ISO 16654 (2001) method: Escherichia coli O157

Process control Food and animal feeding stuffs

Horizontal method for the detection of Escherichia coli O157

  • Qualitative process control with RM-EC O.157

  • Transparent colonies with a pale yellowish-brown appearance and a diameter ~1 mm. The characteristic reaction of  on CT-SMAC
    Characteristic reaction: Transparent colonies with a pale yellowish-brown appearance and a diameter ~1 mm.

    Best Practice

    The single strain RM-EC O.157 is used for the detection of Escherichia coli O157

    Process control detection method

    1. Use a quantitative reference material (RM-EC O.157) with a known number of Escherichia coli serotype O157:H7 (non-VTEC).
    2. Defrost the material at room temperature for 30 minutes.
    3. Mix well before use.
    4. In the case of qualitative operations the contamination level of the reference material (RM-EC O.157) must be representative of the limit of detection.
    5. At an average contamination level of 5 cfu per control sample, the probability of using a coincidentally uninfected (negative) sample according to the Poisson spread is less than 1%.
    6. Incubate at (37 ± 1) °C for (21 ± 3) h.
    7. Determine the absence or presence of the microorganism and register your finding in a qualitative control chart.
    8. The characteristic reaction is: Transparent colonies with a pale yellowish-brown appearance and a diameter ~1 mm.

    Kind of reference material Biosisto product for this control method Control Strain WDCM number
    Single-strain reference material Escherichia coli serotype O157:H7 (non-VTEC) 00014
    The Biosisto reference material in this table is used in the best practice for Qualitative process control according ISO 17025.