Formaldehyde sterilization biological indicators

Strip

The strips are paper strips inoculated with Geobacillus stearothermophilus spores used to optimally verify sterilization with chlorine dioxide.

The strip is usually enclosed in a paper sachet, which must be placed inside the load and subjected to the sterilization cycle, during which the chlorine dioxide comes into contact with the spores.

Once finished, the strip must be removed from the sachet and incubated for 7 days in Soybean Casein Digest Broth (TSB). Any cloudiness of the medium indicates bacterial growth and therefore sterilization failure. Broths with pH indicators are available which, by changing color with bacterial growth, allow a significant shortening of the incubation time to be validated.