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The New Concern About Effective Disinfecting

 

Quat binding and its effect on disinfection

 

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Infection Control
 
 
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The New Concern About Effective Disinfecting
 

A term cleaning professionals should know much more about is ‘quat binding’. If you have not heard of it before, join the club. While quat binding has been discussed for a few years now in some areas of the world, it is just inching its way globally and into the professional cleaning industry – ironically enough, where it is actually most needed. ‘Quats’ refer to quaternary ammonium chlorides, which are the active ingredients in most disinfectants used every day around the world. One of the most common quats is alkyl-dimethyl-benzyl-ammonium chloride or ADBAC, which should be listed as a key ingredient on product labels. ‘Binding’ refers to the absorption of these quats into the cleaning cloths we use to clean counters, restroom fixtures, tables such as in medical facilities, and other surfaces as well as into the mops used for floor cleaning. When this absorption occurs, the disinfectant loses its killing power and when this happens, while you may think you are effectively disinfecting a surface, in reality you are not.

Just to show you how fast this can happen, one manufacturer of cleaning solutions placed a cleaning cloth in a bucket containing water and a properly diluted amount of water. The potency of the disinfectant/water combination was tested before the cloth was inserted into the bucket. It was found to be 800 PPM or parts per million. It was then tested again after the cleaning cloth soaked in the bucket for ten minutes. What they found was that half of the disinfecting efficacy (effectiveness) of the disinfectant was gone! This means that the effectiveness of the disinfectant had been reduced to 400 PPM.

Why this happens is pure - if not unfortunate – science. The quats contain positively charged ions, which are attracted to the fibers in the cleaning cloth/mop that contain negatively charged ions. Not only does this cause the disinfectant to lose its killing power, but it is an ongoing process. As the cloth is used and becomes more soiled, the disinfectant efficacy continues to diminish.

Addressing the problem

What we have learned is that cleaning cloths/mops made of cotton and rayon are the chief culprits when it comes to quat binding. So one option suggested has been to select cloths/mops made of different man-made fibers. One that seemed promising initially was polyester. It does not absorb the quats like cotton and rayon but has its own set of problems. When used to disinfect surfaces, it was found to exhibit poor absorbency, which limited surface cleaning and the effectiveness of the disinfectant. Further, the usefulness of the polyester varied as it was used. This means it could prove more effective on some areas than others with little rhyme or reason to it.

Another way the problems with quat binding are being addressed is to use non-woven cotton cleaning cloths and remove any bleach used in processing. It is believed that the bleach in the cotton fibers may be playing a role in absorbing the quats. However, the jury is still out as to how effective this will be. This means, at least for now, addressing the problems created by quat binding is in the dependable hands of cleaning professionals. Amongst the things you can do, are the following:

Adjust the dilution ratios: We always have to be careful about how disinfectants are diluted. Typically the manufacturer’s dilutions recommendations have been scientifically tested to ensure the product works effectively. Also, too much disinfectant left on a surface can leave too much chemical residue, resulting in re-soiling. That said, if the manufacturer suggests a more powerful dilution ratio, it might be best to use this ratio for all disinfecting purposes. That way you are working with a more potent disinfectant, which will likely stay potent longer before quat binding takes over.

Spray-then-wipe: Do not leave a cleaning cloth in a bucket of diluted disinfectant. We have already mentioned how quickly the disinfectant loses its power. However, spraying the disinfectant directly on the surface to be cleaned and then wipe will definitely help ensure the full potency of the disinfectant is maintained. This requires that you change cleaning cloths very frequently, perhaps three or four times when cleaning just one restroom. The more soiled the cleaning cloth, the less effective will be its disinfecting potential.

Spray-and-vac: What probably is the most effective approach to take, and certainly if there are serious concerns about contamination, is to use a spray-andvac cleaning system. More often known as ‘no-touch’ cleaning systems, no cleaning cloths or mops are used at all. The system applies the disinfectant to floors, counters, and all areas to be cleaned; power rinses them off; and then vacuums up the cleaning solution/ disinfectant along with contaminants. No quat binding takes place.

Thoughts on disinfectants

Compounds containing sulphur were used in ancient times as disinfectants. They were developed by scientists and doctors in the Middle East who communicated this knowledge to Europeans. In some cases, they proved very effective, but not always. Today, most registered-disinfectants are very effective. You could compare them to the ‘miracle’ drugs of 60 years ago such as the polio vaccine and penicillin.

The development of disinfectants has helped ensure that when we are using a disinfectant properly, it will kill a wide range of germs and bacteria along with the specific germs and bacteria we are trying to address. Now that we know about quat binding, we can make sure these ‘miracle’ disinfectants are still doing the job they were designed to do.

About the Author: Marc Fergusson is International Business Development Manager for Kaivac, manufacturer of No-Touch Cleaning ™ and OmniFlex™ Cleaning Systems.