ISO/ TS 21872-2 (2007) medium: SDS

Media control Food and animal feeding stuffs

Microorganisms and performance criteria for selective isolation media 'SDS' used in Food and animal feeding stuffs microbiology according to ISO 11133.

  • Qualitative control of Productivity

    • Best Practice SDS

    Qualitative control of Productivity solid medium

    1. Use a reference material or test suspension with a known number of Vibrio vulnificus and Vibrio cholerae non-O1/non-O139.
    2. The volume used for testing should contain 103 to 104 cfu for qualitative tests of plate media.
    3. Streak each test microorganism (Vibrio vulnificus and Vibrio cholerae non-O1/non-O139) on the media under test (SDS) to obtain discrete colonies.
    4. Incubate at (37 ± 1) °C for (24 ± 3) 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 (SDS) and standard (ISO/ TS 21872-2) combination the criteria is: "Good growth (2)".
    7. The Characterictic reaction is: Purple/green colonies with an opaque halo.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Vibrio vulnificus
    		(37 ± 1) °C for (24 ± 3) h Good growth (2) Purple/green colonies with an opaque halo
    + Vibrio cholerae non-O1/non-O139
    The best practice for Qualitative control of Productivity for media control of 'SDS' is based on the data displayed in this table according ISO 11133.

  • Qualitative control of Selectivity

    • Best Practice SDS

    Qualitative control of Selectivity solid medium

    1. Use a reference material or test suspension with a known number of Escherichia coli.
    2. Streak the test strain (Escherichia coli) as a single line on the media under test (SDS).
    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 (37 ± 1) °C for (24 ± 3) 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 (SDS) and standard (ISO/ TS 21872-2) combination the criteria is: "Total inhibition (0).

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Escherichia coli
    or
    or
    		(37 ± 1) °C for (24 ± 3) h Total inhibition (0) No growth
    The best practice for Qualitative control of Selectivity for media control of 'SDS' is based on the data displayed in this table according ISO 11133.