Fatty acid methyl and ethyl esters as well as wax esters for evaluating the quality of olive oils

Erworben im Rahmen der Schweizer Nationallizenzen (http://www.nationallizenzen.ch)A promising correlation between chemical analysis and sensorial evaluation was confirmed: extra virgin olive oils with low contents of methyl and ethyl esters of fatty acids as well as straight chain wax esters were sensorially evaluated as being of high quality, whereas some with high contents were even devaluated as not being of extra virgin quality. Methanol and ethanol formed during fermentation in degrading olives are esterified, largely by transesterification with fatty acids from the triglycerides, and in this way transferred into the pressed oil. The presence of high contents of methyl and ethyl esters in degrading olives was confirmed. Wax esters from the skin of the olives are extracted at low yields, whereby the yield increases when the olives are soft and possibly degrading. High wax ester contents may, therefore, stand for mild oils, but also for deficient oils

A Personal Review on 40 Years at the Kantonales Labor Zurich: Success – Failure – Conclusions

My career at the Kantonales Labor Zürich (KLZH) started with the introduction of capillary gas chromatography (GC) and took me through an ideal curriculum: first the elaboration of a solid technical background, then a broad range of applications covering all stages from the development of smart and solid methods, understanding the background of a matter and searching for solutions and risk assessment, lobbying to get solutions implemented, sometimes even writing legislation. Selected milestones are described with how the subject came up, what we did and a critical review of the success we had. This gave ample opportunity to think about consumer protection, efficiency in control and performance of authorities. It was a highly motivating job, but sometimes also frustrating because of the weak position of the authorities in defending public interests against big industry. Authorities should be respected, which primarily means competence, strict implementation of relevant rules and insistence if necessary. Often this has little to do with the number or samples analyzed – on the contrary: high sample throughput often prevents us going into depth. In all, what the food safety authorities are capable of implementing is far from that promised to the consumers by legislation

Comprehensive on-line HPLC-GC for screening potential migrants from polypropylene into food: The effect of pulsed light decontamination as an example

High performance liquid chromatography (HPLC) was used for the fractionation of extracts from polypropylene (PP) films and coupled on-line to gas chromatography (GC) with automated transfer of the complete HPLC fractions (comprehensive on-line HPLC-GC, i.e. HPLCxGC). Flame ionization detection (FID) was used for the estimation of concentrations, mass spectrometry (MS) for identification work. This method was applied to investigate whether pulsed light (PL) treatment for the microbiological decontamination of polypropylene packaging materials produces reaction products requiring an evaluation to meet regulatory requirements. To demonstrate the safety of PL treatments with regard to the formation of reaction products, i.e. that no component is formed that could endanger human health, basically comprehensive analysis of components potentially migrating into food is required, but comprehensiveness cannot be proven and remains an approximation. The threshold concentration in the film was estimated either from the conventional European non-detection limit of 0.01 mg/kg food or the concept of the threshold of toxicological concern (TTC) for an unknown substance, i.e. an exposure to 0.15 mu g per person and day. PL treatment of the films containing Irgafos 168 produced several new components exceeding these limits, i.e. a toxicological safety assessment would probably be required. No such peaks were detected for Tinuvin 326, Irganox 1076 and Chimassorb 81. No degradation of the polymer was detected