TAMPA, FL — Hand sanitizers have surrounded me from elementary school field trips to competitive sporting tournaments in high school and college. Running water wasn’t always available before snack time, or for handling mouth guards between games. There are many questions I had about antimicrobial hand sanitizers, but had no clue where to start.
Scanning the presentation schedule for the annual conference of the International Association for Food Protection, I came across a session with Lee-Ann Jaykus. I was encouraged by multiple IAFP exhibitors to not pass up the Mondy morning discussion about the efficacy of hand sanitizers against resistant pathogens. The big idea I was aware of going into the session was that hand sanitizers are important for interrupting the transmission of bacteria and viruses via hands.
A professor at North Carolina State University, Lee-Ann Jaykus greeted her audience by saying, “I’m the Norovirus woman!” The room chuckled, as many IAFP attendees are fond followers of Jaykus’ Norovirus research.
The first idea Jaykus addressed was understanding what resistant pathogens are. They are bacteria, spores, and viruses which can be non-enveloped — resistant — or enveloped like influenza. How do these bugs become resistant? Hepatitis A is a perfect example, with it’s resilient protein capsid. A capsid is an outer protein coat of a virus; composed of very resistant, very packed proteins.
There are several things that resistant pathogens have in common including the fact that most are non-cultivable — you cannot cultivate them in a lab — and they tend to be difficult to detect. Jaykus also explained that the material for such research can be difficult to access. Not everyone is as fortunate as the professor who has access to government lab fecal matter.
Jaykus listed various product types of commercial hand sanitizers such as alcohol, benzalkonium and chloride.
“There really isn’t anything that will completely eliminate Norovirus on human hands,” she said.
She explained that product forumulation matters, product application matters, and validation and methodological issues, as well as regulatory and licensing matters, further complicate the situation.
Jaykus addressed the point of how to screen for product efficacy. She touched on “Vitro Suspension Assay,” a method of simply adding the pathogen to the product. She also described “In vivo methods,” which take place on the hands, using fingerpads. The fingerpad method typically involves putting the fingerpad in contact with the virus — approximately 10-20 micro liters — then exposing fingers to hand sanitizer in a vial for about 30 seconds. She also discussed other methods involving the whole hand, a “glove-juice method”, sanitizing wipes, or rubbing/elution.
Is there a best method? Jeykus’s answer is, “Nope, there is a lot of debate over the best method.”
She shared some of the issues with the methodology of this debate. First, many do not want to contaminate the entire hand. Controls are another factor as they help quantify. Also, the impact of rubbing alone is important to consider, Jeykus said, explaining that it’s difficult to separate efficacy from hand rubbing versus sanitizers. Thus, experiments are in the works to determine how well pathogens can be removed by rubbing alone.
Jeykus concluded that we need better methods to evaluate efficacy, reliable access to in vitro cultivation methods, product formulation effects, removal versus inactivation, persistence of activity, regulatory issues, and better products.
Last but not least, the most important key to prevention of infections? Hand washing, “the old faithful” as Jeykus called it, due to the impact of friction. The biggest issue with hand washing? Compliance, especially in the retail sector, which Jeykus observes as being “not practical” in busy times.
Jeykus affirmed my belief in paying attention to washing under fingernails, as she said fingernail beds are an area that is often neglected in hand washing. She also stated that singing the ABC’s while you wash your hands will ensure proper time allotment, as well as the fact that water temperature matters less than soap does.
I will still carry hand sanitizer in my purse and gym bag, but I will remember that hand washing with soap and running water is the first choice for interrupting the transmission of bacteria and viruses. I will also be practicing my ABC’s again, twenty years I first sang the song.
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