Metabolic fate and toxicity reduction of aflatoxin B1 after uptake by edible Tenebrio molitor larvae.

The use of insects as food and feed is gaining more attention for ecological and ethical reasons. Despite the high tolerance of edible yellow mealworm (Tenebrio molitor) larvae to aflatoxin B1 (AFB1), the metabolic fate of the toxin along with its toxic potential in the insect is uncertain. The present study aimed at investigating the AFB1 mass balance and the metabolite formation in a feeding trial with AFB1-contaminated grain flour. T. molitor larvae tolerated the AFB1 level of 10,700 µg/kg in the feed, however, weight gain was decreased by 15% over a 4-weeks feeding period. The investigation of the phase I metabolite pattern revealed the formation of AFM1 and a novel presumably monohydroxylated compound in larvae extracts that was not formed by reference incubation with rat, bovine or porcine liver microsomes. Mass balance quantification of ingested AFB1 revealed that 87% of the initial toxin remain undetected in larval body or residue. Analysis of histone H2Ax phosphorylation in human liver cells as a surrogate for genotoxicity showed that extracts from exposed larvae did not exhibit an elevated toxic potential. Although toxicological uncertainties remain due to the undetected transformation products, the resulting mutagenicity of the edible larvae appears to be low.

Pyrrolizidine alkaloid profiling of four Boraginaceae species from Northern Germany and implications for the analytical scope proposed for monitoring of maximum levels.

Pyrrolizidine alkaloids (PAs) and their corresponding N-oxides (PANOs) have been determined in food and feed at levels relevant for consumer health. More than 660 different PAs have been detected, but few are available as reference substances for analytical demands. In the context of the European legislation on maximum levels of PAs in food products, a defined analytical scope of 21 PAs for determination has been suggested. An expansion of the scope from 21 to 35 PAs, including 14 structural isomers, is currently under discussion. In the present study, a target screening method was established for a comprehensive characterisation of PA profiles of the species Echium vulgare, Heliotropium europaeum, Cynoglossum officinale and Symphytum spp. to assess whether an expansion of the analytical scope is required to quantitatively cover the total PA contents of Boraginaceae species. The scope of the method comprised known and unknown PAs previously screened and confirmed in the respective plant extracts. A total of 176 PAs and PANOs were detected. The toxic 1,2-unsaturated PAs represent the predominant PA type with about 98% of the mean total content. This PA profiling demonstrates that an expansion of the scope from 21 to 35 PAs is required to adequately cover the mean total PA contents of Cynoglossum officinale and H. europaeum, whereas in the case of Symphytum spp. and Echium vulgare an expansion would not be necessary. ABBREVIATIONS: Pyrrolizidine alkaloid: PA, Pyrrolizidine alkaloid N-oxide: PANO, European Food Safety Authority: EFSA, German Federal Institute for Risk Assessment: BfR, ultra-high performance liquid chromatography: UHPLC, high-resolution: HR, tandem mass spectrometer: MS/MS, multiple reaction monitoring: MRM, data-independent MS2: ddms2, electrospray ionisation: ESI, limit of detection: LOD, limit of quantification: LOQ, gas chromatography coupled with mass spectrometry: GC-MS, fragmentation (data): MS2 (data), full scan: MS1, variable data-independent acquisition: vDIA, monoester esterified with a necic acid at position C9 of the necine base: O9-monoester, relative proportion: rel. prop., intraperitoneal: i.p., intravenous: i.v., higher-energy C-trap dissociation: HCD, all-ion fragmentation: AIF, parallel reaction monitoring: PRM.