ISO 6222 (1999) method: Total flora

Process control Water quality 

Enumeration of culturable micro-organisms - Colony count by inoculation in a nutrient agar culture medium

  • 1 Quantitative process control with RM-AQUA

    • Growth. The characteristic reaction of on YEA
    Characteristic reaction: Growth.

    Best Practice

    The multi-strain RM-AQUA contains Escherichia coli WDCM 00013, Pseudomonas fluorescens , Enterococcus faecalis WDCM 00087. This material can be used for several specific standards.The influence of interfering bacteria is also performed. It is easy to use by making one serie of dilution. This material is designed for water analysis

    1. Use a quantitative reference material (RM-AQUA) with a known number of Microorganisms.
    2. Defrost the material at room temperature for 30 minutes.
    3. Mix well before use and dilute the material so countable numbers are inoculated on the media (YEA) by pour plate method.
    4. Best results are obtained when a practicable range of 80 cfu to 120 cfu per plate with a minimum number of 50 cfu per plate is used.
    5. Incubate at (36 ± 2) °C for (44 ± 4) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Growth.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number NCCB number
    Multi-strain reference material
    RM-AQUA
    		 Enterococcus faecalis 00087 100299
    Escherichia coli 00013 100297
    Pseudomonas fluorescens 100423
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.

  • 2 Quantitative process control with RM-ECO.00013BL

    • Growth. The characteristic reaction of on YEA
    Characteristic reaction: Growth.

    Best Practice

    The single strain RM-ECO.00013BL is used for the enumeration of culturable micro-organisms

    1. Use a quantitative reference material (RM-ECO.00013BL) with a known number of Escherichia coli.
    2. Defrost the material at room temperature for 30 minutes.
    3. Mix well before use and dilute the material so countable numbers are inoculated on the media (YEA) by pour plate method.
    4. Best results are obtained when a practicable range of 80 cfu to 120 cfu per plate with a minimum number of 50 cfu per plate is used.
    5. Incubate at (36 ± 2) °C for (44 ± 4) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Growth.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number
    Single-strain reference material
    RM-ECO.00013BL
    		 Escherichia coli 00013
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.