ISO 11290-1 (2017) method: Listeria monocytogenes

Process control Food chain

Horizontal method for the detection and enumeration of Listeria monocytogenes and of Listeria spp. - Part 1: Detection method

  • Qualitative process control with CRM-LM

  • Blue green colonies with opaque halo. The characteristic reaction of  on ALOA
    Characteristic reaction: Blue green colonies with opaque halo.

    Best Practice

    Single strain te be used for the detection of Listeria monocytogenes and of Listeria spp.

    Process control detection method

    1. Use a quantitative reference material (CRM-LM) with a known number of Listeria monocytogenes.
    2. Defrost the material at room temperature for 30 minutes.
    3. Mix well before use.
    4. In the case of qualitative operations the contamination level of the reference material (CRM-LM) must be representative of the limit of detection.
    5. At an average contamination level of 5 cfu per control sample, the probability of using a coincidentally uninfected (negative) sample according to the Poisson spread is less than 1%.
    6. Incubate at (37 ± 1) °C for (48 ± 4) h.
    7. Determine the absence or presence of the microorganism and register your finding in a qualitative control chart.
    8. The characteristic reaction is: Blue green colonies with opaque halo.

    Kind of reference material Biosisto product for this control method Control Strain NCCB number
    Single-strain reference material Listeria monocytogenes 100286
    The Biosisto reference material in this table is used in the best practice for Qualitative process control according ISO 17025.