ISO 22196 is used to determine the antibacterial activity of treated non-porous surfaces such as plastics. A 5 x 5 cm section of product is inoculated with the relevant bacteria, Staphylococcus aureus and Escherichia coli are referenced in the standard but the method can be adapted for other bacteria. A 4 x 4 cm coverslip is placed on top to ensure contact with the active over the whole area. The inoculated samples are then incubated at room temperature in a humidified chamber for 24 hours. The material and coverslip are then washed with a liquid neutraliser or similar to recover remaining bacteria. The amount of bacteria surviving on the test article is quantified and the antibacterial activity calculated.
- Required bacteria: Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative), can be adapted for other species on request.
- Sample requirements: 5 x 5 cm control and antibacterial specimens (sterile or can be sterilised)
- Contact time: 24 hours, other contact times can be added
- End point: Colony counts
- Efficacy: Not set by standard, to be agreed on by all interested parties