What is Quat Binding?

Quat binding, or quat absorption, is the process by which quaternary ammonia cations are neutralized in a cleaning solution, reducing its germ-killing efficacy. It's a common issue that can't be detected by the naked eye and may even enable the growth of disinfectant-resistant germs on surfaces in dining rooms, breakrooms, kitchens, offices, and restrooms. Uncontrolled quat absorption can have a serious impact on the health and safety of employees and visitors in foodservice operations, healthcare facilities, and other institutions. Read on to learn more about what quats are, how quats work, and how to prevent quat binding in your cleaning solutions.

What Is a Quat, Anyway?

Quaternary ammonium compounds (quats) are a group of active ingredients found in many common cleaning solutions, such as floor cleaners, dishwashing liquids, disinfectant sprays, window cleaners, and antimicrobial surface cleansers.¹ This group of disinfectants is favored by many healthcare and foodservice facilities because it's extremely effective at killing a broad spectrum of illness-causing microbes – including bacteria, fungi, and enveloped viruses.²

How Do Quaternary Ammonium Compounds Kill Bacteria & Other Pathogens?

To destroy germs, positively charged quat cations in the cleaning solution are attracted to negatively charged microbial membranes. By bonding to the organism's anionic (negatively charged) exterior envelope, the quat cations break down the cell wall, killing the pathogen.³ Unfortunately, placing any anionic material in the cationic cleaning solution and allowing it to sit can prematurely activate this bonding, rendering the quats useless against bacteria and viruses. Because of this, quaternary ammonium compound disinfectant is only effective as long as the quat cations remain active and able to form ionic bonds with pathogens.

How Does Quat Binding Happen?

Quat absorption occurs when quat cations bind with negatively charged materials before the compound is used to clean a surface.⁴ This most commonly happens with woven cleaning cloths made of cotton, terrycloth, and microfiber. Many types of cleaning cloths are naturally anionic, meaning they are negatively charged just like microbial envelopes.⁵ Some are even deliberately charged (such as dry dusting cloths), promoting ionic bonding to attract dirt, dust, and hair like a magnet.

As a result, the cleaning cloth itself attracts and binds with the disinfecting quat cations, reducing the number of active quats in a cleaning solution and diluting its concentration level – meaning much of the active ingredient gets neutralized before the liquid even touches the surface it's supposed to be cleaning.

Quat binding can happen quickly, and because of how quaternary ammonium compounds kill bacteria, this binding can significantly reduce the germ-killing power of a cleaning solution within minutes.⁶ Since there's no way to tell if binding has occurred by looking at a cleaning solution with the naked eye, it's possible to unknowingly clean with a fluid that has a greatly reduced quat concentration, leaving behind dangerous pathogens.

Even worse, the microbes that survive the initial cleaning can quickly reproduce and develop cleanser resistance,⁷ making it even harder to disinfect surfaces on the next pass.

How to Prevent Quat Binding

Quat binding can be a big deal, but preventing it doesn't have to be. There are some simple cleaning routine changes that, when integrated into daily cleaning activities, can greatly reduce binding and preserve the effectiveness of quaternary ammonium compound cleaning solutions.

Keep Rags Out of Buckets

Never let rags sit in containers of disinfectant. This is the primary cause of quat binding. If the positively charged cleaning solution isn't left exposed to the negatively charged cleaning cloth, they won't have the opportunity to bond.

If possible, avoid dipping the cloth into the container at all. The best method for using a sanitizing cleanser is to spray the solution directly onto a surface with a spray bottle, then wipe it clean with a cleaning cloth. If you must dip the cloth into the container, use a new one each time. You can use disposable cloths, or you can throw the used rag into the laundry and grab a fresh one after each cleaning routine is performed.

Switch to Disposable Cloths

As mentioned above, you can opt for disposable cleaning cloths instead of reusable woven cloth options. Some disposable cloths don't bind with quat cations like woven cleaning rags can, making them a safer choice for disinfecting procedures. It's important to check the label on disposable cloths to ensure they're not "charged" to attract debris, or they'll bond with quats even more quickly than regular cleaning rags. Use each cloth once and then discard it, and never leave it soaking in a container of cleaning fluid, even if it's disposable.

Increase Cleanser Concentration

To offset binding, users can mix cleansers at a higher concentration (measured in parts per million, or PPM) to ensure the solution will still be effective as a disinfectant if binding occurs. For some cleaning chemicals, mixing solutions at an increased concentration can be dangerous, so it's important to thoroughly read container labels and follow all safety precautions when working with chemical cleansers.

Wearing safety equipment such as rubber gloves and a mask is a good way to avoid exposure to highly concentrated chemicals while cleaning and should be a standard safety precaution regardless of cleanser concentration.

Mind Your Mop

Mops, unlike most rags, must be dipped into the bucket of cleaning solution repeatedly during the mopping process. To minimize binding, don't leave the mop in the bucket between cleaning tasks or while transporting the bucket from room to room. Instead, thoroughly wring the mop out and place it in the wringer or on the built-in platform that some mop buckets provide. Leave the mop there until you reach the next area in need of cleaning.

As with cleaning cloths, disposable mop heads are also available and may help avoid binding. When using disposable mop heads, users should still follow quat binding prevention practices and never leave the mop head soaking in the bucket.

Change Cleaning Solution Regularly

Even when you take precautions to minimize quat absorption, it can still occur over time. Additionally, as a cleansing liquid mixes with dirt and germs from rag or mop dunking, it begins to lose its effectiveness, regardless of quat levels. When working with open containers of disinfectants, remember to dispose of the old cleaning solution periodically and mix a new batch. Throughout a shift, users should keep an eye out for cloudiness, dirt, floating film, or other visible signs that the solution needs to be replaced. Never reuse buckets of mop water or disinfectant that have been sitting out overnight.

Use Quat Test Strips

To track possible quat absorption, purchase water test strips to check the quat concentration in containers of cleaning chemicals. If the quat test strips reveal the cleaning ability has been compromised, the solution should be discarded and replaced with a fresh batch. Quat test strips are the most precise method to evaluate and track the concentration of cleaning solutions and are an effective tool to mitigate the danger of inadvertent quat absorption.

Quat Binding & Your Facility

Quat binding can compromise cleaning and sanitation procedures, impairing common cleaning solutions in undetectable ways. If enough microorganisms survive, disease-causing pathogens such as staph aureus, salmonella, influenza, and aspergillus can begin to reproduce on surfaces, spreading from one person to the next.

Although the consequences of undetected quat binding can be serious, it's fairly simple to prevent. Most operators invest a dedicated portion of their budget into cleaning supplies and pay employees to perform sanitation procedures. Incorporating some additional precautions into daily cleaning routines at any establishment can prevent the spread of illness, ensure the best return for your budgetary investment, and promote a safe, clean environment for all visitors.

References

1. Quaternary Ammonium Compounds. ChemicalSafetyFacts.org. Accessed May 2021.
2. Guideline for Disinfection and Sterilization in Healthcare Facilities (2008). Centers for Disease Control and Prevention (CDC). Accessed May 2021.
3. Quaternary Ammonium Compounds. Science Direct. Accessed May 2021.
4. What Is Quat Binding and Why It Must Be Prevented. Clean Link. Accessed May 2021.
5. Wipe and Disinfectant Compatibility. Cleanroom Technology. Accessed May 2021.
6. Preventing Quat Binding in Healthcare Facilities. Healthcare Facilities Today. Accessed February 2024.
7. Disinfectants Cause Some Bacteria to Adapt, Thrive. Live Science. Accessed May 2021.