ISO 10272-1 (2017) medium: Preston broth

Media control Food chain

Microorganisms and performance criteria for selective enrichment media 'Preston broth' used in Food chain microbiology according to ISO 10272-1.

  • 1 Qualitative control of Productivity

    • Best Practice Preston broth

    Qualitative control of Selectivity of liquid medium, mixed culture

    1. Use a quantitative reference material or test suspension with a known number of Campylobacter jejuni and Escherichia coli and Proteus mirabilis.
    2. Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
    3. Incubate at (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h.
    4. Remove 10 µl and streak to a plate of specific medium for the target organism.
    5. Incubate at (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h.
    6. Growth of target microorganisms should reach ">10 characteristic colonies on mCCD agar" with a characteristic reaction of: Greyish, flat and moist, sometimes with metallic sheen.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Campylobacter jejuni
    or
    		(37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h
    microaerobic atmosphere    		 >10 characteristic colonies on mCCD agar Greyish, flat and moist, sometimes with metallic sheen
    + Escherichia coli
    or
    + Proteus mirabilis
    The best practice for Qualitative control of Productivity for media control of 'Preston broth' is based on the data displayed in this table according ISO 10272-1.

  • 2 Qualitative control of Productivity opt

    • Best Practice Preston broth

    Qualitative control of Selectivity of liquid medium, mixed culture

    1. Use a quantitative reference material or test suspension with a known number of Campylobacter coli and Escherichia coli and Proteus mirabilis.
    2. Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
    3. Incubate at (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h.
    4. Remove 10 µl and streak to a plate of specific medium for the target organism.
    5. Incubate at (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h.
    6. Growth of target microorganisms should reach ">10 characteristic colonies on mCCD agar" with a Characteristic reaction of: Greyish, flat and moist, sometimes with metallic sheen.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Campylobacter coli
    		(37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h
    microaerobic atmosphere    		 >10 characteristic colonies on mCCD agar Greyish, flat and moist, sometimes with metallic sheen
    + Escherichia coli
    or
    + Proteus mirabilis
    The best practice for Qualitative control of Productivity for media control of 'Preston broth' is based on the data displayed in this table according ISO 10272-1.

  • Qualitative control of Selectivity

    • Best Practice Preston broth

    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 and Proteus mirabilis.
    2. Inoculate one tube of test medium with >103 cells of non-target organisms.
    3. Incubate at (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h.
    4. Remove 10 µl and streak to a plate of reference medium (TSA).
    5. Incubate at (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) 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 (37 ± 1) °C then (41,5 ± 1) °C for (5 ± 1) h then 44 ± 4) h
    microaerobic atmosphere    		 Total inhibition (0) on TSA No growth
    + Proteus mirabilis
    The best practice for Qualitative control of Selectivity for media control of 'Preston broth' is based on the data displayed in this table according ISO 10272-1.