ISO 16649-3 (2016) medium: TBX

Media control Food chain

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

  • Qualitative control of Productivity

  • Best Practice TBX

    Qualitative control of Productivity solid medium

    1. Use a reference material or test suspension with a known number of Escherichia coli.
    2. The volume used for testing should contain 103 to 104 cfu for qualitative tests of plate media.
    3. Streak the test microorganism (Escherichia coli) on the media under test (TBX) to obtain discrete colonies.
    4. Incubate at (44 ± 1) °C for (21 ± 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 (TBX) and standard (ISO 16649-3) combination the criteria is: "Good growth (2)".
    7. The Characterictic reaction is: Blue colonies.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Escherichia coli (44 ± 1) °C for (21 ± 3) h Good growth (2) Blue colonies
    The best practice for Qualitative control of Productivity for media control of 'TBX' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Selectivity

  • Best Practice TBX

    Qualitative control of Selectivity solid medium

    1. Use a reference material or test suspension with a known number of Enterococcus faecalis.
    2. Streak the test strain (Enterococcus faecalis) as a single line on the media under test (TBX).
    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 (44 ± 1) °C for (21 ± 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 (TBX) and standard (ISO 16649-3) combination the criteria is: "Total inhibition (0).

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterococcus faecalis or (44 ± 1) °C for (21 ± 3) h Total inhibition (0) No growth
    The best practice for Qualitative control of Selectivity for media control of 'TBX' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Specificity

  • Best Practice TBX

    Qualitative control of Specificity solid medium

    1. Use a reference material or test suspension with a known number of Citrobacter freundii.
    2. Streak the test controlstrain (Citrobacter freundii) on the media under test (TBX) to obtain discrete colonies.
    3. Use a 1 µl loop in case of a concentration of at least 1000 cfu/mL.
    4. Incubate at (44 ± 1) °C for (21 ± 3) h.
    5. Asses the presence, absence and/or grade of expression of biochemical responses and colony sizes and morphology.
    6. For this medium (TBX) and standard (ISO 16649-3) combination the characteristic reaction is: White to green-beige colonies.

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Citrobacter freundii (44 ± 1) °C for (21 ± 3) h No Growth White to green-beige colonies
    Pseudomonas aeruginosa
    The best practice for Qualitative control of Specificity for media control of 'TBX' is based on the data displayed in this table according ISO 11133.