How to Choose a Sanitizer or Disinfectant
There is no single best disinfectant. The right choice depends on what you are treating, which germs you need to control, how long the product can stay wet on the surface, and what it will do to people and materials. These are the questions professionals ask.
Sanitizing, disinfecting, sterilizing
- Cleaning removes dirt and organic matter. It always comes first: disinfectants work poorly on dirty surfaces.
- Sanitizing reduces bacteria to a safe level, typically on food-contact surfaces.
- Disinfecting kills most microorganisms on surfaces and objects, but not necessarily bacterial spores.
- Sterilizing destroys all microbial life, including spores.
Match the method to the risk
Healthcare uses the Spaulding classification, described in the CDC disinfection guideline, and it is a useful way to think anywhere:
- Critical items enter sterile tissue or the bloodstream (surgical instruments): they must be sterilized.
- Semicritical items touch mucous membranes (some medical scopes): they need high-level disinfection.
- Noncritical items touch only intact skin or nothing at all (floors, bed rails, tables): low-level disinfection is enough.
The common options
| Agent | Strengths | Watch out for |
|---|---|---|
| Chlorine (bleach) | Cheap, fast, broad spectrum | Corrodes metals, irritates eyes and lungs, inactivated by organic matter, must never be mixed with ammonia or acids |
| Hydrogen peroxide (incl. accelerated formulas) | Broad spectrum, breaks down to water and oxygen | Can damage some metals and finishes at high strength |
| Quaternary ammonium compounds (“quats”) | Good cleaners, low odor, gentle on surfaces | Weaker against some viruses and spores; can be absorbed by cotton cloths |
| Alcohol (60–90%) | Fast on small surfaces and skin | Evaporates quickly, flammable, not for large areas |
| Ozone (in water or gas) | Very strong oxidizer, made on site, leaves no residue | Gas is toxic to breathe; must be used in controlled systems or unoccupied spaces, with monitoring |
Read the label, follow the contact time
In the United States, products that claim to disinfect must be registered with the EPA, and the label is the instruction manual: it states which organisms the product kills, at what dilution and for how long the surface must stay wet (the contact time). A disinfectant wiped off after ten seconds when the label says four minutes has not disinfected anything.
Where ozone fits
Ozone is approved by the U.S. Food and Drug Administration as an antimicrobial agent for food treatment, storage and processing, and dissolved ozone is widely used for drinking water, bottled water and produce washing. It is a strong choice where it can be generated and controlled on site: water systems, laundries, food processing and treatment of unoccupied rooms. It is not a product to spray around people: the EPA warns that ozone at concentrations that are safe to breathe does little to disinfect air, and higher concentrations harm the lungs.