ISO 21871 (2006) method: Bacillus cereus

Process control Food and animal feeding stuffs

Horizontal method for the enumeration of low numbers of presumptive Bacillus cereus - Most probable number technique and detection method

  • 1 Quantitative process control with CRM-BC

  • Best Practice

    The single strain CRM-BC can be used when only vegetative cells are measured

    1. Use a quantitative reference material (CRM-BC) with a known number of Bacillus cereus.
    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 (TSPB) 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 (48 ± 4) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colonies according to each medium (see ISO 21871).

    Kind of reference material Biosisto product for this control method Control Strain NCCB number
    Single-strain reference material Bacillus cereus 100292
    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-BC veg

  • Best Practice

    The single strain RM-BC veg can be used when vegetative cells and or spores are measured

    1. Use a quantitative reference material (RM-BC veg) with a known number of Bacillus cereus.
    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 (TSPB) 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 (48 ± 4) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colonies according to each medium (see ISO 21871).

    Kind of reference material Biosisto product for this control method Control Strain NCCB number
    Single-strain reference material Bacillus cereus 100292
    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-BCE.00001MH

  • Best Practice

    The single strain RM-BCE.00001MH contains Bacillus cereus vegetative cells and heat-resistant spores. This material can be used for vegetative cell analyse and the spore analyse

    1. Use a quantitative reference material (RM-BCE.00001MH) with a known number of Bacillus cereus.
    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 (TSPB) 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 (48 ± 4) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Characteristic colonies according to each medium (see ISO 21871).

    Kind of reference material Biosisto product for this control method Control Strain CCUG number
    Single-strain reference material Bacillus cereus 10781
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.