disinfectant chemical and bucket with cotton cloth

This oft-misunderstood phenomenon is garnering greater attention in healthcare facilities

Healthcare-acquired infections are a costly, ever-present threat in hospital environments, which is why proper surface cleaning and disinfection can mean the difference between life and death — literally. For this reason, environmental services (EVS) workers play a vital role in implementing cleaning products and procedures that mitigate the spread of germs and prevent cross-contamination.

Disinfectants containing quaternary ammonium chloride (also known as quats) are a popular choice in the industry because they are both effective and inexpensive. However, quats are also subject to a phenomenon known as quat binding that can render them ineffective.

“Quat binding occurs when quaternary ammonium compounds make contact with materials, such as cotton, that inactivate or impair the germ-killing performance,” notes Allen Rathey, principal, Healthy Facilities Institute University, Boise, Idaho.

Rather than being released onto the surface, the positively-charged disinfectant molecule is attracted to the negatively-charged cotton cloth being used to apply the disinfecting solution. This reduces the disinfectant’s parts per million (ppm) or concentration by up to 50 percent in as little as 10 minutes, according to Heidi Wilcox, microbiologist and president of Wilcox EVS, Haverhill, Massachusetts.

“What happens is, EVS staff is putting U.S. Environmental Protection Agency (EPA)-registered pesticide products and active ingredients into the environment, and it’s not killing as it’s supposed to because of the concentration decrease,” says Wilcox. “So quat binding can pollute your indoor air and surfaces while not killing what you set out to kill. It’s a recipe for disaster.”

Putting Quats To The Test

While the issue of quat binding has been a topic of discussion for some years, many custodial executives are still uninformed — or worse, unconcerned.

“We started hearing about this issue two or three years ago,” says Phil Carrizales, director of the janitorial and sanitation division at Acme Paper and Supply, a jan/san distributor in Jessup, Maryland. “A lot of people in healthcare don’t understand what it is or how it happens. Some choose to act; others are slow to react.”

According to industry experts, quat binding often remains undetected because there is no visual evidence that it has occurred, save for a test to measure the solution’s efficacy.

“Facilities need special equipment to conduct a titration test,” explains Bill McGarvey, director of training and sustainability at Philip Rosenau Co. Inc., a distributor in Warminster, Pennsylvania. “The test is a little lengthy and complicated, but it will determine the solution’s parts per million. Cleaning personnel can then draw assumptions based on what products they’re using and their methodology.”

To conduct the test, the user mixes the solution according to the manufacturer’s instructions, paying close attention to the disinfectant’s required parts per million. Before adding any cleaning mops or rags, the user tests the clean solution to ensure that it is the correct parts per million. Next, the user adds the cleaning tools/materials and retests the solution after five minutes.

“If the results show anything less than the required parts per million, you’re depleting the active ingredients in your disinfectant,” says Darrel Hicks, infection control consultant and author of Infection Prevention for Dummies, St. Charles, Missouri. “After about an hour, you might as well be using water.”

While hospitals do not routinely test quaternary ammonium chloride disinfectants for quat binding, many use an ATP meter to assess the cleanliness of surfaces.

“When we go into a hospital, we use their ATP testing device to determine if they’re killing the microorganisms that they should be killing,” says Carrizales. “If they’re not, it could be an indication that they need the quat strip test to determine if they’re distributing the required parts per million.”

In most cases, Carrizales’ hospital customers that discover quat binding issues are caught off guard.

“It’s a wake-up call for them to look into viable alternatives and possibly change the way they’re cleaning,” he says.

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Tips To Prevent Quat Binding