Hand Contamination Study Summary
Germs Stick to Hands Washed with Contaminated Soap
The soap in one of four refillable bulk soap dispensers in public restrooms is contaminated, according to studies conducted by academic researchers.1
New studies show that contaminated soap contributes to unsafe conditions beyond the dispenser, because contaminants stay on hands. Even worse, these contaminants can be transferred from washed hands to other surfaces, according to an independent laboratory that is a leading resource for antimicrobial product testing.
The soap in contaminated dispensers contains potential disease-causing organisms including Klebsiella pneumoniae (which could cause pneumonia, bronchitis, and other respiratory infections), and Serratia marcescens (which could cause infections of blood, wounds, eye infections, urinary tract, and the respiratory tract).
To analyze whether or not bacteria is transferred to other surfaces by hands washed with contaminated soap, two separate studies were conducted. The studies evaluated the presence of bacteria on the hands of people who washed their hands with contaminated soap, and assessed the potential of bacteria being transferred from hands to another surface.
Study participants’ hands were tested for contamination using a modified method specified by the US Food and Drug Administration (FDA). Common skin cleanser detergents contaminated with the Klebsiella pneumoniae and Serratia marcescens organisms were used.
Study participants were tested for these two bacteria, and then washed their hands using one of three different soaps: uncontaminated hand soap, soap contaminated with Klebsiella pneumoniae, or soap contaminated with Serratia marcescens. To replicate conditions typically found in bulk soap dispensers in public restrooms, the level of contamination in the soap was varied, and two different handwashing techniques were used.
The amount of bacteria present on each hand before and after handwashing was measured.
Study results showed that participants who washed their hands with uncontaminated soap had none of the contaminating bacteria on their hands after washing. For those who washed their hands with the tainted soap, these bacteria were present on their hands after handwashing, especially when there was a high level of soap contamination.
It is known that washing hands with contaminated bulk soap results in contamination of the hands.
This research also shows that bacteria left on hands after the use of contaminated soap can be transferred to other surfaces. This is also substantiated by other published literature.2,3
“Bulk hand soap dispensers are susceptible to contamination, and can contain unsafe levels of bacteria. There is no protocol for cleaning and sanitizing these refillable dispensers. Even when someone attempts to clean a bulk soap dispenser, it is time-consuming and impractical. Facilities managers cannot trust that bulk soap dispensers are free of bacterial contamination,” said Nicole Koharik, marketing manager, GOJO Industries.
Koharik continued, “We have suspected for some time that bacteria stays on hands washed with contaminated soap from bulk dispensers, and this study confirms our fears. Bulk soap contamination is an unnecessary health risk. The need to use factory-sealed containers for hand soap in public restrooms, rather than dispensing bulk soap through reusable, fillable containers, is a healthier choice - and some might say the only choicein order to avoid the bacterial contamination of hands and of surfaces touched by those hands.”