ISO 15214 (1998) method: Lactic acid bacteria

Process control Food and animal feeding stuffs

Horizontal method for the enumeration of mesophilic lactic acid bacteria - Colony-count technique at 30°C

  • 1 Quantitative process control with CRM-LP

  • Characteristic colonies according to each species. The characteristic reaction of  on MRS
    Characteristic reaction: Characteristic colonies according to each species.

    Best Practice

    The single strain CRM-LP is used for the enumeration of Lactic acid bacteria

    1. Use a quantitative reference material (CRM-LP) with a known number of Lactobacillus plantarum.
    2. Defrost the material at room temperature for 30 minutes.
    3. Mix well before use and dilute the material so countable numbers are inoculated on the media (MRS) by spread plate method.
    4. Best results are obtained when a practicable range of 80 cfu to 120 cfu per plate with a minimum number of 50 cfu per plate is used.
    5. Incubate at (30 ± 1) °C for (72 ± 3) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colonies according to each species.

    Kind of reference material Biosisto product for this control method Control Strain NCCB number
    Single-strain reference material Lactobacillus plantarum 100293
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.
  • 2 Quantitative process control with RM-BLES

  • Characteristic colonies according to each species. The characteristic reaction of  on MRS
    Characteristic reaction: Characteristic colonies according to each species.

    Best Practice

    The multi-strain RM-BLES contains, Bacillus cereus, Lactobacillus plantarum, Escherichia coli WDCM 00013 and Staphylococcus aureus WDCM 00034 in milk. This material can be used for several specific standards. The influence of interfering bacteria is also performed. It is easy to use by making one serie of dilution.

    1. Use a quantitative reference material (RM-BLES) with a known number of Microorganisms.
    2. Defrost the material at room temperature for 30 minutes.
    3. Mix well before use and dilute the material so countable numbers are inoculated on the media (MRS) by spread plate method.
    4. Best results are obtained when a practicable range of 80 cfu to 120 cfu per plate with a minimum number of 50 cfu per plate is used.
    5. Incubate at (30 ± 1) °C for (72 ± 3) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colonies according to each species.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number NCCB number
    Multi-strain reference material Bacillus cereus 100292
    Lactobacillus plantarum 100293
    Escherichia coli serotype O6:H1 00013 100297
    Staphylococcus aureus 00034 100294
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.