The strength of a sanitizer solution is measured using test strips that show the concentration of the active chemical (for example in ppm or percentage).

Basic idea

  • The most common way in food service and cleaning is to dip a sanitizer test strip into the solution and compare the strip’s color to the chart on the package.
  • The color change tells you if the sanitizer is in the “safe and effective” range, is too weak, or is too strong.

What exactly is being measured?

  • For chlorine or quats (quaternary ammonium), strength is usually expressed in parts per million (ppm) of active ingredient.
  • For alcohol-based sanitizers, strength is usually given as percentage by volume, such as 60–70% ethanol or isopropyl alcohol.

Other ways strength can be checked

  • Some kits or meters can measure sanitizer concentration and pH more precisely than simple strips, but the principle is the same: checking chemical concentration, not smell, foam, or appearance.
  • Visual checks, smelling, or using a food product probe are not considered valid methods for measuring sanitizer strength in safety guidelines.

Information gathered from public forums or data available on the internet and portrayed here.