ISO 4832 (2006) method: Coliforms

Process control Food and animal feeding stuffs

Horizontal method for the enumeration of Coliforms - Colony-count technique

  • 1 Quantitative process control with RM-CFREU

    • Purplish-red colonies with or without precipitation halo. The characteristic reaction of on VRBL
    Characteristic reaction: Purplish-red colonies with or without precipitation halo.

    Best Practice

    The single strain RM-CFREU is used for the enumeration of Enterobacteriaceae

    1. Use a quantitative reference material (RM-CFREU) with a known number of Citrobacter freundii.
    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 (VRBL) by pour 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 (24 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Purplish-red colonies with or without precipitation halo.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number
    Single-strain reference material
    RM-CFREU
    		 Citrobacter freundii 00006
    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-EC

    • Purplish-red colonies with or without precipitation halo. The characteristic reaction of on VRBL
    Characteristic reaction: Purplish-red colonies with or without precipitation halo.

    Best Practice

    The single strain RM-EC is used for the enumeration of coliforms

    1. Use a quantitative reference material (RM-EC) with a known number of Escherichia coli serotype O6:H1.
    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 (VRBL) by pour 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 (24 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Purplish-red colonies with or without precipitation halo.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number
    Single-strain reference material
    RM-EC
    		 Escherichia coli serotype O6:H1 00013
    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-ECO.00012MM

    • Purplish-red colonies with or without precipitation halo. The characteristic reaction of on VRBL
    Characteristic reaction: Purplish-red colonies with or without precipitation halo.

    Best Practice

    The single strain RM-ECO.00012MM is used for the detection and enumeration of coliforms

    1. Use a quantitative reference material (RM-ECO.00012MM) with a known number of Escherichia coli.
    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 (VRBL) by pour 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 (24 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Purplish-red colonies with or without precipitation halo.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number NCCB number
    Single-strain reference material
    RM-ECO.00012MM
    		 Escherichia coli 00012 72002
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.

  • 4 Quantitative process control with RM-ECO.00012BH

    • Purplish-red colonies with or without precipitation halo. The characteristic reaction of on VRBL
    Characteristic reaction: Purplish-red colonies with or without precipitation halo.

    Best Practice

    The single strain RM-ECO.00012BH is used for the enumeration of Coliformen

    1. Use a quantitative reference material (RM-ECO.00012BH) with a known number of Escherichia coli.
    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 (VRBL) by pour 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 (30 ± 1) °C.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Purplish-red colonies with or without precipitation halo.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number NCCB number
    Single-strain reference material
    RM-ECO.00012BH
    		 Escherichia coli 00012 72002
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.

  • 5 Quantitative process control with RM-ECO.00013BL

    • Purplish-red colonies with or without precipitation halo. The characteristic reaction of on VRBL
    Characteristic reaction: Purplish-red colonies with or without precipitation halo.

    Best Practice

    The single strain RM-ECO.00013BL is used for the enumeration of Coliformen

    1. Use a quantitative reference material (RM-ECO.00013BL) with a known number of Escherichia coli serotype O6:H1.
    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 (VRBL) by pour 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 (24 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Purplish-red colonies with or without precipitation halo.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number
    Single-strain reference material
    RM-ECO.00013BL
    		 Escherichia coli serotype O6:H1 00013
    The Biosisto reference material in this table is used in the best practice for Quantitative process control according ISO 17025.

  • 6 Quantitative process control with RM-BLES

    • Purplish-red colonies with or without precipitation halo. The characteristic reaction of on VRBL
    Characteristic reaction: Purplish-red colonies with or without precipitation halo.

    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 (VRBL) by pour 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 (24 ± 2) h.
    6. Count the colony forming units and register in a control chart.
    7. The characteristic reaction is: Purplish-red colonies with or without precipitation halo.

    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.