Validation of standard method EN ISO 22964:2017 - Microbiology of the food chain - Horizontal method for the detection of Cronobacter spp

Autor: David Tomas, Isabelle Desforges, Begoña Ruiz, Barbara Gerten, Amparo de Benito, Nathalie Gnanou Besse
Rok vydání: 2017
Předmět:
Zdroj: International journal of food microbiology. 288
ISSN: 1879-3460
Popis: The new version of the ISO standard method for detection of Cronobacter spp. (EN ISO 22964:2017) was validated in the frame of the European Commission Mandate M381 to CEN. Seventeen laboratories from nine countries participated in the interlaboratory studies to determine the performance characteristics of the method. The performance of the method was evaluated using matrices for which the presence of Cronobacter spp. is considered to be of serious concern, such as infant formula and its ingredients and representatives of categories cited in the EC Regulation 2073/2005 on microbiological criteria for foodstuffs for Cronobacter spp. The five matrices included in the validation were: two types of powdered infant food formulas (with and without probiotics); lactose; starch and environmental samples (swabs). The samples were each tested at two different levels of contamination, plus a negative control. Inoculation levels ranged from 4 to 95 CFU/sample. Each participant examined eight replicates of each level of inoculation, a total of 24 samples per matrix type. Specificity was calculated for each matrix used in the validation, with results ranging between 99 and 100%. Sensitivity of the method was calculated for samples in which no fractional recovery was expected and the values that were obtained ranged between 65 and 100%, depending on the matrix, the inoculation level and the interfering microbiota present in the samples. LOD50 value was calculated for three food items (the two powdered infant formulas and the starch) with values between 0.8 and 1.1 CFU/sample.
Databáze: OpenAIRE