Cleaning and Hygiene Products (Why 70% Isopropyl Alcohol)

Ever wondered why cleaning products and hand sanitizers are mixed at only 70% and not used at 99.9% isopropyl alcohol?

The presence of water in isopropyl alcohol is a crucial factor in destroying or inhibiting the growth of pathogenic microorganisms.

Water act as a catalyst and plays a key role in denaturing the proteins of vegetative cell membranes.

70% IPA solutions penetrate the cell wall more completely which permeates the entire cell, coagulates all proteins and therefore the microorganism dies.

Another plus side of having a higher water content is, alcohol dries faster than water, therefore by having more water, this slows down evaporation which therefore increases surface contact time allowing it to be more efficient in destroying microorganisms.

Any mix below 60% isopropyl alcohol will not be effective and when the mixture is above 90% the coagulation of the proteins is instant. This then forms a protective layer which protects other proteins from coagulation effectively making the product inefficient.

This means the leeway for cleaning products is between 60% and 90% isopropyl alcohol with 10% to 40% purified water. 70% / 30% is the preferred mix by medical professionals

SaFA Training & Consultancy Ltd run courses in Bio-Hazard Awareness and through one of our partners, have delivered these to Staffordshire Police Forensic Department