The QPS system was proposed to harmonize approaches to the safety assessment of microorganisms across the various EFSA scientific panels. The QPS approach is meant to be a fast track for species for which there is a sufficient body of knowledge that all strains within a species are assumed to be safe. This presumption may be qualified by some restrictions such as the absence of specific characteristics (for example the absence of transmissible antibiotic resistance, absence of

food poisoning toxins, absence of surfactant activity, and absence of enterotoxic activity). The QPS list PF2341066 covers only selected groups of microorganisms which have been referred to EFSA for a formal assessment of safety (Anon, 2005 and Leuschner et al., 2010). find more Seventy-nine species of microorganisms have so far been submitted to EFSA for a safety assessment; the list is updated annually (EFSA, 2007, EFSA, 2008, EFSA, 2009 and EFSA, 2010). The absence of a particular organism from the QPS list does not necessarily imply a risk associated with its use. Individual strains may be safe, but this cannot be ascertained from the existing knowledge of the taxonomic unit to which it belongs. Another reason for a species not being on the list could be that EFSA has not been asked to assess the safety of any strains of the

species. A recent review (Herody et al., 2010) gives a thorough description of the European regulatory environment for microbial food cultures. Denmark is the nation with the first national legislation (since 1974) that specifically requires safety approval 4-Aminobutyrate aminotransferase of MFC. More than 80 species used in 14 different food categories have been approved and published at the Danish Veterinary and Food Administration web site (Anon, 2009). In 2010, the regulation was changed. Approval is no longer needed, but a notification of a new species or a new application is still required before it can

be marketed in Denmark. This topic has also recently been investigated by Germany (Vogel et al., 2011). Taxonomy and systematics constitute the basis for the regulatory frameworks for MFCs. It is thus somewhat unfortunate that the definition of microbial species as a taxonomic unit lacks a theoretical basis (Stackebrandt, 2007). For this reason, we briefly outline the current status of bacterial and fungal taxonomy. In the third edition of Prokaryotes (Stackebrandt, 2006), Stackebrandt proposes a prokaryotic species to be defined by: • a phylogenetic component given as “the smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descendents” (Cracraft, 1983), In general, a polyphasic approach to taxonomy is recommended in bacteriology (Vandamme et al., 1996). In practice, this means that a bacterial species is represented by a type strain with strains showing a high degree of phenotypic and/or genotypic similarity to the type strain regarded as belonging to the same species.