Disinfectants

By Benjamin D. Tanner, Ph.D. - President, Antimicrobial Test Laboratories

Definition: Disinfectants are chemicals used on inanimate surfaces to rapidly inactivate microorganisms.

Before we get started, let's explore the difference between disinfectants and antibiotics: Disinfectants are different from antibiotics, though both kill germs and both are considered to be antimicrobial. Generally speaking, disinfectants destroy many components of microorganisms at once and are not safe to ingest or inject. Antibiotics, on the other hand, usually disrupt one or a few parts of microorganisms and have relatively little toxicity to the body.

Most disinfectants are comprised of different ingredients including water, surfactants (detergents) and fragrances. These complete, shelf-stable, solutions are called formulations. Within a formulation, the chemical that kills microorganisms is referred to as the active ingredient.

Some common active ingredients are listed below along with major benefits and drawbacks:

Active Ingredient	Benefit	Drawback
Acids	Robust, Broadly Active	May Harm Surfaces
Sodium Hypochlorite (Bleach)	Inexpensive, Broadly Active	Poor Chemical Stability
Quaternary Ammonia	Inexpensive, Fast-Acting	Not Broadly Active
Alcohols	Fast-Acting, Stable	Flammable
Metal Ions (e.g. Silver Ions)	Safe, Potent	May Discolor Surfaces

Some of the active ingredients listed above can also be used to destroy microorganisms on the surface of the body. When used to kill microorganisms on the body, they are referred to as antiseptics. When active ingredients are used on the hands, they are referred to as hand sanitizers. A few potent active ingredients can also be used in high concentrations to sterilize medical equipment, such as surgical endoscopes, without heat. Formulations that sterilize medical equipment are called cold sterilants.

Disinfectants and inanimate surface sanitizers are regulated by the United States Environmental Protection Agency as pesticides (EPA considers bacteria, viruses, parasites and fungi to be pests, therefore subject to regulation by the Federal Insecticide, Fungicide and Rodenticide Act). EPA requires disinfectants sold in the United States to be thoroughly characterized in terms of their safety and efficacy and meet specific labeling instructions before they go to market.

Product labels found on disinfectants in the United States bear a great deal of information, all of which must be approved by EPA. Click on the bottle to explore a United States disinfectant product label.

These test methods are commonly used by EPA to judge the antimicrobial efficacy of disinfectants and set germ-related claims:

	AOAC Use-Dilution Test for Disinfectants
	AOAC Germicidal Spray Products Test
	AOAC Presaturated Towelette Disinfection Tests

Before a disinfectant can be sold in the U.S., EPA typically requires a series of acute toxicity tests on various animals to characterize the risks that the disinfectants will pose to humans and to set label warnings. Some of these tests are painful. Antimicrobial Test Laboratories does not conduct animal testing or support its use as a means to characterize the risks posed by disinfectants.

Thanks for exploring disinfectants at Antimicrobial Test Laboratories! Check back soon for more information and updates!

This material is for educational purposes only.