But in all cases - fugu, rhubarb and venomous snakes - the poison is removed before consumption. Just as there can be mistakes when preparing fugu, there can also be mistakes when preparing rhubarb and snakes.
So, why treat one - the Japanese fugu - differently from other poisonous eats?
An excellent question. I will answer you in list form:
1. The venom in snakes is confined to the head -- the venom glands, ducts and fangs with spillage into the oral cavity in some species.
2. The venom, fangs/teeth, mouth, ducts and venom glands are easily removed by simply chopping off the snakes head. The flesh or other organs of the snake do not contain venom or any poisonous substance.
3. BUT even if one were to eat/drink snake venom, it is not dangerous by swallowing because:
a. it must be injected into/under the skin and/or a blood vessel to be harmful
b. it is rendered harmless by the acid in the stomach anyway
c. is only possibly dangerous if swallowed if one has an ulcer
4. Rhubarb contains high levels of oxalates or salts of oxalic acid which if ingested, are
absorbed into the blood stream, can damage the kidneys. Spinach leaves which are eaten
also contains this substance but in much lower amounts.
5. The large fleshy stem of rhubarb is not toxic and is used as pie filling.
6. The toxic parts of rhubarb, the leaves, are easily removed. Since the poison is embedded in the leaves there is no chance of contaminating or spilling any onto the stem which is eaten. This is not the case in fugu:
A. Fugu contains one of the deadliest substances on the earth, tetrodotoxin, a neurotoxin
that rapidly results in respiratory and cardiac arrest. Just 1/1000th of a gram is
considered lethal in an average adult human.
B. The lethal toxin in fugu is sequestered in the liver, one of the largest organs in the
body after the skin; when a chef cuts this out it is not difficult to miss a practically
microscopic trace of the toxin infected tissue which would be left behind in the fish to
be served. Such a trace can be fatal.
This is why in Japan chefs must be licensed to prepare this fish but that fact does not preclude others from doing so, particularly outside Japan and throughout South Asia. It also does not preclude a licensed chef from accidentally leaving a trace behind.
Serving the liver pate of fugu or, for that matter, fugu preparation by a chef who is not licensed is illegal in Japan. The scientific advances made by the mariculturists in raising
toxin free fugu means that the liver pate can now be served with impunity and, in addition, that licensed chefs are not necessarily needed to prepare fugu in public restaurants.
It also brings down the cost of the dish considerably as without prep this is a cheap or trash fish.
Comparing fugu with venomous snakes and rhubarb is comparing apples and oranges. And besides this thread is about fugu, not snakes or rhubarb. The toxin in fugu is much deadlier, drop for drop, than rattlesnake venom or rhubarb leaves. And it is much easier to leave traces behind. And in the case of snake venom it isn't even dangerous when swallowed, only when injected or somehow allowed to reach the blood stream. This is why snakes administrer their venom with hollow fangs connected by ducts to venom glands. They work very much like a hypodermic needle. A dead headless snake will not hurt anyone who fries it up and eats it
even if there remains traces of the snakes venom on the food.
You just can't compare fugu against rattlesnakes or rhubarb.