Investigation of aflatoxin and ochratoxin A contamination of seized cannabis and cannabis resin samples.

Recreational cannabis is being legalized in more and more countries, and methods for the determination of contaminants, thereunder mycotoxins, start to emerge in scientific literature. On the other hand, cannabis continues being available on the illegal market without any quality control at all. Today, no information about mycotoxin contamination of illegal cannabis is available in literature. Therefore, in order to increase knowledge about mycotoxin contamination of cannabis, aflatoxins (AF) and ochratoxin A (OTA) were analyzed in 142 samples of illegal cannabis seized on the local market using a method based on HPLC-FLD detection, after clean up with immuno-affinity cartridges. AF were derivatized prior to detection with a Kobra cell. No AF contamination (LOD = 0.04 µg/kg) was detected in any of the samples analyzed. OTA however was detected in about one-third of the samples with an average concentration of 4.30 µg/kg (range from 1.02 to 16.21 µg/kg). No significant difference was observed between resin and herbal samples. Overall, the concentrations remain low and do not suggest an issue to human health if the cannabis consumption remains moderate.

Epimerization of ergot alkaloids in feed.

Chronic intake of cereals contaminated with ergot alkaloids can cause ergotism and result in the loss of toes and fingers or even death. Today, due to common risk management practices, ergotism is rare as a human disease but remains a problem in livestock husbandry. Each alkaloid coexists under two forms (R and S), though only the R-form presents toxic effects. The epimerization occurs spontaneously but the mechanisms remain globally unknown. Therefore, different processing methods were evaluated for their respective influences on the epimerization. The results suggest that ergotamine and ergosine are very stable ergot alkaloids, and neither their concentrations, nor their respective R/S ratios, are significantly influenced by heating, protic solvents or UV light. In contrast, for ergocristine, ergokryptine, ergocornine and ergometrine, heating can decrease the concentrations of these alkaloids and heat, protic solvents and UV light influence the R/S ratio towards the S-form, though the respective influence on the epimerization of these compounds is variable. In addition, the total concentration of all ergot alkaloids is reduced through heating. However, all these effects are not strong enough to change the composition of ergot alkaloids in feed substantially and to transform toxic feed into non-toxic feed.

Development of a UHPLC-FLD method for the analysis of ergot alkaloids and application to different types of cereals from Luxembourg.

Ergot alkaloids are toxins produced by some species of fungi in the genus Claviceps, that may infect rye and triticale and, in a minor degree, other types of cereals. In this study, a new UHPLC-FLD method for the quantification of the six major ergot alkaloids as well as their corresponding epimers was developed. The sample preparation was done by a solid-liquid extraction with acetonitrile and clean-up via freeze-out. The method was fully validated and then applied to 39 samples (wheat, rye, triticale, and barley) harvested in Luxembourg in 2016. Samples were sieved (1.9 × 20 mm) prior to analysis in order to remove sclerotia, hosting the alkaloids. However, 23 samples still contained at least one ergot alkaloid > LOQ and concentrations of the sum of the 6 ergot alkaloids ranged from 0.3 to 2530.1 µg/kg. Interestingly, the highest concentrations were measured in wheat and not in rye or triticale, suggesting that all kinds of cereals should be included in monitoring programs. The outcome of this study allowed giving a first overview of ergot alkaloid concentrations in cereals harvested in Luxembourg, and the measured concentrations were in similar ranges than in other parts of the world (e.g., Canada, France, Germany).

Investigation of a staphylococcal food poisoning outbreak combining case-control, traditional typing and whole genome sequencing methods, Luxembourg, June 2014.

In June 2014, a staphylococcal food poisoning outbreak occurred at an international equine sports event in Luxembourg requiring the hospitalisation of 31 persons. We conducted a microbiological investigation of patients and buffet items, a case-control study and a carriage study of catering staff. Isolates of Staphylococcus aureus from patients, food and catering staff were characterised and compared using traditional typing methods and whole genome sequencing. Genotypically identical strains (sequence type ST8, spa-type t024, MLVA-type 4698, enterotoxin A FRI100) were isolated in 10 patients, shiitake mushrooms, cured ham, and in three members of staff. The case-control study strongly suggested pasta salad with pesto as the vehicle of infection (p<0.001), but this food item could not be tested, because there were no leftovers. Additional enterotoxigenic strains genetically unrelated to the outbreak strain were found in four members of staff. Non-enterotoxigenic strains with livestock-associated sequence type ST398 were isolated from three food items and two members of staff. The main cause of the outbreak is likely to have been not maintaining the cold chain after food preparation. Whole genome sequencing resulted in phylogenetic clustering which concurred with traditional typing while simultaneously characterising virulence and resistance traits.

Determination of polycyclic aromatic hydrocarbons in smoked and non-smoked black teas and tea infusions.

This study describes the occurrence of polycyclic aromatic hydrocarbons (PAHs) in smoked tea and tea infusions, via the monitoring of benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo(a)pyrene (PAH4) that have been chosen as indicators for the occurrence of PAHs in food by the European Food Safety Agency. The concentrations ranged from 1.2 µg/kg for benzo(b)fluoranthene to 125.0 µg/kg for benzo(a)anthracene in smoked tea leaves, and from 0.6 µg/L for benzo(a)anthracene to 1.2 µg/L for benzo(b)fluoranthene in smoked tea infusions. Benzo(a)pyrene was never detected in infusions. The concentrations in non-smoked tea leaves ranged from 0.6 µg/kg for benzo(a)anthracene to 10.8 µg/kg for benzo(b)fluoranthene. It was shown that the concentrations of benzo(a)anthracene and chrysene were higher in smoked tea than in non-smoked tea while no difference was observed for benzo(b)fluoranthene and benzo(a)pyrene. The concentrations of PAHs in tea infusions are low compared to other foodstuffs, but the migration rates from leaves into water are high (82-123%).

Low-level detections of Sudan I, II, III and IV in spices and Chili-containing foodstuffs using UPLC-ESI-MS/MS.

Sudan dyes are red, synthetic azo dyes that are not allowed in foodstuffs in the European Union (Council Directive 94/36/EC). However, subppm levels of Sudan dye in spices are regularly reported, and it is assumed that these appearances are due to cross-contamination. In this paper, we present a newly developed fast and sensitive method for the quantification of Sudan I, II, III, and IV, using liquid-liquid extraction and UPLC-MS/MS analysis, and giving quantification limits ranging from 2.5 to 200 µg/kg. The method was applied to 21 samples, and 17 of them contained Sudan dye at low concentrations (3.3-8 709 µg/kg). Interestingly, it was observed that the distribution of Sudan dye in the sample is not homogeneous, which may lead to false negatives or to overestimations of the concentration, and that the pretreatment (blending or not) of the sample seriously influences the final result of the analysis.