ISO 9308-1 (2014) medium: CCA

Media control Water quality 

Microorganisms and performance criteria for testing selective media 'CCA' for Enumeration of Escherichia coli en coliformen used in Water quality  microbiology by comparing with a non-selective reference medium according to ISO 9308-1.

  • 1 Quantitative control of Productivity man

    • Darkblue to violet colonies. The characteristic reaction of on CCA
    The characteristic reaction of Escherichia coli on CCA: Darkblue to violet colonies.

    Best Practice CCA

    Quantitative control of Productivity solid medium

    1. Use a quantitative reference material or test suspension with a known number of Escherichia coli.
    2. Dilute this material so 50 to 120 cfu is inoculated on the CCA by membrane filtration method.
    3. Place the membrane on the surface of the agar under test (CCA).
    4. Do this also for the reference media (TSA).
    5. Incubate at (36 ± 2) °C for (21 to 24) h.
    6. Count the colonies on the medium under test (CCA) and the reference media (TSA).
    7. Calculate the productivity ratio PR. The criteria is: PR ≥ 0,7.
    8. If the PR exceeds 1,4 identify the reason.
    9. For this the total count of colonies obtained on the culture medium under test (CCA) is divided by the total count of colonies obtained on the defined reference medium (TSA).
    Calculate the productivity ratio PR as follows: PR  NS
    N0
    Ns = total count test medium
    N0 = total count reference medium

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Escherichia coli
    or
    		TSA (36 ± 2) °C for (21 to 24) h PR ≥ 0,7 Darkblue to violet colonies
    The best practice for Quantitative control of Productivity for media control of 'CCA' is based on the data displayed in this table according ISO 9308-1.

  • 2 Quantitative control of Productivity man

    • Pink to red colonies. The characteristic reaction of on CCA
    The characteristic reaction of Citrobacter freundii on CCA: Pink to red colonies.

    Best Practice CCA

    Quantitative control of Productivity solid medium

    1. Use a quantitative reference material or test suspension with a known number of Citrobacter freundii.
    2. Dilute this material so 50 to 120 cfu is inoculated on the CCA by membrane filtration method for example 0.1 mL suspension.
    3. Place the membrane on the surface of the agar under test (CCA).
    4. Do this also for the reference media (TSA).
    5. Incubate at (36 ± 2) °C for (21 to 24) h.
    6. Count the colonies on the medium under test (CCA) and the reference media (TSA).
    7. Calculate the productivity ratio PR. The criteria is PR ≥ 0,7.
    8. If the PR exceeds 1,4 identify the reason.
    9. For this the total count of colonies obtained on the culture medium under test (CCA) is divided by the total count of colonies obtained on the defined reference medium (TSA).
    Calculate the productivity ratio PR as follows: PR  NS
    N0
    Ns = total count test medium
    N0 = total count reference medium

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Citrobacter freundii
    		TSA (36 ± 2) °C for (21 to 24) h PR ≥ 0,7 Pink to red colonies
    The best practice for Quantitative control of Productivity for media control of 'CCA' is based on the data displayed in this table according ISO 9308-1.

  • 3 Quantitative control of Productivity man

    • Best Practice CCA

    Quantitative control of Productivity solid medium

    1. Use a quantitative reference material or test suspension with a known number of Enterobacter aerogenes.
    2. Dilute this material so 50 to 120 cfu is inoculated on the CCA by membrane filtration method for example 0.1 mL suspension.
    3. Place the membrane on the surface of the agar under test (CCA).
    4. Do this also for the reference media (TSA).
    5. Incubate at (36 ± 2) °C for (21 to 24) h.
    6. Count the colonies on the medium under test (CCA) and the reference media (TSA).
    7. Calculate the productivity ratio PR. The criteria is PR ≥ 0,7.
    8. If the PR exceeds 1,4 identify the reason.
    9. For this the total count of colonies obtained on the culture medium under test (CCA) is divided by the total count of colonies obtained on the defined reference medium (TSA).
    Calculate the productivity ratio PR as follows: PR  NS
    N0
    Ns = total count test medium
    N0 = total count reference medium

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterobacter aerogenes
    00175 opt
    		 TSA (36 ± 2) °C for (21 to 24) h PR ≥ 0,7 Pink to red colonies
    The best practice for Quantitative control of Productivity for media control of 'CCA' is based on the data displayed in this table according ISO 9308-1.

  • Qualitative control of Selectivity

    • Best Practice CCA

    Qualitative control of Selectivity solid medium

    1. Use a reference material or test suspension with a known number of Enterococcus faecalis.
    2. Streak the test strain (Enterococcus faecalis) as a single line on the media under test (CCA).
    3. Use a 1 µl loop in case of a concentration of at least 10000 cfu or a 10 µl loop in case of a concentration between 1000 and 10000 cfu.
    4. Incubate at (36 ± 2) °C for (21 to 24) h.
    5. Asses the amount of growth as, 0 for no growth, 1 for weak growth or 2 for good growth.
    6. For this medium (CCA) and standard (ISO 9308-1) combination the criteria is: "Total or partial inhibition.

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterococcus faecalis
    or
    		(36 ± 2) °C for (21 to 24) h Total or partial inhibition No growth
    The best practice for Qualitative control of Selectivity for media control of 'CCA' is based on the data displayed in this table according ISO 9308-1.

  • Qualitative control of Specificity

    • Best Practice CCA

    Qualitative control of Specificity solid medium

    1. Use a reference material or test suspension with a known number of Pseudomonas aeruginosa.
    2. Streak the test controlstrain (Pseudomonas aeruginosa) on the media under test (CCA) to obtain discrete colonies.
    3. Use a 1 µl loop in case of a concentration of at least 1000 cfu/mL.
    4. Incubate at (36 ± 2) °C for (21 to 24) h.
    5. Asses the presence, absence and/or grade of expression of biochemical responses and colony sizes and morphology.
    6. For this medium (CCA) and standard (ISO 9308-1) combination the characteristic reaction is: Colourless colonies.

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Pseudomonas aeruginosa
    		(36 ± 2) °C for (21 to 24) h Growth Colourless colonies
    The best practice for Qualitative control of Specificity for media control of 'CCA' is based on the data displayed in this table according ISO 9308-1.