ISO 16649-3 (2016) medium: MMG

Media control Food chain

Microorganisms and performance criteria for selective enrichment media 'MMG' used in Food chain microbiology according to ISO 11133.

  • Qualitative control of Productivity

  • Best Practice MMG

    Qualitative single tube method for performance testing of liquid media – pre-enrichment media

    1. Use a reference material or test suspension with a known number of Escherichia coli.
    2. Inoculate the media (MMG) with 0.1 mL of more than 100 cfu/mL and less then 1000 cfu/mL of microorganisms.
    3. Incubate at (37 ± 1) °C for (24 ± 2) h.
    4. Asses the amount of growth as, 0 for no turbidity, 1 for slight turbidity or 2 for good turbidity.
    5. For this medium (MMG) and standard (ISO 16649-3) combination the criteria is: "Acid production."

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Escherichia coli (37 ± 1) °C for (24 ± 2) h Acid production Colour change to yellow
    The best practice for Qualitative control of Productivity for media control of 'MMG' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Selectivity

  • Best Practice MMG

    Qualitative control of Selectivity of liquid medium, single culture

    1. Use a quantitative reference material or test suspension with a known number of Enterococcus faecalis.
    2. Inoculate one tube of test medium with >103 cells of non-target organisms.
    3. Incubate at (37 ± 1) °C for (24 ± 2) h.
    4. Remove 10 µl and streak to a plate of reference medium (TSA).
    5. Incubate at (37 ± 1) °C for (24 ± 2) h.
    6. Growth of non-target microorganisms should comply with the criteria: "Total inhibition on TSA (0)".

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterococcus faecalis or TSA (37 ± 1) °C for (24 ± 2) h Total inhibition on TSA (0) No growth
    The best practice for Qualitative control of Selectivity for media control of 'MMG' is based on the data displayed in this table according ISO 11133.