Identify this seafood from the Black Sea known in Romanian as “rapane”?

Question

Here on the Black Sea in Romania people are eating a shellfish called in Romanian "rapane" which they translate as "oyster" when I ask.

But they are elongated spiral shells which to me look nothing like the chunky flattish oyster shells in Australia. Besides which there is another Romanian word "stridie" for oyster and I can't find "rapane" in my print dictionary or any online dictionary. One person told me these are "sea oysters" as opposed to "ocean oysters". I've also been told they're not a native local species.

Here are some photos of a dead rapane shell on the beach. I'll replace them with better photos when I can take some:

Answer

They look like a species of whelk, which is a catch-all term for sea-snails. See the Wikipedia article here.

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What's the minimum time to cook raw prawns?

Question

I typically cook raw prawns in boiling water for around 3 minutes. If they go over a little bit longer they can tend to become rubbery.

Is there a minimum/optimum time a raw prawn should be boiled?

Answer

There is an optimal temperature to which they must be cooked, independent of method (boiling, frying, whatever). This temperature is 50 deg. C. (This is lower than safety guidelines; if you want to eliminate the foodborn illness risk, you must eat rubbery seafood). Once the inner temperature of seafood has risen above that, its proteins undergo an irreversible change called denaturation, which changes the texture.

The time needed for reaching this temperature varies a lot. It depends on the size of the prawns, their initial temperature, the temperature of your water, on the total mass of water in the pot and on the total mass of prawns in the pot.

If you find it impractical to impale a prawn on a digital thermometer every time you cook, you need to experiment. Keep the variables I mentioned constant, and boil prawns for different times. Find out how much they need before they go rubbery, and then stick to it, keeping all the other variables constant. In your case, this will probably correspond to the three minutes you mention. For somebody else, who boils a different amount of prawns per batch, it will be different.

There is no minimal time, just as there is no maximal time. The minimal temperature for them to taste cooked is 45 degrees C., but you can eat them at lower if you don't mind them tasting raw. You can find the minimum time for your case as described above. The legal minimum temperature for US food safety is 63 degrees. You can't legally approximate it by time, you must use a thermometer, or, at home, you can go much above it just to make sure - when seafood turns stiff and dry, you can be sure that it has reached 70 degrees.

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How to tell if frozen mussels are good?

Question

I live a far distance from any body of salt water, so the only mussels available are packaged frozen mussels.

I have always heard that cooked mussels must open or they are not good to eat, but when we cooked the frozen mussels only a few opened. I went ahead and ate them anyways, they tasted fine and did not make me sick.

Is it normal for frozen mussels to not open their shells when cooked? If it is normal, is there a way to tell if they are safe to eat?

Answer

'You shouldn't eat mussels that don't open' is an unfounded myth. It was first mentioned in a book by the British food writer Jane Grigson in the 1970s and grew through repetition to the point that 90% of cook books mentioned it in the 1990s.

The fact is, mussels that don't open after cooking are more likely to be safe than those that do.

You should, however, be careful to remove any mussels that have opened before cooking, as they'll be dead and likely to make you ill.

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How do you know when mussels are done?

Question

I bought 1/2 pound of mussels and cooked them in a cast iron skillet with a little white wine and some shrimp stock on boiling heat.

Almost all of them opened after about 15 minutes, some did not. The ones that opened were done perfectly, should I just throw away the rest, or would a few more minutes in the skillet be in order?

Answer

You should throw them out. Mussels that don't open were quite possibly dead and decomposing for an unknown period of time prior to cooking. You don't want to take a chance here.

Just in case future readers don't know, mussels, clams, and other in-shell shellfish are still alive when you buy them, and they should be still alive when you cook them.

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