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Ruf J.,Official Food Control Authority of the Canton of Thurgau Kantonales Laboratorium Thurgau | Walter P.,Official Food Control Authority of the Canton of Thurgau Kantonales Laboratorium Thurgau | Kandler H.,Official Food Control Authority of the Canton of Zurich Kantonales Laboratorium Zurich | Kaufmann A.,Official Food Control Authority of the Canton of Zurich Kantonales Laboratorium Zurich
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed. © 2012 Copyright Taylor and Francis Group, LLC. Source


Kaufmann A.,Official Food Control Authority of the Canton of Zurich Kantonales Laboratorium Zurich | Koppel R.,Official Food Control Authority of the Canton of Zurich Kantonales Laboratorium Zurich | Widmer M.,Official Food Control Authority of the Canton of Zurich Kantonales Laboratorium Zurich
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

Transglutaminase is an enzyme that can be used to cross-link pieces of meat, fish or meat products. The resulting product gives the optical impression of an intact chunk of meat. The usage of transglutaminase as a food additive is permitted in some countries. However, its utilisation has to be declared to ensure transparency for consumers. This paper describes two orthogonal analytical methods suited for the detection of technological relevant transglutaminase concentrations (around 25 mg pure enzyme in 1 kg of product) in meat and meat products. The mass spectrometry-based approach relies on a previous digestion with Achromobacter lyticus protease and LC-MS/MS separation and detection. Sufficient selectivity was obtained by monitoring four different peptides. The orthogonal (complementary and independent), ELISA-based approach relies on two commercially available bacterial transglutaminase-specific antibodies, combined to a sandwich ELISA. The two methods were tested by analysing some 60 samples obtained from the market. © 2012 Copyright Taylor and Francis Group, LLC. Source

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