Otmar Zoller

Furan in food: Headspace method and product survey

Headspace gas chromatography-mass spectrometry (GC-MS) has been adapted for the efficient determination of furan in foods. Levels of furan in various foods were measured in order to identify the products that contribute most to the human intake of furan. Highest amounts were found in products that were heat treated in sealed containers such as jarred and canned food products and in crusty and dry products such as snacks, biscuits, bread crust, roasted wheat flour and roasted coffee beans. Of the analysed jarred baby food products those containing only meat and starch from rice and corn had low levels of furan. In addition, the fruit products showed similar low levels. Clearly higher concentrations were found in the vegetable and vegetable–meat products. For the adult population coffee seems to be an important product with respect to furan intake. Coffee brews from espresso-type machines had considerably higher amounts of furan than other coffee brews. This type of coffee is considered by experts to have the best coffee aroma. It is assumed that for regular coffee consumers coffee is the most important source of furan intake.

Occurrence of heterocyclic aromatic amines in the Swiss diet: analytical method, exposure estimation and risk assessment

A total of 86 meat samples, prepared in restaurants or homes, ready to eat (including poultry and fish) and 16 commercial samples such as bouillon (cubes) were analysed for heterocyclic aromatic amines (HAA). The analytical method consisted of an acidic extraction, clean-up on a cation exchange cartridge followed by an analogous HPLC step to recover the following HAA: IQ, MeIQ, MeIQx, 4,8-DiMeIQx, PhIP and 7,8-DiMeIQx. The HAA containing HPLC-fractions were collected, the HAA identified and quantified using two RP-HPLC-systems of different retention properties (UV-detection). The limit of quantitation was in the range of 0.2–0.4ng/g and the relative repeatability 6–15%. The recovery of PhIP was lower than for the other HAA analysed (less than 80%) and a correction factor was applied. No significant differences of the HAA-concentration were found in samples from homes and restaurants. half of the total samples contained HAA at the following frequencies: PhIP and MeIQx 33% (each), 4,8-DiMeIQx 11% and MeIQ 4%; 7,8- DiMeIQx and IQ were not detected. The frequencies in commercial products were for MeIQx 31%, 7,8- DiMeIQx 19%, IQ 13% and PhIP 6%; MeIQ and 4,8-DiMeIQx were not found. Based on these data, the average exposure of Swiss adults to HAA was estimated to be 5ng/kg body mass per day, commercial products contributing less than 10%. The theoretical excess cancer risk due to this intake was estimated on the base of the carcinogenic potency of the HAA in long-term animal experiments by linear extrapolation. The resulting risk in the order of 10-4 at the maximum is discussed in terms of Swiss epidemiological data.

High-performance liquid chromatographic determination of Δ9-tetrahydrocannabinol and the corresponding acid in hemp containing foods with special regard to the fluorescence properties of Δ9-tetrahydrocannabinol.

A solvent programmed reversed-phase HPLC method with UV detection for the determination of delta9-tetrahydrocannabinol (THC) and delta9-tetrahydrocannabinolic acid A (THCA-A) in foods containing parts of hemp such as edible oil, herb-teas (infusion), herbal hemp or hempseed is presented. The THC peak is also detected by fluorescence. The detection limits with UV detection are 0.01 ng for THC and 0.05 ng for THCA-A and with fluorescence detection 0.1 ng for THC. The relative standard deviation under repeatability conditions of the chromatographic procedure is about 0.5% and that of the over-all analytical procedure for THC in vegetable oils 2% (concentration range of 10-100 mg/kg).

Endocrine activity of alternatives to BPA found in thermal paper in Switzerland.

Alternatives to bisphenol A (BPA) are more and more used in thermal paper receipts. To get an overview of the situation in Switzerland, 124 thermal paper receipts were collected and analyzed. Whereas BPA was detected in most samples (n=100), some alternatives, namely bisphenol S (BPS), Pergafast® 201 and D-8 have been found in 4, 11 and 9 samples respectively. As no or few data on their endocrine activity are available, these chemicals and bisphenol F (BPF) were tested in vitro using the H295R steroidogenesis assay. 17β-Estradiol production was induced by BPA and BPF, whereas free testosterone production was inhibited by BPA and BPS. Both non-bisphenol substances did not show significant effects. The binding affinity to 16 proteins and the toxicological potential (TP) were further calculated in silico using VirtualToxLab™. TP values lay between 0.269 and 0.476 and the main target was the estrogen receptor β (84.4 nM to 1.33 μM). A substitution of BPA by BPF and BPS should be thus considered with caution, since they exhibit almost a similar endocrine activity as BPA. D-8 and Pergafast® 201 could be alternatives to replace BPA, however further analyses are needed to better characterize their effects on the hormonal system.

Natural occurrence of bisphenol F in mustard

ABSTRACT Bisphenol F (BPF) was found in mustard up to a concentration of around 8 mg kg−1. Contamination of the raw products or caused by the packaging could be ruled out. Also, the fact that only the 4,4ʹ-isomer of BPF was detected spoke against contamination from epoxy resin or other sources where technical BPF is used. Only mild mustard made of the seeds of Sinapis alba contained BPF. In all probability BPF is a reaction product from the breakdown of the glucosinolate glucosinalbin with 4-hydroxybenzyl alcohol as an important intermediate. Hot mustard made only from brown mustard seeds (Brassica juncea) or black mustard seeds (Brassica nigra) contained no BPF. BPF is structurally very similar to bisphenol A and has a similar weak estrogenic activity. The consumption of a portion of 20 g of mustard can lead to an intake of 100–200 µg of BPF. According to a preliminary risk assessment, the risk of BPF in mustard for the health of consumers is considered to be low, but available toxicological data are insufficient for a conclusive evaluation. It is a new and surprising finding that BPF is a natural food ingredient and that this is the main uptake route. This insight sheds new light on the risk linked to the family of bisphenols. Graphical Abstract

Chemical fingerprinting identifies Echium vulgare, Eupatorium cannabinum and Senecio spp. as plant species mainly responsible for pyrrolizidine alkaloids in bee-collected pollen

ABSTRACT Various studies have shown that bee-collected pollen sold as nutritional supplements may contain toxic pyrrolizidine alkaloids (PAs) and, thus, pose a potential health risk for consumers. The level of contamination may vary according to its geographical and botanical origin. Here, the PA content of pollen produced in Switzerland was studied and 32 commercially available bee-collected pollen supplements produced between 2010 and 2014 were analysed. In addition, at what time period bees collect PA-containing pollen was investigated. Hence, this study looked into the occurrence of PAs in pollen samples collected daily during two-to-three consecutive seasons. Furthermore, the PA spectrum in pollen was compared to the spectrum found in flower heads of PA-plants to unambiguously identify plants responsible for PA contamination of pollen. The PA concentration of commercial and daily collected pollen was determined by target analysis using an HPLC-MS/MS system, allowing the detection of 18 different PAs and PA N-oxides found in the genera Echium, Eupatorium and Senecio, while the comparison of the PA spectrum in pollen and flower heads was performed by LC-HR-MS, allowing the detection of all PA types in a sample, including saturated, non-carcinogenic PAs. Of the commercially available pollen, 31% contained PAs with a mean concentration of 319 ng/g, mainly Echium- and Eupatorium-type PAs, while the PA concentrations were below the limit of quantitation (LOQ) in 69% of the pollen samples. Bees collected pollen containing Echium-type PAs mainly in June and July, while they gathered pollen containing Eupatorium-type PAs from mid-July to August. Senecio-type PAs appeared from June to September. Comparison of the PA array in pollen and plants identified E. vulgare and E. cannabinum as the main plants responsible for PA contamination of Swiss bee-collected pollen, and to a lesser extent also identified plants belonging to the genus Senecio.

Glyphosate residues in Swiss market foods: monitoring and risk evaluation

ABSTRACT A total of 243 samples of diverse foodstuffs were analysed for glyphosate and aminomethylphosphonic acid (AMPA) using a liquid chromatography triple quadrupole mass spectrometry (LC/MS/MS) method with a relatively low limit of quantification in the range of 0.0005–0.0025 mg kg−1. Main contributors for dietary glyphosate and AMPA intake were cereals and pulses. The results suggest that pasta is a very important foodstuff for dietary glyphosate residue intake in Switzerland. Interestingly all samples of wine, fruit juice and nearly all samples of honey tested positive for glyphosate although at very low levels. A dietary risk assessment was conducted. Food products for analysis were not selected purely at random, rather products were selected for which high levels of glyphosate residues were suspected. However, even in samples where high residue levels were expected, no exceedances of maximum residue levels were found. Consequently, human exposure did not exceed neither acceptable daily intake nor acute reference dose. Therefore, glyphosate residues found in the sampled foodstuffs from the Swiss market were of no concern for human health.