The residual effect of disinfectants

Residual activity describes the length of time a disinfectant remains effective after being applied to the skin or surfaces and protects the treated area from recolonization by germs.

Most modern disinfectants rely on a combination of fast-acting alcohols and somewhat slower but more persistent biocides as residual-active ingredients. The alcoholic components provide immediate disinfection, but evaporate relatively quickly in the air.

Residual-active ingredients do not evaporate, or do so only very slowly, and therefore remain active in the treated area for longer. Long-lasting residual activity is important, for example, in hand disinfectants used in operating rooms, during surgical procedures, or when inserting peripheral venous catheters.

Common residual-active ingredients include antiseptics such as chlorhexidine (CHX), which is also frequently used in mouthwashes, and octenidine, which is also found (usually together with phenoxyethanol) in wound disinfectant preparations.