulting in cell death.

This brief summary is intended as a general overview. Summaries of usage, studies, expert opinion and other scientific content is so abundant as to be impractical to reproduce on paper. Instead, a detailed overview can (or will soon) be found on our website, www.pedifix.com

You’ll find 3 Categories of Supporting Research

1. UVC light effect on fungus, bacteria and other pathogens in general

   UVC light has been used to sanitize air in hospitals, kill germs in water supplies, disinfect and decontaminate food preparation surfaces and other commercial applications for decades, worldwide. The technology was discovered to disinfect water in 1877. In 1903 Danish physician Neils Finsen was awarded the Nobel Prize in Medicine for his research using UV radiation for the treatment of various diseases, including smallpox and lupus. During the 1930s and 40s scientists used UVGI light to control the spread of other contagious diseases. In the decades to follow, UVC light grew in popularity worldwide.

2. UVC light effect on fungus, bacteria and other pathogens inside footwear

   Studies sponsored by PediFix confirm those from other UV Shoe Sanitizer makers – UVC light kills pathogens that live and thrive inside footwear. Experiments conducted by the independent testing firm MicroCare of Shelton, Ct. and others performed by EMSL Analytical of Houston, Tx. both confirmed that the ShoeZap-type device does indeed kill the most common podiatric dermatophytes -- T. rubrum and T. mentagrophytes, inside shoes, even faster than the 5 minute first measurement timeframe chosen for the first study, summarized below. These specific microbes are believed to cause the majority of Athlete’s Foot and nail fungus infections (onychomycosis) in the United States.

   Below find a summary of our test results.

   “For your test we used the same two mold species used in the similar test report you sent us for reference (T. rubrum & T. mentagrophytes). Protocol wise we used a modified version of a basic time kill test format: In our procedure, samples from the leather shoe soles are stamped out using a leather punch to create consistent sizes for testing. These leather shoe sole samples are inoculated, placed inside a (new) sneaker (which is cleaned with alcohol to minimize contamination), and exposed to the UV device. Each inoculated shoe sole sample is removed from exposure to the UV device at the specified time point using aseptic technique. The inoculated shoe sole sample is then stomached for 60 seconds in a ringers solution. Dilutions from the ringers bag are performed on to agar plates which are then cultured. Enumeration of viable colonies is then preformed using a plate count. An initial sample not exposed to the UV light is also tested to ensure adequate recovery from the shoe sole samples.

   Basically speaking, the test is a (45 min per organism) time kill study where we recover the fungus by introducing them to ringers (saline solution) with agitation and then plating out the liquid and incubating to get a count for each time slot. The test sensitivity is > 100; so in the above chart this means that we were not able to recover anything from these samples.

   Since we were able to verify recovery of the two test organisms from the leather shoe sample not exposed to the UV light (initial result) we can say that the protocol used for enumerating the viable organisms on each leather shoe sole sample is accurate. The data indicates that we were not able to recover organisms from any of the shoe sole samples which were exposed to the UV light.”

   We were able to obtain the below result for your UV shoe device: No organisms were viable after 5 minutes exposure to the ShoeZap light.

   
3. The dangers of Shoe Sprays

   There are few studies on the effectiveness of shoe sprays on germs. Many experts believe shoe sprays are of low efficacy, and the effect is limited and short-lived. Others are concerned that the fungicidal chemicals in many shoe spray formulas leave a residue in footwear that is subsequently reconstituted by perspiration, subjecting the wearer’s feet to a potentially toxic environment.

   Lysol® is one common shoe disinfecting suggestion, even among healthcare professionals, however the warning label states: “DO NOT spray…on skin or on clothing. Precautionary Statement: Hazards to Humans and Domestic Animals. Caution: Causes moderate eye irritation.”

   Similarly, bleach is often recommended for footwear sanitizing, but it too leaves a toxic chemical residue that creates of hazardous foot ‘swamp’ feet are trapped in for 8-10-12 hours daily.

   Noxious and flammable fumes, aerosol dispersants and long-term costs are among other shoe spray concerns.

Here are additional references to research into fungus in footwear:

Recovery of dermatophytes from shoes and a shower stall

Ajello, L. and Getz, M. E.: Recovery of dermatophytes from shoes and a shower stall. J. Invest. Dermat., 22: 17–21, 1954.

Reinfection from shoes and socks in tinea pedis (athlete’s foot)

Broughton R. Reinfection from socks and shoes in tinea Pedis. Br J Derm. 1955;67:249-54

Killing of foot fungi in shoes using ultraviolet radiation

Gemeinhardt H.: Killing of feet fungi in shoes with ultraviolet rays. Z Gesamte Hyg (18(1):9-14, 1972 Jan.)

Isolation of dermatophytes from footwear with adhesive tape strips

Knudsen, A.: Isolation of dermatophytes from footwear with adhesive tape strips. Journal of Medical and Veterinary Mycology (1986) 25, 59-61

Zum Nachweis hautpathogener Pilze in der Fussbekleidung (Recovery of pathogenic fungi from footwear)

Polemann, G.: Zum Nachweis hautpathogener Pilze in der Fussbekleidung. Dtsch. Med. Wschr., 82 Jg.: 1871-72, 1957.

Some of Many References

Martin, Stephan B., Jr., Chuck Dunn, James D. Freihaut, William P. Bahnfleth, Josephine Lau, and Ana Nedelijkovic-Davidovic. "Ultraviolet Germicidal Irradiation: Current Best Practices." ASHRAE (2008): 28-36. Print.

Tianhong Dai, Mark Vrahas, Clinton Murray, Michael Hamblin. “Ultraviolet C irradiation: an alternative antimicrobial approach to localized infections?” NIH Public Access Author Manuscript

Corner-Kerr, et al. examined the effectiveness of UVC irradiation in antibiotic-resistant strains of Staphylococcus aureus and Entererococcus faecalis and MRSA in vitro, with inactivation rates were 99.9% at 5 seconds, 100% at 90 seconds.

In similar studies to above, Rao et al reported complete (100%) eradication of the microorganisms on agar at the UVC doses ranging from 5 to 15 seconds, at a distance of 10 cm.

Dean et al. evaluated the efficacy of UVC for treating corneal bacterial infections in vitro. The study demonstrated that a 1 second exposure to UVC was sufficient to induce 100% inhibition of growth for all the bacterial species tested

Sullivan and Conner-Kerr achieve a 99.9% inactivation rate obtained at 3-5 seconds for the bacteria (P. aeruginosa and Mycobacterium abscessus) tested. 15-30 seconds of UVC treatment was required to obtain 99.9% inactivation of the fungi (Candida albicans, Asperfullus fumigatus) tested