ISO 11290-1 (2017) medium: Half-Fraser

Media control Food chain

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

  • 1 Qualitative control of Productivity

  • Best Practice Half-Fraser

    Qualitative control of Selectivity of liquid medium, mixed culture

    1. Use a quantitative reference material or test suspension with a known number of Listeria monocytogenes 4b and Escherichia coli and Enterococcus faecalis.
    2. Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
    3. Incubate at (30 ± 1) °C for (24 ± 2) h.
    4. Remove 10 µl and streak to a plate of specific medium for the target organism.
    5. Incubate at (30 ± 1) °C for (24 ± 2) h.
    6. Growth of target microorganisms should reach "> 10 colonies on Agar Listeria according to Ottaviani and Agosti" with a characteristic reaction of: Blue green colonies with opaque halo.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Listeria monocytogenes 4b (30 ± 1) °C for (24 ± 2) h > 10 colonies on Agar Listeria according to Ottaviani and Agosti Blue green colonies with opaque halo
    + Escherichia coli or
    + Enterococcus faecalis or
    The best practice for Qualitative control of Productivity for media control of 'Half-Fraser' is based on the data displayed in this table according ISO 11133.
  • 2 Qualitative control of Productivity opt

  • Best Practice Half-Fraser

    Qualitative control of Selectivity of liquid medium, mixed culture

    1. Use a quantitative reference material or test suspension with a known number of Listeria monocytogenes 1/2a and Escherichia coli and Enterococcus faecalis.
    2. Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
    3. Incubate at (30 ± 1) °C for (24 ± 2) h.
    4. Remove 10 µl and streak to a plate of specific medium for the target organism.
    5. Incubate at (30 ± 1) °C for (24 ± 2) h.
    6. Growth of target microorganisms should reach "> 10 colonies on Agar Listeria according to Ottaviani and Agosti" with a Characteristic reaction of: Blue green colonies with opaque halo.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Listeria monocytogenes 1/2a (30 ± 1) °C for (24 ± 2) h > 10 colonies on Agar Listeria according to Ottaviani and Agosti Blue green colonies with opaque halo
    + Escherichia coli or
    + Enterococcus faecalis or
    The best practice for Qualitative control of Productivity for media control of 'Half-Fraser' is based on the data displayed in this table according ISO 11133.
  • 1 Qualitative control of Selectivity man

  • Best Practice Half-Fraser

    Qualitative control of Selectivity of liquid medium, single culture

    1. Use a quantitative reference material or test suspension with a known number of Escherichia coli.
    2. Inoculate one tube of test medium with >103 cells of non-target organisms.
    3. Incubate at (30 ± 1) °C for (24 ± 2) h.
    4. Remove 10 µl and streak to a plate of reference medium (TSA).
    5. Incubate at (30 ± 1) °C for (24 ± 2) h.
    6. Growth of non-target microorganisms should comply with the criteria: "Total inhibition (0) on TSA".

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Escherichia coli or TSA (30 ± 1) °C for (24 ± 2) h Total inhibition (0) on TSA No growth
    The best practice for Qualitative control of Selectivity for media control of 'Half-Fraser' is based on the data displayed in this table according ISO 11133.
  • 2 Qualitative control of Selectivity man

  • Best Practice Half-Fraser

    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 (30 ± 1) °C for (24 ± 2) h.
    4. Remove 10 µl and streak to a plate of reference medium (TSA).
    5. Incubate at (30 ± 1) °C for (24 ± 2) h.
    6. Growth of non-target microorganisms should comply with the criteria: "< 100 colonies on TSA".

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterococcus faecalis or TSA (30 ± 1) °C for (24 ± 2) h < 100 colonies on TSA Growth
    The best practice for Qualitative control of Selectivity for media control of 'Half-Fraser' is based on the data displayed in this table according ISO 11133.