ISO 21527-1 (2008) method: Yeasts and moulds

Process control Food and animal feeding stuffs

Horizontal method for the enumeration of yeasts and moulds - Part 1: Colony count technique in products with water activity greater than 0,95

  • 1 Quantitative process control with CRM-PAU

  • Characteristic colony/propagules according to each species. The characteristic reaction of  on DRBC
    Characteristic reaction: Characteristic colony/propagules according to each species.

    Best Practice

    The single strain CRM-PAU, contains a mould, is used for the enumeration of Yeasts and moulds

    1. Use a quantitative reference material (CRM-PAU) with a known number of Penicillium aurantiogriseum.
    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 (DRBC) 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 (25 ± 1) °C for 5 days.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colony/propagules according to each species.

    Kind of reference material Biosisto product for this control method Control Strain
    Single-strain reference material Penicillium aurantiogriseum
    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-PAUYL

  • Characteristic colony/propagules according to each species. The characteristic reaction of  on DRBC
    Characteristic reaction: Characteristic colony/propagules according to each species.

    Best Practice

    The multi strain RM-PAUYL, contains a mould and a yeast, is used for the enumeration of Yeasts and moulds. The material can be used simultaneously as process control for ISO 21527-1 enumeration of yeasts and moulds.

    1. Use a quantitative reference material (RM-PAUYL) 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 (DRBC) 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 (25 ± 1) °C for 5 days.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colony/propagules according to each species.

    Kind of reference material Biosisto product for this control method Control Strain CBS number
    Multi-strain reference material Penicillium aurantiogriseum 792.95
    Yarrowia lipolytica 11385
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.
  • 3 Quantitative process control with RM-YL

  • Characteristic colony/propagules according to each species. The characteristic reaction of  on DRBC
    Characteristic reaction: Characteristic colony/propagules according to each species.

    Best Practice

    The single strain RM-YL, contains a yeast, is used for the enumeration of Yeasts and moulds

    1. Use a quantitative reference material (RM-YL) with a known number of Yarrowia lipolytica.
    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 (DRBC) 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 (25 ± 1) °C for 5 days.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colony/propagules according to each species.

    Kind of reference material Biosisto product for this control method Control Strain CBS number
    Single-strain reference material Yarrowia lipolytica 11385
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.