Hey, Matt: Why does all seafood smell the same, even though it comes from such different kinds of animals (mollusks, arthropods, vertebrates)? Okay, so maybe it doesn’t all smell exactly the same, but similar. The only thing all those creatures have in common is that they live in seawater and that “seafood smell” does not smell like seawater. — Ernie Bornheimer, Lemon Grove

“Ask him where he buys his fish,” Matthew.

No, Grandma. What’s the dif?

“Because I don’t want to make a mistake and shop there, that’s why. If I understand what he means, ‘seafood smell’ is no good. Once fish smells like fish, it’s only good for plant food.”

Well, you’re the brains of the culinary outfit here, so I guess I gotta take your word for it. So, what’s wrong with fish smelling like fish?

“Fish, shrimp, clams, whatever, straight out of the sea smell like their environment — seawater. Salty high tide. Once they’ve been out for a while, we’re talking low tide.

“Whatever kind of seafood — whatever combination of feet, claws, shells, fins — they’re all made of the same type of protein (different from mammal protein), which is why a very fresh clam doesn’t smell so different from a very fresh flounder. And when they’re very fresh, you’ve gotta get your nose right down into them to smell anything at all because they’re pretty much sterile. Smells are caused by vapors, and fresh fish don’t have much in the way of vapors.

“Fish don’t start smelling like fish until we start handling them and transfer some bacteria or molds onto the flesh and until the muscle meat starts breaking down. Now you’ve got vapors. At first it’s not so bad. A salty air smell with a little bit of fish — just enough so you know you’re not in the detergent aisle or something. Seafood flesh decomposes faster than, say, beef because of the type of protein it is. And think about this: seafood spends most of its time in cold water, which means any bacteria in its system has to be pretty tough and efficient. Once they’re out of the water and getting toasty, it’s a microbe festival. And microbes in decomposing flesh give off lots of vapors.

“Oh, Matthew, that baked Alaska was for dinner!”

There’s plenty left. Chill, Grandma. Don’t get your microbes in a twist. Ha-ha-ha. Uh, you’re not laughing. C’mon, Grandma, lighten up.

“Do you care about this, Matthew? Should I even bother to continue?”

Heck, no, I don’t care. But Ernie does, so I guess that means I’ve gotta listen. So go ahead. Warmed-up fish?

“Fish smell is made of a combination of ammonia and sulfur, and trimethylamine, which comes from the decomposing protein. Lemons or vinegar help cover the trimethylamine smell, which is why we’ve traditionally served fish with lemon.

“Fish that eat other fish have good fish-digesting microbes in their guts. When we fish those fish out of the drink, well, the microbes can’t tell the difference between dinner and a dead host, so decomp again is pretty quick and efficient. In other words, seafood was made to smell, I’m afraid. That also explains why, when you’re fishing, you should gut your catch ASAP, to keep digestive bacteria away from the flesh.

“Oh, Matthew, what are you doing now? Are you still trying to figure out how to use that cell-phone camera? Are you listening at all?”

Yeah, yeah, sure. But I’ll tell you, I’ve only got maybe two more minutes left on my meter and after that I’m dust. Does Ernie really need all this information?

“Maybe not. But I’m sure Ernie would love to hear the story about how you went to answer your phone the other day and ended up taking a picture of your ear.

“Smell is so important in gauging the freshness of fish that the feds actually employ squads of fish sniffers to smell imported seafood before it hits the market. These sniffers rate what they smell on a scale of 0 to 100. One hundred is pretty much poison. Hey, Matthew, how about applying for one of those jobs? It’s skilled, white-collar work. A lab coat has a white collar, right? And it’s got to be better than this annoying job you have now.”

Oh, yeah, I’ll get right on it. Manipulate my résumé to make it look like I’ve got experience. Well, the Reader office is pretty ripe, does that count?

“They’re smelling for the bad components they officially call ‘fishiness, oxidation, mustiness, yeastiness, sweetness, sourness, cheesiness, rancidness, cardboard, sulfur, and ammonia.’ That’s quite a trained nose to sort out all those smells.”

They should hire basset hounds.

“Don’t get smart, Matthew.”

No worry there, Grandma.

“Well, anyway, they’re starting to develop machines to do the sniffing and sorting. I wonder what kind of job a laid-off fish sniffer would qualify for?”