Purpose: A membrane filtration comparative study to demonstrate performance of different CCA brands in combination with matched membrane filters, according to ISO 11133:2014 and a shelf-life study using stressed CCA agar (72°C, 40 h), to demonstrate stability at 25°C and 60% humidity for 6 months minimum.
Methods: ISO 9308:2014 control strains selected: 3 for shelf-life and 4 for comparative. One hundred ml 0.9 % NaCl, containing the test organism, was filtrated according to ISO 11133:2014 using filters from own brand, Competitors A and B (comparative study only) and non-selective agar as reference. For shelf life, CCA was first stressed for 40 h at 72°C and stored at 25°C, 60 % humidity for at least 6 months. Productivity calculations were conducted according to ISO 11133:2014 with CCA acceptance criteria of ≥70%, according to ISO 9308-1.
Results: All CCA brands complied with the productivity specification of ≥70 % for all control strains. Productivity rates for Competitors A and B were lower than own brand CCA rates. Membrane application and removal on/from the media was more difficult with Competitors A and B. Shelf life demonstrated up to 6 months.
Significance: ReadyPlate 55 CCA 9308 and EZ-Pak Membranes ISO 9308-1:2014 and ISO 11133:2014 compliant kits for water testing filtration, optimize incoming QC costs of filter/media batch combination and reduce refrigeration storage. This solution is aimed at streamlining the ISO 17025 accredited laboratories incoming workflow, and increasing the technicians’ peace of mind.