Development of a CEN-ISO horizontal standard method
Editor's Note: Another of the presentations follows from last January's 1st International Conference on Cronobacter (Enterobacter Sakazakii) held at University College Dublin. Dr. Han Joosten from the Nestle Research Center in Switzerland addresses the standard method for detection of Cronobacter.
Biography: Dr. Han Joosten is a Senior Scientist at the Nestle Research Center in Lausanne, Switzerland. At Nestle since 1996, he is responsible for providing scientific guidance on various research projects and early identification of emerging microbiological safety issues. He also provides advice to the business and quality management on analytical methods, hurdle technology, safety assessments and HACCP.
After finishing his studies at the University of Nijmegen in the Netherlands in 1983 Joosten worked five years at NIZO Food Research on the formation of biogenic amines in cheese, obtaining his PhD degree from the University of Wageningen on this subject.
From 1989 to 1991 he worked as a postdoc at the Autonomous University of Madrid on molecular characterization of African Swine Fever Virus. After this he headed the microbiological laboratory of Coberco Research in Deventer, the Netherlands and moved back to Spain in 1994 where he worked for two years at the National Instititute for Agricultural and Food Research (CIT-INIA) in Madrid on a bacteriocin-producing Enterococcus strain.
Summary - Development of a CEN-ISO horizontal standard method for detection of Cronobacter
The availability of a reliable and internationally accepted reference method for detection of Cronobacter in powdered infant formula is an essential tool to verify compliance with regulatory requirements by public health authorities and manufacturers. ISO-TS 22964:2006 was developed as a temporary solution for this purpose, but shortly after being issued it was decided to prepare a full-fledged horizontal CEN-ISO standard.
A summary will be given of the work done thus far, in particular with respect to the modifications that are envisaged to address the main shortcomings of TS 22964:
- The scope will be extended to all types of powdered infant formula (incl. soy- based) and infant formula ingredients.
- It will take into account the latest taxonomical revisions (e.g. definition of the genus Cronobacter and phenotypically related species)
- It will no longer use yellow pigment production as a confirmation criterion
- The enrichment broth (mLST) and chromogenic isolation agar (ESIATM) are too selective and need to be replaced by media that will also allow the detection of strains that are very susceptible to commonly used inhibitors of gram positive microorganisms.
- The main performance characteristics of the new standard will be determined
Based on the results obtained during an extensive comparative/collaborative trial a method based on the utilization of Cronobacter Screening Broth (CSB) in combination with modified DFI agar appears to be the most suitable procedure to be adopted in the new standard.
His POWERPOINT can be found here.
