一不小心会吃死人的日常食物
来源：BBC Learning English 作者：弗罗尼卡·格林伍德（Veronique Greenwood） 更新：2023年5月13日
我们都会偶尔放纵自己的味蕾。我们的记忆里或许都有吃了牡蛎或者生蚝以后闹肚子的惨痛经历。但是总体来说，我们现在吃得很健康。某些胆大的吃货冒着失去性命的危险去吃充满神经毒素的日本河豚，但我们大多数人只不过想吃得更健康更安全而已。然而，你所不知道的是，很多我们已经习以为常的食品实际上含有会引发疾病甚至死亡的毒素。
大黄馅饼和大黄果酱是受到人们喜爱的季节性美食。每个夏天，人们都用炖锅炖煮口感酸甜的红色大黄茎干，然后和面包一起食用。大黄有四处伸展的绿色叶片，曾经是在后院菜园中种植的观赏植物。它的茎干可食，但叶片却有剧毒。
一不小心会吃死人的日常食物1919年，蒙大拿州海伦娜（Helena, Montana）的一名医生向《美国医学会杂志》投稿，讲述了他遇到的一起病例：他出诊时看到一位脸色苍白、精疲力竭、呕吐不已的少妇。很明显这是一位孕妇，他发现"床单上摆着一具早产的6周大胎儿尸体"，但是胎盘却毫无血色，胎盘上的血液也没有凝固。少妇几小时后鼻孔流血而死亡。
大黄的茎干可以制作甜食，但叶片却不可食用（图片来源: iStock）
前一晚，她晚餐吃了大黄的茎和叶，她一个人吃了大部分的大黄叶片。她的丈夫只吃了一点，就感到身体虚弱、头晕目眩，但却没有生命危险。《美国医学会杂志》的编辑回信说，这位医生的直觉，女病人死于大黄叶片中毒，毒性物质可能是草酸，有可能是正确的。
"已经有了一些食用大黄叶片造成死亡的报告，"编辑在回信中写道。"一次大战期间，英国建议食用大黄叶片作为替代食品；当大黄叶片的中毒致死风险得到证实（出现了几个死亡病例）后，政府警告人们不要再食用大黄叶片。"大黄的茎和叶片中都含有草酸，但在叶片中的含量要高得多。草酸会导致肾衰竭，吃上一客数量的大黄叶片就会导致死亡，所以最好远离它。（大黄甚至出现在诺森伯兰郡安尼克花园中的有毒植物园里。这座有毒植物园培育了很多危险甚至致命的植物以招徕吸引胆大的游客。）
另一个例子是土豆，一般情况下，人们不会担心土豆的安全问题。但是如果把土豆暴晒在日光下，土豆表皮就会出现化学反应生成叶绿素，从而让表皮成为绿色，这是土豆准备发芽的标志。与此同时，土豆会生成一种称为龙葵素的物质。这种物质因一种剧毒植物龙葵而得名。土豆、番茄、茄子和龙葵都属于龙葵属植物。
一不小心会吃死人的日常食物
土豆发芽并变成绿色后，表明内含有毒物质龙葵素的含量出现上升（图片来源: iStock）
含有大量龙葵素的绿皮土豆将出现不同于普通土豆的性质，从而对食用者的健康产生危害。1978年秋季，伦敦南部有78名男学生在食用煮土豆后出现腹泻、呕吐和其他症状。后来的调查发现，他们食用的土豆早在当年夏天就一直储存在学校里，对土豆皮进行分析后发现其中的龙葵素含量极高。
所有学生最后都获得康复，"有些人在好几天里头脑不清、产生幻觉，"事故发生后第二年，《英国医学会期刊》发表的一篇简短文章记录说，这篇文章还强调了历史上食用绿色土豆导致的死亡病例。死亡人群基本都是无法获得医疗救治的、营养不良的人群。
龙葵素可作用于神经系统，破坏细胞内离子通道的正常运行。这或许能够解释某些中毒的学生为何会在恢复前出现抽搐症状。（土豆叶片和茎也含有龙葵素，因此不得食用）。
接骨木酒（Elderberry wine）是一种可口而浪漫的饮品。你如果自己制作接骨木酒，一定不要用这种植物的叶片当原料。包括叶片和未成熟果实在内，接骨木树几乎每个部分都含有氢氰酸或其前体物质。而当把果实煮熟后，其中的有害物质分子都被破坏，做成的接骨木果酱则十分安全。要是制作过程中没有煮熟，就会造成不良后果。
一不小心会吃死人的日常食物
接骨木必须煮熟才能去除其中的毒素（图片来源: iStock）
1983年，美国疾控中心发布的《发病率和死亡率周报》报道说，有8人被直升机运往位于加州蒙特利（Monterey, California）的一家医院。他们刚刚和另外17人一起从偏远地区由于"宗教/哲学"原因撤回。抵达后，有人拿出一瓶用附近采摘的野生接骨木制成的果汁。他们把接骨木果实压碎，和苹果汁、水和糖混合，但却没有加热。饮用接骨木果汁15分钟后，人们开始呕吐。摄入果汁最多的人当晚住进了医院。这些幸运的人最后都恢复了健康。
坐在餐桌旁，你应当感谢现代食品业者为我们提供了饮食安全警告，这些警告在很大程度上避免了食物中毒的发生。土豆、大黄馅饼和接骨木馅饼很好吃，如果正确储存和烹调，也不会对健康产生什么影响。
但是，要是想到这些日常食品内含致命毒素，你或许也会像勇于吃河豚的大胆吃货们一样感到心惊胆战。
The deadly danger in common foods
We've all suffered from the occasional overindulgence, and most of us likely have a few dodgy oysters or shrimp canapes ruefully enshrined in our memory. But by and large, we eat pretty safely these days. While some thrill-seekers search for fugu – the Japanese pufferfish, which is laden with the nerve poison tetradotoxin – and risk becoming one of its surprisingly numerous victims, most of us prefer a diet that is a good deal more innocuous. For all that, you might be surprised to learn that some familiar foods are next-door neighbours to things which can be very harmful to our health.
Rhubarb pies and jams are favourite seasonal delights. What's summer without a pan of tart red stems simmering on the stove, ready to be decanted into a waiting crust? The lush plants, with their spreading green leaves, are traditional adornments to the backyard vegetable garden. However, while the stems are edible, the leaves are extremely dangerous.
In 1919, a doctor in Helena, Montana, wrote to the Journal of the American Medical Association concerning the disturbing case of a young wife who was pale, exhausted, and vomiting when he arrived. She had apparently been pregnant – he found “the complete products of conception of about six weeks’ development, discharged into the bed clothes” – but the placenta was bloodless, and what blood there was would not coagulate. She died a few hours later, bleeding from the nose.
The night before, she'd made rhubarb stems and leaves for supper, and had eaten most of the leaves herself, while her husband had only a little. He was weak and dizzy, but did not die. The journal editors wrote back that the doctor's hunch – that she had been poisoned by the rhubarb leaves, probably by a substance called oxalic acid – was likely correct.
Solanine-rich green potatoes can produce some unpleasant effects in those who eat them
“A number of deaths from the use of the leaves have been reported,” they wrote. “During the war the use of the leaves as a food substitute was recommended in England; when the danger of fatal poisoning became apparent (owing to several deaths) warnings against the use of the leaves were issued.” Oxalic acid, as it happens, is present in both leaves and stems but in much higher quantities in the leaves. It causes kidney failure, and while you'd have to eat a hearty helping of the leaves to die, better just to avoid them altogether. (Rhubarb even appears in the Poison Garden at Alnwick Gardens in Northumberland, where a number of deadly and dangerous plants are cultivated in a macabre tourist attraction.)
Another peculiar case is that of the humble potato – which is not, in the usual course of things, anything to be concerned about. When it's stored in sunlight, however, chemical reactions at its surface turn it green with chlorophyll as it prepares to sprout. At the same time, a substance called solanine is also produced. It is named after the deadly nightshade (Solanum nigrum); potatoes happen to be a cousin to nightshade, as are tomatoes and eggplants.
Solanine-rich green potatoes, while not in the same class as this famous plant, can produce some unpleasant effects in those who eat them. In the autumn of 1978, 78 schoolboys in South London came down with diarrhea, vomiting, and other symptoms after eating boiled potatoes. Later investigation showed that the potatoes they'd eaten had been left in the school stores since summer, and an analysis of the peels revealed them to be packed with solanine.
All eventually recovered, “though some were confused and hallucinated for several days”, records a small British Medical Journal story on the incident from the following year, which noted that there had been reports of deaths from eating green potatoes in the past, though mainly in malnourished people who hadn't had medical help quick enough.
Solanine appears to interfere with the nervous system, impairing the normal functioning of ion channels in cells. This may explain why some of the poisoned boys showed strange twitches before they recovered. (Potato leaves and stems, incidentally, are to be avoided as entrees – solanine dwells there, too)
Almost every part of the elderberry tree contains hydrogen cyanide or its precursors, including the leaves and unripe berries
Elderberry wine, in turn, is a fine, romantic thing to drink. Just make sure, if you're making it yourself, that the romance doesn't extend to including any of the plant's leaves in your tincture. Almost every part of the elderberry tree contains hydrogen cyanide or its precursors, including the leaves and unripe berries. While cooking the berries destroys the offending molecules, rendering elderberry jams perfectly safe, consuming them without this precaution sometimes leads to unhappy results.
In 1983, the CDC's Morbidity and Mortality Weekly Report shows, eight people were helicoptered to a Monterey, California, hospital. They had gone on a remote “religious/philosophical” retreat with 17 others, and the day after they arrived, someone had brought out a juice made from wild elderberries gathered nearby. The berries had been crushed and mixed with apple juice, water, and sugar, but not apparently heated. Within 15 minutes of the juice's arrival, people began to vomit. The person who drank the most juice spent the night in the hospital. In the end, luckily, all recovered.
As you sit down at the table, you can be grateful to modern food safety precautions for eliminating most of the frightening guesswork in avoiding poisons. That bite of potatoes, or slab of rhubarb or elderberry pie, should be delicious, not deadly, if everything has been stored and cooked correctly.
But you may feel a frisson of excitement – perhaps something like what fugu eaters must feel – when you think of the dangers lurking nearby.