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This study reports two novel selective differential media. A first differential medium can be applied in methods for the isolation of non-O157 Shiga toxin-producing Escherichia coli (STEC) serotypes (O26, O103, O111 and O145) from food or faeces. A second differential medium was designed for both sorbitol-positive and -negative O157 STEC strains. Selective differential media are based on a chromogenic compound to signal β-galactosidase activity and one or more fermentative carbon sources. The chromogenic marker and carbohydrates were combined with a pH indicator and several inhibitory components, which resulted in highly specific differentiation media. Consecutive use of a serotype-dependent choice of confirmation media resulted in a very low incidence of false-positive isolates when comparing clinical STEC strains with a collection of commensal E. coli strains. [ABSTRACT FROM AUTHOR]

Microorganisms are intentionally added at different stages of the food and feed chain (food or feed additive, novel food or plant protection product) and are subjected to regulation and safety assessment by the European Food Safety Authority. Safety evaluation is based on application dossiers for market authorisation to the European Commission. The qualified presumption of safety (QPS) concept was developed in 2003 1 to provide a harmonised generic safety pre-appraisal of the above microorganisms. Unambiguously defined biological taxonomic units (TUs) are assessed for their body of knowledge, their safety and their end use. Identified safety concerns for a certain TU can be, where reasonable in number and not universally present, reflected as 'qualifications.' Strains belonging to TUs having QPS status may benefit of a fast track evaluation. The lowest TU for which the QPS status is granted is the species level for bacteria and yeasts and the family for viruses. The QPS concept is also applicable to genetically modified microorganisms used for production purposes. Based on the current body of knowledge and/or the ambiguous taxonomic position, some TUs, such as filamentous fungi, bacteriophages, Enterococcus faecium, Escherichia coli, Streptomyces spp. and Oomycetes, are not considered liable for QPS status. [ABSTRACT FROM AUTHOR]

Microorganisms are intentionally added at different stages of the food and feed chain (food or feed additive, novel food or plant protection product) and are subjected to regulation and safety assessment by the European Food Safety Authority. Safety evaluation is based on application dossiers for market authorisation to the European Commission. The qualified presumption of safety (QPS) concept was developed in 20031 to provide a harmonised generic safety pre-appraisal of the above microorganisms. Unambiguously defined biological taxonomic units (TUs) are assessed for their body of knowledge, their safety and their end use. Identified safety concerns for a certain TU can be, where reasonable in number and not universally present, reflected as 'qualifications.' Strains belonging to TUs having QPS status may benefit of a fast track evaluation. The lowest TU for which the QPS status is granted is the species level for bacteria and yeasts and the family for viruses. The QPS concept is also applicable to genetically modified microorganisms used for production purposes. Based on the current body of knowledge and/or the ambiguous taxonomic position, some TUs, such as filamentous fungi, bacteriophages, Enterococcus faecium, Escherichia coli, Streptomyces spp. and Oomycetes, are not considered liable for QPS status.

A previous multidisciplinary study indicated that gliotoxin-producing Aspergillus fumigatus Fresen. isolates from silage commodities mostly belonged to its variant A. fumigatus var. ellipticus Raper & Fennell. Sequence analysis revealed the presence of a single nucleotide polymorphism at five positions in a fragment of the rodA gene (coding for a hydrophobin rodletA protein) between Aspergillus fumigatus var. fumigatus and Aspergillus fumigatus var. ellipticus. A method was developed to distinguish these two types of isolates based on restriction analysis of this rodA gene fragment using the HinfI restriction enzyme. In addition, in silico analysis of 113 rodA gene fragments retrieved from GenBank was performed and confirmed the suitability of this method. In conclusion, the method developed in this study allows easy distinction between A. fumigatus var. fumigatus and its variant ellipticus. In combination with the earlier developed PCR-restriction fragment length polymorphism method of Staab et al. (2009, J Clin Microbiol 47: 2079), this method is part of a sequencing-independent identification scheme that allows for rapid distinction between similar species/variants within Aspergillus section Fumigati, specifically A. fumigatus, A. fumigatus var. ellipticus, Aspergillus lentulus Balajee & K.A. Marr, Neosartorya pseudofischeri S.W. Peterson and Neosartorya udagawae Y. Horie, Miyaji & Nishim., (© 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

This study reports two novel selective differential media. A first differential medium can be applied in methods for the isolation of non-O157 Shiga toxin-producing Escherichia coli (STEC) serotypes (O26, O103, O111 and O145) from food or faeces. A second differential medium was designed for both sorbitol-positive and -negative O157 STEC strains. Selective differential media are based on a chromogenic compound to signal beta-galactosidase activity and one or more fermentative carbon sources. The chromogenic marker and carbohydrates were combined with a pH indicator and several inhibitory components, which resulted in highly specific differentiation media. Consecutive use of a serotype-dependent choice of confirmation media resulted in a very low incidence of false-positive isolates when comparing clinical STEC strains with a collection of commensal E. coli strains.