Pyrrolizidine alkaloids and tropane alkaloids in milk samples from individual dairy farms of the German federal states of Bavaria and Schleswig-Holstein

1,2-Dehydro-pyrrolizidine alkaloids (PA), their corresponding <i>N</i>-oxides (PANO) and tropane alkaloids (TA), are toxic plant metabolites. If plant material, containing these toxins, is present in the feed of dairy cows these toxins can be transferred into milk. Here, milk was sampled directly from dairy farms in the German federal states of Bavaria and Schleswig-Holstein in 2020–2022 in order to investigate a possible contamination of milk at the production stage. In total, 228 milk samples were analysed for 54 PA/PANO and two TA by a sensitive LC–ESI-MS/MS method. In addition, a subset of milk samples (<i>n</i> = 85) was independently analysed for TA by a cooperating laboratory for verification. PA/PANO were found in 26 samples (11%) with a low median sum content of the contaminated samples of 0.024 µg/L. The highest level of contamination was 5.6 µg/L. Senecionine-, lycopsamine- and heliotrine-type PA/PANO were detected. In four samples (1.8%), atropine was determined up to 0.066 µg/L. The toxin levels in the milk samples hardly contributed to the total daily exposure. These data are first-time results on contamination rates and levels occurring in milk from individual dairy farms, based on a large sample number.

1,2-脱氢吡咯里西啶生物碱（1,2-Dehydro-pyrrolizidine alkaloids，PA）、其对应的N-氧化物（PANO）以及莨菪烷生物碱（tropane alkaloids，TA）均为有毒植物代谢产物。若奶牛饲料中混入含有此类毒素的植物原料，毒素可迁移至牛乳中。本研究于2020—2022年间，直接从德国巴伐利亚州与石勒苏益格-荷尔斯泰因州的奶牛场采集牛乳样品，旨在调查牛乳在生产环节的潜在污染情况。总计228份牛乳样品采用灵敏的液相色谱-电喷雾电离串联质谱法（LC–ESI-MS/MS），针对54种PA/PANO与2种TA开展检测。此外，85份子样品由合作实验室独立开展TA检测以进行结果验证。26份样品（占总样品量的11%）检出PA/PANO，污染样品的总含量中位数仅为0.024 μg/L，处于较低水平，最高污染浓度达5.6 μg/L。检出类型涵盖千里光宁（Senecionine）型、倒千里光碱（lycopsamine）型与天芥菜碱（heliotrine）型PA/PANO。另有4份样品（占比1.8%）检出阿托品（atropine），最高浓度达0.066 μg/L。牛乳样品中的毒素水平几乎未对人体每日总暴露量产生显著贡献。本研究所得数据为基于大样本量的个体奶牛场牛乳污染率与污染水平的首次报道结果。