Polymerase chain reaction (PCR) for the detection of king bolete (Boletus edulis) and slippery jack (Suillus luteus) in food samples

. Expensive food is always a possible target for fraudulent labelling. King bolete (Boletus edulis) belongs to the most popular and expensive mushrooms in Europe. Polymerase chain reaction (PCR) analysis on the internal transcribed spacer (ITS) is a suitable method of identifying mushroom species. The ITS region of several Boletus edulis and several closely related mushroom species (e.g. Suillus luteus) was sequenced. Using these results specific PCR methods could be established. Furthermore it was shown that a mushroom sold as king bolete originated in China, and is actually another mushroom species. A market survey showed that in highly processed food products with labelling identifying king bolete in fact always contained these Chinese bolete species.     

Performance of the Asterix III high power iodine laser

For more than 500 shots the 1 TW iodine laser Asterix III has demonstrated high reliability for light-plasma-interaction experiments. Improved laser parameters and new measurements of light pulse properties are reported.     

Quantitative detection of the 35S promoter and the NOS terminator using quantitative competitive PCR

 DNA-based analytical methods are often used to verify the presence of genetically modified organisms (GMOs) in food. In Switzerland, a preliminary study, organized by a subcommission of the Swiss Food Manual, of different polymerase chain reaction (PCR) systems for the detection of GMOs showed that the application of qualitative PCR systems can lead to interlaboratory differences of at least a factor of 10. These differences can be diminished using internal standards (competitors). The quantitative competitive (QC) PCR for the detection of the 35S promoter or the NOS terminator in food samples is presented. The GMO content of food samples can be determined using QC-PCR. Received: 2 July 1998 / Revised version: 15 October 1998     

Development of primer and probe sets for the detection of plant species in honey

An objective of workpackage 3 within the European Research Project “TRACE” was the identification of PCR markers for the detection of plant species related to honey. Within the project “Miel de Corse”, a protected designation of origin (PDO) honey and “Miel de Galicia”, a protected geographical indication (PGI) honey as well as German and English honeys were analysed. Beside the development of plant species specific real-time PCR systems a method has been established for the detection of DNA derived from plant species in general.     

Sensitive and semi-quantitative TaqMan™ real-time polymerase chain reaction systems for the detection of beef (Bos taurus) and the detection of the family Mammalia in food and feed

Consumers distrust beef or products that could contain beef because of the BSE (bovine spongiform encephalopathy) and vCJD (variant Creutzfeld Jacob Disease) cases during recent years. Cows could be fed with meat and bone meal-containing food. To regain consumer confidence methods are needed that allow the detection of smallest amounts of beef in the most different kind of products. Polymerase chain reaction (PCR) analysis can be used to detect the smallest amounts of even highly degraded DNA. In this work two methods are presented that allow the detection of mammal DNA and beef DNA, respectively, even in highly degraded DNA. The amplification of fragments as short as 66 and 76 bp, respectively, allow a determination of mammal or beef DNA even in meat and bone meal products.     

Roughness form and waviness measurement by means of light-scattering

This paper deals with a non-contact, optical measuring method which unites the assessment of roughness form and waviness in one single instrument. The     

Identifying unknown game species: experience with nucleotide sequencing of the mitochondrial cytochrome b gene and a subsequent basic local alignment search tool search

 Game meat is often a target for fraudulent labelling. Polymerase chain reaction (PCR) analysis on the mitochondrial cytochrome b sequence with subsequent restriction fragment length polymorphism is the most widely used method of identifying meat species. The lack of reference meat species and the possibility of point mutations affecting the typical restriction pattern of a species sometimes results in an analytical uncertainty. Nowadays, sequencing of the PCR fragment with a subsequent search in an internet-accessible database can avoid these problems. The database search results in a list of sequences in order of the highest percentage of correspondence. In this work it is shown what correspondences within different vertebrate classes, orders, families and species can be expected. Classing with the correct genus is possible, at least for game meat. Received: 20 July 2000 / Revised: 4 October 2000     

Investigation of Iridium Nanoparticles Supported on Sub-stoichiometric Titanium Oxides as Anodic Electrocatalysts in PEM Electrolysis. Part I.: Synthesis and Characterization

Topics in Catalysis - A novel route for obtaining iridium-based electrocatalysts supported on sub-stoichiometric titanium oxides for catalytic applications is presented. Chloride-free titanium...