Truth in Fiction – Killer Kidney Beans

I can be an avid reader. Unless it’s something for the veg/animal rights book club that I belong to, I’m typically reading fiction. I picked up Dead Heat by Dick Francis. He’s one of my favorite authors because he writes interesting and suspenseful action novels, usually with a horse theme.

I’ve read many Dick Francis novels over the last decade. If I had to put a number to it, probably over 25. Yet, this one was a first in two ways – it mentioned vegans, and I actually learned a real fact about a food that I eat regularly.

The story involves a chef who caters two meals at a horse racing track. There is a nod to preparing food for vegetarians and “one vegan who had preordered grilled musthrooms to start, roasted vegetables for main course and a fresh fruit salad for dessert”.

Yeah, I can relate to being the vegan who has to preorder special meals. He got that part right. But then in an interesting twist, someone later dies, and the suspect is food poisoning from kidney beans. Francis says “Every chef, every cook, every housewife, even every schoolboy, knows that kidney beans have to be boiled to make them safe to eat.” (chapter 6)

Hmmm .. well, that is everyone except me! I finished the book last night, and this morning did a quick google search on “kidney beans toxic”. And it’s true, a few undercooked kidney beans can make you sick in just a few hours.

And I quote from the FDA

Phytohaemagglutinin, the presumed toxic agent, is found in many species of beans, but it is in highest concentration in red kidney beans (Phaseolus vulgaris). The unit of toxin measure is the hemagglutinating unit (hau). Raw kidney beans contain from 20,000 to 70,000 hau, while fully cooked beans contain from 200 to 400 hau. White kidney beans, another variety of Phaseolus vulgaris, contain about one-third the amount of toxin as the red variety; broad beans (Vicia faba) contain 5 to 10% the amount that red kidney beans contain.

The syndrome is usually caused by the ingestion of raw, soaked kidney beans, either alone or in salads or casseroles. As few as four or five raw beans can trigger symptoms. Several outbreaks have been associated with “slow cookers” or crock pots, or in casseroles which had not reached a high enough internal temperature to destroy the glycoprotein lectin. It has been shown that heating to 80°C may potentiate the toxicity five-fold, so that these beans are more toxic than if eaten raw. In studies of casseroles cooked in slow cookers, internal temperatures often did not exceed 75°C.

The onset time from consumption of raw or undercooked kidney beans to symptoms varies from between 1 to 3 hours. Onset is usually marked by extreme nausea, followed by vomiting, which may be very severe. Diarrhea develops somewhat later (from one to a few hours), and some persons report abdominal pain. Some persons have been hospitalized, but recovery is usually rapid (3 – 4 h after onset of symptoms) and spontaneous.

I’ll still eat and enjoy cooked kidney beans. But it gives me a new appreciation and respect for these powerful little beans.