ISO 10273 (2017) medium: PSB

Media control Food chain

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

  • 1 Qualitative control of Productivity

  • Best Practice PSB

    Qualitative control of Selectivity of liquid medium, mixed culture

    1. Use a quantitative reference material or test suspension with a known number of Yersinia enterocolitica and Escherichia coli and Pseudomonas aeruginosa.
    2. Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
    3. Incubate at (25 ± 1) °C for 3 to 5 days.
    4. Remove 10 µl and streak to a plate of specific medium for the target organism.
    5. Incubate at (25 ± 1) °C for 3 to 5 days.
    6. Growth of target microorganisms should reach "> 10 colonies on CIN or SSDC" with a characteristic reaction of: Characteristic colonies according to each medium (see ISO 10273).

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Yersinia enterocolitica (25 ± 1) °C for 3 to 5 days > 10 colonies on CIN or SSDC Characteristic colonies according to each medium (see ISO 10273)
    + Escherichia coli or
    + Pseudomonas aeruginosa
    The best practice for Qualitative control of Productivity for media control of 'PSB' is based on the data displayed in this table according ISO 11133.
  • 2 Qualitative control of Productivity opt

  • Best Practice PSB

    Qualitative control of Selectivity of liquid medium, mixed culture

    1. Use a quantitative reference material or test suspension with a known number of Yersinia enterocolitica and Escherichia coli and Pseudomonas aeruginosa.
    2. Inoculate one tube of test medium with < 100 cells of target microorganisms and with >103 cells of non-target organisms.
    3. Incubate at (25 ± 1) °C for 3 to 5 days.
    4. Remove 10 µl and streak to a plate of specific medium for the target organism.
    5. Incubate at (25 ± 1) °C for 3 to 5 days.
    6. Growth of target microorganisms should reach "> 10 colonies on CIN or SSDC" with a Characteristic reaction of: Characteristic colonies according to each medium (see ISO 10273).

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Yersinia enterocolitica (25 ± 1) °C for 3 to 5 days > 10 colonies on CIN or SSDC Characteristic colonies according to each medium (see ISO 10273)
    + Escherichia coli or
    + Pseudomonas aeruginosa
    The best practice for Qualitative control of Productivity for media control of 'PSB' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Selectivity

  • Best Practice PSB

    Qualitative control of Selectivity of liquid medium, single culture

    1. Use a quantitative reference material or test suspension with a known number of Pseudomonas aeruginosa.
    2. Inoculate one tube of test medium with >103 cells of non-target organisms.
    3. Incubate at (25 ± 1) °C for 3 to 5 days.
    4. Remove 10 µl and streak to a plate of reference medium (TSA).
    5. Incubate at (25 ± 1) °C for 3 to 5 days.
    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
    Pseudomonas aeruginosa TSA (25 ± 1) °C for 3 to 5 days Total inhibition (0) on TSA No growth
    Proteus mirabilis
    The best practice for Qualitative control of Selectivity for media control of 'PSB' is based on the data displayed in this table according ISO 11133.