Facility Hygiene Solutions Blog

The Science of Disinfectants...

Written by Paul Woolfrey | Mar 2, 2021 1:54:00 PM

Helping you make the right chemistry choices when disinfecting

Disinfectants in the United States are regulated antimicrobial pesticides. In Canada they are regulated as drugs. These are chemicals which kill things, specifically pathogens or germs. Do not take any disinfectant lightly and make sure you are using the correct or best disinfectant choice for your need. ALWAYS read both the product label and the safety data sheet (SDS) carefully before using. The label is the law. Disinfectants are ONLY to be used in a manner which is consistent with its label!

Disinfectants in the USA are regulated by the EPA and carry an EPA registration number on their product label. Disinfectants in Canada are regulated by Health Canada and carry a D.I.N. (drug identification number) on their product label. These agencies accept the liability for the products being effective on the pathogens claimed on the label and when used according to the label. The label claims are based on scientific testing of the active ingredients, which are also stated on the label. There are several prominent chemistry choices used for disinfectant active ingredients in the North American cleaning market. Our purpose here is to help you understand those choices, including their strengths and weaknesses.

 

Chlorine (bleach or sodium hypochlorite)

Pros: widely used, easy availability, low cost, quick kill, effective on a wide range of pathogens including blood and body fluid borne pathogens.

Cons: dangerous, lung and eye irritant - major cause of eye damage & injuries, highly reactive, corrodes metals, short shelf-life/inactivated by light, poor cleaner, discolors (bleaches), reaction by-products are harmful to the environment.

 

Quats (quaternary ammonium compounds)

Pros: widely used, easily available, low cost, stable - good shelf-life, easy to use, highly dilutable, good cleaner, some residual bio-static properties when not rinsed

Cons: lower level disinfectant (example: ineffective on non-enveloped viruses), longer kill times, eye irritant, do not mist or fog due to potential nose and throat irritation, toxic to fish, persistent in the environment and promotes antimicrobial resistance which limits effectiveness of antibiotics.

 

Hydrogen Peroxide (oxygen bleach)

Pros: steadily increasing usage, fast kill times, higher cost – (low cost as an unformulated product but higher costs with increased formulation), effective on wide range of pathogens, excellent cleaner, safer than bleach and quats, sustainable (quickly breaks down into water and oxygen), occurs naturally in the environment.

Cons: highly reactive, low stability including to light, skin and eye irritant (dissolves fats and denatures proteins almost instantly), corrosive to metals, higher cost (see above), can discolor or bleach.

 

Thymol (botanical)

Pros: considered safer and less harmful to the planet than conventional disinfectants, however thymol may be natural or derived synthetically, low toxicity, mild skin and eye irritant, requires less PPE, often does not require rinsing, stable.

Cons: strong odor, expensive - most are ready to use versions which means you are transporting a lot (less sustainable) and paying for a lot of water, moderate range of kill, most thymol- based products have longer kill times.

 

NOTE: when comparing the cost of use for various disinfectants one should consider the following:

  • The chemical use cost which includes diluted end use costs when purchasing those disinfectants which are available as concentrates and super concentrates. Some chemistries disinfect at dilutions of 1 part of product to 256 parts of water. These can be considerably less costly than ready to use disinfectants.
  • Ready to use disinfectants (non-dilutable) often have more active ingredients, plus can be formulated with solvents etc. which enhance effectiveness - including shorter kill times.
  • The labor cost & productivity loss required to support the various kill times (wet contact kill times can vary from as little as 30 seconds to 10 minutes depending on the type of active ingredient, its concentration, and the targeted pathogen). Time is money for many people.
  • Concentrated products consume less packaging and require less transport, things which are beneficial to our planet

 

to learn more about the disinfectant products we offer.

This content is not meant to discuss all disinfectant chemistries nor the various products which may use more than one type of active ingredient in their formulation.