Cronobacter Support
05-12-2009, 07:14 PM
1st International Conference on Cronobacter Poster Abstract 29
Evaluation of the ISO/IDF draft standard method for the detection of Enterobacter sakazakii in milk powder products and powder infant formulas
Enterobacter sakazakii is the causative agent of rare but severe neonatal infections, linked to the consumption of contaminated powdered infant food formulas. As a result of the growing recognition of E. sakazakii as an emergent pathogen, the International Dairy Federation (IDF) and the International Standard Organisation (ISO) have standardized a reference method project for its detection in infant food formulas factories products and environmental samples. The objectives of this study were to assess the applicability of the ISO/IDF draft standard, and to compare several chromogenic selective media for E. sakazakii. We evaluated three chromogenic media based on a-glucoside activity, i.e. ESIA™ (AES Laboratoires), DFI™ (Oxoid) and COMPASS™ (Biokar diagnostics) and a selective medium for Enterobacteriaceae, VRBG (AES Laboratoires). Thirty-eight suspected naturally contaminated samples from infant formulae factories were analysed, and also twenty-eight E. sakazakii strains and sixteen other Enterobacteriaceae strains were tested. We showed that the ISO/IDF method is sensitive, selective and applicable to the analysis of powder infant food formula but may still be improved. (i) Observation of yellow pigmentation for suspected E. sakazakii colonies on tryptone soy agar (TSA) at 25°C should be excluded. (ii) Another chromogenic agar than the one prescribed (ESIA) in the ISO/IDF method can be successfully used for the isolation of E. sakazakii.
Véronique Deperrois, Sylviane Derzelle, Véronique Maladen, Nicole Soudrie and Nathalie Gnanou-Besse
Unité Composition et Hygiène des Produits Alimentaires, Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d ’Etudes et de Recherches sur la Qualité des Aliments et des Procédés agro-alimentaires.
Evaluation of the ISO/IDF draft standard method for the detection of Enterobacter sakazakii in milk powder products and powder infant formulas
Enterobacter sakazakii is the causative agent of rare but severe neonatal infections, linked to the consumption of contaminated powdered infant food formulas. As a result of the growing recognition of E. sakazakii as an emergent pathogen, the International Dairy Federation (IDF) and the International Standard Organisation (ISO) have standardized a reference method project for its detection in infant food formulas factories products and environmental samples. The objectives of this study were to assess the applicability of the ISO/IDF draft standard, and to compare several chromogenic selective media for E. sakazakii. We evaluated three chromogenic media based on a-glucoside activity, i.e. ESIA™ (AES Laboratoires), DFI™ (Oxoid) and COMPASS™ (Biokar diagnostics) and a selective medium for Enterobacteriaceae, VRBG (AES Laboratoires). Thirty-eight suspected naturally contaminated samples from infant formulae factories were analysed, and also twenty-eight E. sakazakii strains and sixteen other Enterobacteriaceae strains were tested. We showed that the ISO/IDF method is sensitive, selective and applicable to the analysis of powder infant food formula but may still be improved. (i) Observation of yellow pigmentation for suspected E. sakazakii colonies on tryptone soy agar (TSA) at 25°C should be excluded. (ii) Another chromogenic agar than the one prescribed (ESIA) in the ISO/IDF method can be successfully used for the isolation of E. sakazakii.
Véronique Deperrois, Sylviane Derzelle, Véronique Maladen, Nicole Soudrie and Nathalie Gnanou-Besse
Unité Composition et Hygiène des Produits Alimentaires, Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d ’Etudes et de Recherches sur la Qualité des Aliments et des Procédés agro-alimentaires.