How safe are your biocides?
The control of micro-organisms in cleanrooms and isolators requires the selection of biocidal chemicals, with a wide range of actives and ingredients – but do you balance efficacy with user safety?
It is important to use efficacious chemicals which are designed to kill micro-organisms; destroy cells. However, their modes of action are not so sophisticated that the chemical can 'sense' the difference between a bacterial cell and, say, a human epithelial cells.
Steris was contacted by a biotech firm, with an interest in finding an alternative chemistry to the aqueous aldehyde based product. The aldehyde product was being routinely used for spore control in their aseptic filling area, antibody scale-up area, antibody production area, main isolator and transfer isolator and effectively maintained these areas. However, the decision to investigate an alternative spore control agent was made due to rising safety concerns over the use of aldehydes.
Two alternative chemistries were considered by the biotech firm, chlorine dioxide and the Steris product, a hydrogen peroxide/peracetic acid blend. After initial studies, the chlorine dioxide solution was dismissed due to its' potentially corrosive nature and other toxicity issues. The hydrogen peroxide/peracetic acid blend, was evaluated further as it satisfied the following criteria listed by the biotech firm
- Low-level of irritation to personnel
- No residue after application
- Shorter kill time (when compared to aldehydes)
- No product activation required
- Respirators may not be required during application
- Passes efficacy testing standards
- Extensive data package including: efficacy, toxicity and corrosiveness testing
- Safe for common cleanroom materials.
Results The in vitro testing was done according to the AOAC Germicidal Spray Products as Disinfectants testing protocol. The test was performed using the following organisms: Pseudomonas aeruginosa ATCC #15442, Salmonella cholerasuis ATCC # 10708, Staphylococcus aureus ATCC #6538, Staphylococcus epidermidis (in-house isolate) and Alternaria species (in-house isolate). Per the AOAC protocol, none of the test vessels displayed growth. On a laboratory scale, this demonstrated that the target organisms were effectively eliminated. The second part of the evaluation involved an in situ evaluation of the blended product within the biotech facility. Data showed a reduction in the number of colony forming units collected on each media type where growth was found. The product was capable of effectively eliminating gram-positive and gram-negative organisms, molds and all species of Bacillus found. Conclusion In the final report, the biotech firm which conducted these studies concluded SporKlenzJ Ready-To-Use proved to have worked effectively in all areas where it was applied and met all three acceptance criteria: it passed the efficacy testing, it reduced both the microbial counts and types of microbial flora in all of the areas where it was applied, and none of the post-sanitisation environmental monitoring data exceeded the established limits. With the efficacy data in place, and toxicity information reviewed, this biotech firm moved away from aldehydes to a much safer product.
T: +44(0)1256 840 400 Email: Phil_Smith@steris.com