DNA authentication of wild mushrooms in food products

Mushrooms have been consumed by humans for many thousands of years. While they can be gastronomically valued and nutritionally important, it has long been recognized that only select species of mushrooms are suitable for consumption. Adverse health effects of consuming poisonous mushrooms range from mild illness to death. Many valuable edible mushrooms are unable to be grown commercially, or it is impractical to do so, requiring them to be harvested from the wild. Products containing these wild-collected mushrooms are often sold with the nonspecific and undefined label "wild mushrooms," although in some cases particular species are listed in the ingredients. However, the ambiguity of the definition of "wild mushrooms" in foods makes it impossible to know which species are involved or whether they are truly wild-collected or cultivated varieties. As a consequence, any individual adverse reactions to consuming the mushrooms in these products cannot be traced to the source due to the minimal regula- tions around the harvest and sale of wild mushrooms. For this study, we set out to shed light on what species of fungi are being sold as "wild mushrooms" using DNA metabarcoding to identify fungal contents of various food products acquired from locally sourced grocers and a large online retail site. Twenty-six species of mushroom were identified across 12 food products, ranging from commonly cultivated species to wild species not represented in global DNA databases. One product labeled as "porcini" (a popular wild-collected group of edible mushrooms) was shown to contain potentially toxic species, including an Amanita sp. implicated in causing renal failure. Three of the food products sequenced were found to contain mushroom species that are widely considered as poisonous. This study demonstrates that a large variety of fungi can be sold as "wild mushrooms," even those that are commonly cultivated at industrial scales, and that ingredient labels do not always accurately describe the species included. Of more immediate concern, we demonstrate that poisonous mushrooms are being packaged and sold as food with a large distribution potential.

人类食用蘑菇的历史已长达数千年。蘑菇兼具烹饪价值与营养重要性，但长期以来学界已明确，仅有限的蘑菇物种适合食用。误食有毒蘑菇可引发从轻度不适直至死亡的严重健康危害。许多高价值食用蘑菇无法实现商业化栽培，或商业化种植不具可行性，因此只能通过野外采集获取。含有此类野生采集蘑菇的食品，通常会使用宽泛模糊的“野生蘑菇（wild mushrooms）”作为商品标签，仅部分产品会在配料表中标注具体物种。然而，食品中“野生蘑菇”的定义模糊不清，导致无法确认产品中涉及的具体物种，也无法判断其是真正野生采集还是人工栽培品种。因此，若消费者食用此类产品后出现不良反应，由于野生蘑菇的采集与销售监管近乎空白，无法追溯具体源头。本研究借助DNA宏条形码（DNA metabarcoding）技术，对从本地杂货店及大型在线零售平台采购的多款食品中的真菌成分进行鉴定，旨在明确被标注为“野生蘑菇”的食品究竟包含哪些真菌物种。研究团队在12款食品中共鉴定出26种蘑菇，涵盖常见栽培品种与未收录于全球DNA数据库的野生物种。其中一款标注为“牛肝菌（porcini）”的产品——一类广受欢迎的野生食用蘑菇类群——被检出含有潜在有毒物种，包括一种曾引发肾衰竭的鹅膏属（Amanita）真菌。另有3款经测序的食品被发现含有普遍认定为有毒的蘑菇物种。本研究证实，大量不同类别的真菌均可被标注为“野生蘑菇”售卖，其中甚至包括可实现工业化大规模栽培的品种，且配料标签往往无法准确反映所包含的物种。更值得警惕的是，本研究发现有毒蘑菇正被包装作为食品售卖，且具备广泛的流通潜力。