Acrylamide in a fried potato dish (rösti) from restaurants in Zurich, Switzerland

Rösti, a fried potato product, is a large contributor to acrylamide exposure locally in Switzerland. A survey of 55 dishes prepared by 51 restaurants in the city of Zurich showed that the average rösti contained 702 µg/kg acrylamide. By analysing the content of reducing sugars in the potatoes used for frying, it is shown that with simple measures, the exposure to acrylamide could easily be reduced by factor 2 or more, while even improving the culinary experience. Though rösti is a typical dish in the German-speaking areas in Switzerland, the result may be of general interest for fried potato products which are popular in large areas of Central Europe.

Mineral oil in human tissues, part II: characterization of the accumulated hydrocarbons by comprehensive two-dimensional gas chromatography

Mineral oil hydrocarbons are by far the largest contaminant in the human body. Their composition differs from that in the mineral oils humans are exposed to, and varies also between different tissues of the same individual. Using the presently best technique for characterizing the composition of mineral oil hydrocarbons, comprehensive two-dimensional gas chromatography (GC×GC), the hydrocarbons in human tissues were compared to those of various mineral oils. This provided information about the strongly accumulated species and might give hints on the flow path through the human body. The selectivity of accumulation is probably also of interest for the risk assessment of synthetic hydrocarbons (polyolefins). GC×GC grouped the MOSH into classes of n-alkanes, paraffins with a low degree of branching, multibranched paraffins and naphthenes (alkylated cyclic hydrocarbons) with 1-4 rings. Metabolic elimination was observed for constituents of all these classes, but was selective within each class. The MOSH in the subcutaneous abdominal fat tissues and the mesenteric lymph nodes (MLN) had almost the same composition and included the distinct signals observed in mineral oil, though in reduced amounts relative to the cloud of unresolved hydrocarbons. The MOSH in the liver and the spleen were different from those in the MLN and fat tissue, but again with largely identical composition for a given individual. Virtually all constituents forming distinct signals were eliminated, leaving an unresolved residue of highly isomerized hydrocarbons.

Comprehensive two-dimensional gas chromatography for characterizing mineral oils in foods and distinguishing them from synthetic hydrocarbons

Many foods are contaminated by hydrocarbons of mineral oil or synthetic origin. High performance liquid chromatography on-line coupled with gas chromatography and flame ionization detection (HPLC-GC-FID) is a powerful tool for the quantitative determination, but it would often be desirable to obtain more information about the type of hydrocarbons in order to identify the source of the contamination and specify pertinent legislation. Comprehensive two-dimensional gas chromatography (GC×GC) is shown to produce plots distinguishing mineral oil saturated hydrocarbons (MOSH) from polymer oligomeric saturated hydrocarbons (POSH) and characterizing the degree of raffination of a mineral oil. The first dimension separation occurred on a phenyl methyl polysiloxane, the second on a dimethyl polysiloxane. Mass spectrometry (MS) was used for identification, FID for quantitative determination. This shows the substantial advances in chromatography to characterize complex hydrocarbon mixtures even as contaminants in food.

Evidence for two karyotypic variants of the lesser horseshoe bat ( Rhinolophus hipposideros , Chiroptera, Mammalia) in Central Europe

Three different diploid chromosome numbers (2n = 54, 56 and 58) have been reported in the lesser horseshoe bat, Rhinolophus hipposideros. Asia Minor and the Middle East are inhabited by R. hipposideros specimens with 58 chromosomes. In Europe, specimens with 56 chromosomes have been recorded from several localities in the Czech Republic, Slovakia, Italy and Greece. Up to now, specimens with 54 chromosomes have been reported only from Spain and possibly from Switzerland. With the record of 54 chromosomes in specimens from Germany presented here, the distributional area of this variant is expanded into Central Europe. According to the cytogenetic data presently available, we presume that the European R. hipposideros population is divided into a western form (from Spain to Germany) with a 2n = 54 karyotype and an eastern form (from the Czech Republic to Greece) with a 2n = 56 karyotype. This study presents banded karyotypes for the 2n = 54 and 2n = 56 variants for the first time. In addition, chromosomal arm homology to the vespertilionid bat species Myotis myotis revealed by chromosome painting is reported. Whether the variants could represent separate species is also discussed.

Aromatic hydrocarbons of mineral oil origin in foods: method for determining the total concentration and first results

An online normal phase high-performance liquid chromatography (HPLC)-gas chromatography (GC)-flame ionization detection (FID) method was developed for the determination of the total concentration of the aromatic hydrocarbons of mineral oil origin with up to at least five rings in edible oils and other foods. For some samples, the olefins in the food matrix were epoxidized to increase their polarity and remove them from the fraction of the aromatic hydrocarbons. This reaction was carefully optimized, because also some aromatics tend to react. To reach a detection limit of around 1 mg kg(-1) in edible oils, an off-line enrichment was introduced. Some foods contained elevated concentrations of white paraffin oils (free of aromatics), but the majority of the mineral oils detected in foods were of technical grade with 20-30% aromatic hydrocarbons. Many foods contained mineral aromatic hydrocarbons in excess of 1 mg kg(-1).

Contamination of grape seed oil with mineral oil paraffins

The contamination of 11 commercial grape seed oils with paraffins of mineral oil origin was analyzed by online-coupled HPLC-HPLC-GC-FID and ranged from 43 to 247 mg kg(-1). The analysis of the marc and seeds indicated that the contamination is primarily from the peels. Since superficial extraction of the seeds with hexane removed most of the mineral paraffins, the contamination of the seeds is largely on the surface, perhaps transferred from the peels during storage of the marc. Mechanical purification of the seeds combined with washing with hexane reduced the contamination of the oil by a factor of about 10. The refining process removed 30% of the mineral paraffins, primarily the more volatile components. Oil obtained from the seeds of fresh grapes, including grapes not having undergone any phytochemical treatment, contained clearly less mineral paraffins (up to 14 mg kg(-1)), and the peels were less contaminated, suggesting an environmental background contamination. To this an additional contamination might be added by a treatment of the grapes used for wine making.