P2-32 Performance Evaluation of MilliporeSigma ReadyPlate 55 Chromocult Coliform Agar (CCA) ISO 9308 and EZ-Pak Membrane Filters for Membrane Filtration Applications, in Compliance with the New ISO 11133:2014 Standard and ISO 9308-1:2014

Tuesday, August 2, 2016
America's Center - St. Louis
Lisa John, Merck KGaA, Darmstadt, Germany
Regina Petrasch, Merck KGaA, Darmstadt, Germany
Sigrid Von Der Weiden, Merck KGaA, Darmstadt, Germany
Michael Gampe, Merck KGaA, Darmstadt, Germany
Charlotte Lindhardt, Merck KGaA, Darmstadt, Germany
Sabrina Horn, Merck KGaA, Darmstadt, Germany
Samuel Santiago, Merck KGaA, Darmstadt, Germany
Tommaso Ronconi, Merck Group, Molsheim, France
Introduction: To detect Escherichia coli and coliform bacteria in water, ISO 9308-1:2014 specifies membrane filtration and Chromocult Coliform Agar (CCA). ISO 11133:2014 is mandatory for the culture media, requiring validation of EACH membrane filter batch with EACH culture media batch, considerably increasing workload and costs for testing laboratories.

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.