ISO 11290-1 (2017) medium: ALOA

Media control Food chain

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

  • Qualitative control of Productivity

  • Best Practice ALOA

    Qualitative control of Productivity solid medium

    1. Use a reference material or test suspension with a known number of Listeria monocytogenes 4b.
    2. The volume used for testing should contain 103 to 104 cfu for qualitative tests of plate media.
    3. Streak the test microorganism (Listeria monocytogenes 4b) on the media under test (ALOA) to obtain discrete colonies.
    4. Incubate at (37 ± 1) °C for (48 ± 4) 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 (ALOA) and standard (ISO 11290-1) combination the criteria is: "Good growth (2)".
    7. The Characterictic reaction is: Blue green colonies with opaque halo.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Listeria monocytogenes 4b (37 ± 1) °C for (48 ± 4) h Good growth (2) Blue green colonies with opaque halo
    Listeria monocytogenes 1/2a
    The best practice for Qualitative control of Productivity for media control of 'ALOA' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Selectivity

  • Best Practice ALOA

    Qualitative control of Selectivity solid medium

    1. Use a reference material or test suspension with a known number of Escherichia coli and Enterococcus faecalis.
    2. Streak the test strain (Escherichia coli and Enterococcus faecalis) as a single line on the media under test (ALOA).
    3. Multiple strains can be streaked on the plate as long no crossing occurs.
    4. 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.
    5. Incubate at (37 ± 1) °C for (48 ± 4) h.
    6. Asses the amount of growth as, 0 for no growth, 1 for weak growth or 2 for good growth.
    7. For this medium (ALOA) and standard (ISO 11290-1) combination the criteria is: "Total inhibition (0).

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Escherichia coli or (37 ± 1) °C for (48 ± 4) h Total inhibition (0) No Growth
    + Enterococcus faecalis or
    The best practice for Qualitative control of Selectivity for media control of 'ALOA' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Specificity

  • Best Practice ALOA

    Qualitative control of Specificity solid medium

    1. Use a reference material or test suspension with a known number of Listeria innocua.
    2. Streak the test controlstrain (Listeria innocua) on the media under test (ALOA) to obtain discrete colonies.
    3. Use a 1 µl loop in case of a concentration of at least 1000 cfu/mL.
    4. Incubate at (37 ± 1) °C for (48 ± 4) h.
    5. Asses the presence, absence and/or grade of expression of biochemical responses and colony sizes and morphology.
    6. For this medium (ALOA) and standard (ISO 11290-1) combination the characteristic reaction is: Blue green colonies without opaque halo.

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Listeria innocua (37 ± 1) °C for (48 ± 4) h Growth Blue green colonies without opaque halo
    The best practice for Qualitative control of Specificity for media control of 'ALOA' is based on the data displayed in this table according ISO 11133.