Disinfectants

Common Disinfectants

Chemical Compound Gram + Bacteria Gram - Bacteria TB-like Bacteria Fungi Virus Best pH range for activity Activity when organic matter present Common uses **
Chlorhexidene SA* SA SA SA Most Wide range Good E/P/F
Formaldehyde and aldehydes ++ ++ ++ ++ ++ Wide range Good E/P/F
Chlorine Chloramines ++ ++ SA ++ SA Acid Very poor CS/E
Iodophors ++ ++ SA ++ SA Acid Fair to poor CS/E

Sodium hydroxide (Lye)

++ ++ SA ++ ++ Alkaline Good P
Quaternary ammoniums ++ + No SA SA Alkaline Fair CS/E
Phenols ++ ++ + SA SA Acid +Good E/P/F

* SA-some activity
**E-equipment; P-premises; F-footbaths; CS-clean surfaces
(Adapted from Purdue University Extension Bulletin PIH80)

Bleach Dilutions

  • Commercial chlorine bleach contains 5.25% sodium hypochlorite in aqueous solution and 50,000 ppm available chlorine.
  • Bleach has no detergent activity, always requires extensive cleaning beforehand.  
  • Stability when diluted is 24 hours.  
  • Recommended contact time is 10 minutes. Rinse is required.
Sodium hypochlorite % Bleach Solution Ratio Bleach Dilution ppm (available chlorine) Comments
**Always use on cleaned surfaces.
0.025% 1:200

1.5 Tbsp (0.6 oz) bleach to 1 gallon water

250 ppm Common household use
0.1% 1:50 1/8 C (1 oz.) bleach to 1 gallon water 1000 ppm Commonly used
0.16% 1:32

1/2 cup (4 oz.) bleach to 1 gallon water

1562.5 ppm Commonly used
0.5% 1:10 1.5 cups (12 oz.) bleach to 1 gallon water 5000 ppm This is a very strong solution and should be used on a limited basis.