ISO 6888-1 (1999) method: Coagulasepositive staphylococci

Process control Food and animal feeding stuffs

Horizontal method for the enumeration of coagulase-positive staphylococci (Staphylococcus aureus and other species) - Part 1: Technique using Baird Parker agar medium

  • 1 Quantitative process control with CRM-SA

    • Black or grey colonies with clear halo (egg yolk clearing reaction). The characteristic reaction of on BPA
    Characteristic reaction: Black or grey colonies with clear halo (egg yolk clearing reaction).

    Best Practice

    The single strain CRM-SA is used for the enumeration of Coagulasepositive staphylococci

    1. Use a quantitative reference material (CRM-SA) with a known number of Staphylococcus aureus.
    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 (BPA) 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 (37 ± 1) °C for (24 ± 2) h to (48 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Black or grey colonies with clear halo (egg yolk clearing reaction).

    Kind of reference material Biosisto product for this control method Control Strain WDCM number
    Single-strain reference material
    CRM-SA
    		 Staphylococcus aureus 00034
    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

    • Black or grey colonies with clear halo (egg yolk clearing reaction). The characteristic reaction of on BPA
    Characteristic reaction: Black or grey colonies with clear halo (egg yolk clearing reaction).

    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 (BPA) 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 (37 ± 1) °C for (24 ± 2) h to (48 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Black or grey colonies with clear halo (egg yolk clearing reaction).

    Kind of reference material Biosisto product for this control method Control Strain WDCM number NCCB number
    Multi-strain reference material
    RM-BLES
    		 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.