ISO 21528 (2017) medium: Nutrient agar

Media control Food chain

Microorganisms and performance criteria for non-selective isolation media 'Nutrient agar' used in Food chain microbiology according to ISO 21528.

  • Qualitative control of Productivity

    • Best Practice Nutrient agar

    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 (Nutrient agar) to obtain discrete colonies.
    4. Incubate at (37 ± 1) °C for (24 ± 2) 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 (Nutrient agar) and standard (ISO 21528) combination the criteria is: "Good growth (2)".
    7. The Characterictic reaction is: Growth.

    Control strain WDCM number Incubation Criteria Characteristic reaction
    Escherichia coli
    00013 opt
    		 (37 ± 1) °C for (24 ± 2) h Good growth (2) Growth
    The best practice for Qualitative control of Productivity for media control of 'Nutrient agar' is based on the data displayed in this table according ISO 21528.