Mussels: What's that green stuff?

[Turtleboy]

Sometimes when I cook mussels, instead of having one "whole" mussel inside, they will seem to have two halfs, with some green stuff in the middle.

It looks pretty gross. What is that? Is that the same thing as the "tamale" in the lobster? Should I eat or chuck those?

[johnnyd]

Dude,

That stuff is totally toxic!!!!

No, really, If it bothers you don't look at it when you eat 'em, but that stuff is just fine. I have a couple pals who operate an aquaculture raft growing mussels on ropes - they couldn't tell me exactly what part of the animal that is, just that it's tasty.

Chow down!

[balmagowry]

Dude,

That stuff is totally toxic!!!!

No, really, If it bothers you don't look at it when you eat 'em, but that stuff is just fine.  I have a couple pals who operate an aquaculture raft growing mussels on ropes - they couldn't tell me exactly what part of the animal that is, just that it's tasty.

Chow down! 

I think of it as black rather than green - anyway, it's just the mussel's stomach. They all have it - it's just that in the ones that aren't split you don't see it because the flesh around it is relatively opaque (whereas a clam's flesh is relatively translucent, so the stomach shows through more).

[Pan]

Is it safer not to eat it, or is it really the filter that's at issue, since bivalves feed by filtering large quantities of water and thereby absorb and concentrate whatever impurities are in the water? (And no, I'm not being alarmist or telling people to stop eating bivalves, though I limit my consumption of bivalves other than scallops, whose filters as far as I know we don't eat.)

[balmagowry]

Is it safer not to eat it, or is it really the filter that's at issue, since bivalves feed by filtering large quantities of water and thereby absorb and concentrate whatever impurities are in the water? (And no, I'm not being alarmist or telling people to stop eating bivalves, though I limit my consumption of bivalves other than scallops, whose filters as far as I know we don't eat.)

No marine biologist I, so I can only answer empirically: I have been eating bivalves every summer for virtually my whole life - in fact during the leaner years of my childhood they were sometimes our steady and damn-near only diet - and never had any discernible health problem as a result. Of course, the bivalves in question were always perfectly fresh, and were caught in waters subject to very stringent shellfishing-safety testing, so the odds were pretty favorable to begin with. And I've never heard of anyone who, confronted with a bowl of beautiful steaming mussels, picked each one apart and performed a filterectomy on it before eating it!

EDIT to add: unlike us, many Europeans eat the whole scallop, filter and all - and I don't know of any scary statistics on that subject either.

Edited April 17, 2004 by balmagowry (log)

[Adam Balic]

Is it safer not to eat it, or is it really the filter that's at issue, since bivalves feed by filtering large quantities of water and thereby absorb and concentrate whatever impurities are in the water? (And no, I'm not being alarmist or telling people to stop eating bivalves, though I limit my consumption of bivalves other than scallops, whose filters as far as I know we don't eat.)

So if toxins are being concentrated in filter feeders, how does only eating a sellect part of the scallop help? I have heard from experts that the more delicious a shellfish and the less like mouse guts the edible bits look like, the less likely you are to get poisoned.

What was said above and sometimes if the mussles have released their eggs/sperm they become flabby and seperate into two halves as mentioned above. You want to eat them when they are full of eggs/sperm.

[Pan]

Is it safer not to eat it, or is it really the filter that's at issue, since bivalves feed by filtering large quantities of water and thereby absorb and concentrate whatever impurities are in the water? (And no, I'm not being alarmist or telling people to stop eating bivalves, though I limit my consumption of bivalves other than scallops, whose filters as far as I know we don't eat.)

So if toxins are being concentrated in filter feeders, how does only eating a sellect part of the scallop help? I have heard from experts that the more delicious a shellfish and the less like mouse guts the edible bits look like, the less likely you are to get poisoned.

Well, if the concentration is mostly in the filter, couldn't not eating it help?

Also, to balmagowry's point: I used to eat clams in rural Malaysia, and they have to have been pretty damned clean because the water they were filtering was pretty clean water - I knew that because I myself dug them up from the silt near the mangroves on the sides of the stream that ran near my house, and I used to wade in the estuary at the end of that stream, which was then and still is now so clear that you can completely see the bottom from the middle of it. But I'm never sure how clean the water was when I get bivalves in a restaurant. When I do order mussels, I don't eat the ones that didn't open up when they were boiled and won't eat any that taste at all fishy. Am I right to think that if you have to pry open the shell, it's better not to eat the mussel?

Adam, I'm guessing the eggs and sperm taste good and that's why you want to eat them, right?

[balmagowry]

So if toxins are being concentrated in filter feeders, how does only eating a sellect part of the scallop help? I have heard from experts that the more delicious a shellfish and the less like mouse guts the edible bits look like, the less likely you are to get poisoned.

The "select part," oddly enough, is the adductor muscle - oddly because this is a bit which in other bivalves is quite often neglected (not without reason, as it tends to be rather tough in many pf them).

What was said above and sometimes if the mussles have released their eggs/sperm they become flabby and seperate into two halves as mentioned above. You want to eat them when they are full of eggs/sperm.

No, I want to eat them whenever I get them, with or without their reproductive effluents!

Also, to balmagowry's point: I used to eat clams in rural Malaysia, and they have to have been pretty damned clean because the water they were filtering was pretty clean water - I knew that because I myself dug them up from the silt near the mangroves on the sides of the stream that ran near my house, and I used to wade in the estuary at the end of that stream, which was then and still is now so clear that you can completely see the bottom from the middle of it. But I'm never sure how clean the water was when I get bivalves in a restaurant. When I do order mussels, I don't eat the ones that didn't open up when they were boiled and won't eat any that taste at all fishy. Am I right to think that if you have to pry open the shell, it's better not to eat the mussel?

Absolutely. In fact, a mussel or clam that hasn't opened shouldn't even be served. The reason they open is that when they die the adductor muscle relaxes and no longer holds them shut; if the shell doesn't open it is best to assume the reason is that the muscle didn't relax because the mussel didn't die. Which, unless it's SuperMussel and is leaping off the plate, probably means it was dead before it went into the pot. I don't cook them if they're open (and refuse to close) while alive; I don't eat them if they're closed (and refuse to open) when cooked. BTW another reason a mussel might not open is that it isn't a mussel; occasionally a pair of mussel shells held together by black mud can convincingly fake its way through preliminary triage and even through the MusselMatic (about which I shall tell you later). When this happens you're damn lucky if they don't open while cooking. Nothing ruins a lovely delicate white mariniere sauce like a nice dollop of black muck.

Re the clean waters and safe shellfish, I couldn't agree more; as a result I almost never eat bivalves in restaurants. Not even so much because they might be unsafe (I try not to go to restaurants which have a reputation for unusually high incidence of hepatitis...), but because they will never never be anywhere near as fresh as those I have caught myself. Or as small, or as wild, or as un-overcooked. I don't catch below the legal size limits (well... occasionally a clam or two for eating raw - I just can't resist the really tiny ones), but I almost never find mussels as large as the ones served in restaurants, which I assume are farmed, and which to me seem flabby in texture and uninteresting in flavor, compared to the smaller ones I find at the edges of the salt marsh.

[EDIT: I knew I would get mussel and muscle confused sooner or later....]

Edited April 17, 2004 by balmagowry (log)

[Anna N]

Not totally off-topic, I hope BUT

Many recipes call for steaming mussels for 5-10 minutes! If I did this most of my mussels would be perfect erasers. I find that most open within 2-3 minutes and as they open I remove them from the pan. My first question is - when do I give up and accept that the unopened ones are dead? (I toss any that won't close or whose shells are damaged before I steam any) And my second question is if they do open SLIGHTLY during steaming, are they safe to pry open and eat? I never do this but my SIL does.

[phaelon56]

I have no idea whether it's a valid approach or not but I never cook or eat a mussel (or clam) that is already open before cooking and I never eat any that don't open during cooking.

And I used to work for a guy named Harry Mussel. His parents should have given more thought to the choice of name.

[jayt90]

When I take a bag of farmed mussels home from the store (usually from P.E.Is., probably 2 days old), the fishmonger puts them in a plastic bag, with ice chips, and advises me not to close the bag, as they cannot breathe, and will surely die. I have tied the bag securely, and found that a very large number of them will open upon steaming, and taste delicious with no ill effects. Is this an old wive's tale, that they must beathe air until cooked?

[balmagowry]

Not totally off-topic, I hope BUT

Many recipes call for steaming mussels for 5-10 minutes! If I did this most of my mussels would be perfect erasers. I find that most open within 2-3 minutes and as they open I remove them from the pan.

Most open even faster than that - and yes, I too take them out of the pan as soon as they open.

My first question is - when do I give up and accept that the unopened ones are dead? (I toss any that won't close or whose shells are damaged before I steam any)

Once I've got all the open ones out of the pot, I figure it doesn't much matter what I do to the rest. So I increase the heat and give them a couple of miinutes. If any open, great. I give up once I get impatient - a good rule of thumb. BTW I don't worry much about damaged shells - but again, I'm lucky in the provenance of my shellfish and can tell when the damage has been caused by me.

And my second question is if they do open SLIGHTLY during steaming, are they safe to pry open and eat? I never do this but my SIL does.

I'm with your SIL on that. Hey - open is open. If it were dead before it went in the pot the heat wouldn't have any effect at all on its adductor.

I have no idea whether it's a valid approach or not but I never cook or eat a mussel (or clam) that is already open before cooking and I never eat any that don't open during cooking.

It's valid except for one thing: when I find a mussel that's already open before going into the pot, I gently push it closed. If it stays closed, that means it's alive and responding, so into the pot it goes. If it gapes again - I toss it.

I have tied the bag securely, and found that a very large number of them will open upon steaming, and taste delicious with no ill effects. Is this an old wive's tale, that they must beathe air until cooked?

Not entirely. They do need air, but they can go a good while without it, as witness the fact that in their natural habitat they spend half of every day under water - they are, of course, able to get some oxygen from the water, but they're not taking big gulping gasps the way we would! So anyway, I wouldn't leave them in a sealed bag for a very long time - but for the amount of time it takes you to get home (assuming you live within reasonable distance), it's probably fine. I'd worry, though, about leaving them sealed for hours. How long is too long? You'll know from the smell when you open the bag....

[Adam Balic]

Obviously not eating an unopened bivalve has its merits, but not to eat a oyster is too much of a sacrifice. Or are there seperate rules for mussels and oysters? After all, you open an oyster and eat it raw so how could you know it it was ever going to open?

I haven't too much of an issue with picking mussels off rockes etc and eating them raw. I don't eat un-opened mussels once cooked as these are, well, un-opened. I suspect that at least some of the issue of not eating un-opened mussels is that before they were grown on ropes or stakes, it was possible to get a long dead mussel full of mud and grit.

Mind you I currently live in Scotland and the mussels grown on the west coast are pretty fine and from very clean water apart from the occasional radioactive contaminant.

Should you ever be on the West coast of Scotland it is well worth looking for Horse mussel (Modiolus modiolus) known as Clabbies or Clabbie Dubhs from the Gaelic meaning 'large black mouth' amoungst all the regular mussels. Different species and they grow very large, flesh is very bright orange.

Edited April 17, 2004 by Adam Balic (log)

[balmagowry]

Obviously not eating an unopened bivalve has its merits, but not to eat a oyster is too much of a sacrifice. Or are there seperate rules for mussels and oysters? After all, you open an oyster and eat it raw so how could you know it it was ever going to open?

Ah - oysters are a different thing entirely. And yes, I'll eat just about any bivalve raw (except for your mutant oversized mya arenarea ).

Why is that different? Because when you open the thing you can tell by the smell - or lack thereof - whether it's OK. If it's really bad you'll know by the smell before you get it fully open; and by what you see if you're foolish enough to continue after that point.

I am happy to say this has never happened to me with an oyster or a clam.

I haven't too much of an issue with picking mussels off rockes etc and eating them raw. I don't eat un-opened mussels once cooked as these are, well, un-opened. I suspect that at least some of the issue of not eating un-opened mussels is that before they were grown on ropes or stakes, it was possible to get a long dead mussel full of mud and grit.

Well, that's the point, for some of us. Since the mussels I get grow neither on ropes nor on stakes, but tucked into, or attached to, the edge of the salt marsh, mud and grit are a distinct possibility. Usually the triage and de-bearding they undergo before being cycled through the MusselMatic is enough to identify the ringers; if not, the centrifugal force of the MusselMatic will generally do the job. But black muck has exceptional suction power, so every once in a while we still get a tare among the wheat.

Mind you I currently live in Scotland and the mussels grown on the west coast are pretty fine and from very clean water apart from the occasional radioactive contaminant.

Damn, our local mussels don't have that latter advantage - this may explain why they are often crusted with barnacles (not the edible kind, AFAIK).

Should you ever be on the West coast of Scotland it is well worth looking for Horse mussel (Modiolus modiolus) known as Clabbies or Clabbie Dubhs from the Gaelic meaning 'large black mouth' amoungst all the regular mussels. Different species and they grow very large, flesh is very bright orange.

Hmmmm. :dubious: But how do they TASTE and how is their TEXTURE? The mussels I get here are usually very bright-orange-fleshed - small, tender and sweet. My experience of much larger ones (though admittedly not the Horse variety) has not been pleasant - flabby and less flavorful.

I'm also really starting to wonder about the correlation between your "occasional radioactive contaminant" and your HUGE MUTANT shellfish, as discussed both here and on the steamer thread. Coincidence? Hmmm??????

[Adam Balic]

You eat the smaller clabbie dubhs, you can eat the larger ones, but you have to remove the 'frill' and they are mostly wrapped in bacon and grilled or used in soup at this size. Their flavour is exceptional.

Do you know the species of your mussels? Would be interested to know. The common species in Australia is different to that in Scotland, they Scots version is much better. So sweet.

Surely most of the mussels consumed in the US are rope or stake grown? No grit or mud issue then.

Edited April 17, 2004 by Adam Balic (log)

[Mabelline]

And I used to work for a guy named Harry Mussel. His parents should have given more thought to the choice of name.

But surely that's got to be better than if they had named him Puny, Flabby, or Scrawny??

[balmagowry]

You eat the smaller clabbie dubhs, you can eat the larger ones, but you have to remove the 'frill' and they are mostly wrapped in bacon and grilled or used in soup at this size. Their flavour is exceptional.

Sounds wonderful, I must admit.

Do you know the species of your mussels? Would be interested to know. The common species in Australia is different to that in Scotland, they Scots version is much better. So sweet.

I don't know off-hand, but can probably learn. Shall try to find out. Also, when the season starts, shall hope to find (last year was a poor one for mussels, alas, but I'm hoping we're due for a good one now) and photograph.

Surely most of the mussels consumed in the US are rope or stake grown? No grit or mud issue then.

I'm sure the commercially farmed ones are - but these are wild, and their habitat is protected wetland. I do know some people who drop a rope or chain in their boat-slips - I also sometimes harvest them off the undersides of docks. But usually they are much more plentiful and accessible at the edges of the marsh.

[balmagowry]

Do you know the species of your mussels? Would be interested to know.

Looks as though what we get here is the Common Mussel, Mytilus edulis. Googled around for a picture and didn't find one that pleased me - they all look rather the worse for wear, whereas those I get here are glossy and black and beautiful. I did, however. find this page that includes a picture comparing my mussel shell with yours as to size. And actually the uncaptioned picture at the bottom of the page does look something more like our mussels, though the surface to which they cling is FAR too smooth....

Still looking for decently representative photo of their habitat - so far, no dice. Shall take some myself, if need be.

[auntdot]

Have eaten raw clams and oysters for years.

But only the hard shell variety.

I am a hardy soul. When I go to a clam bar I always tip the guy who shucks the stuff in advance to toss me the big ones.

Many would call them quahogs and not cherrystones.

I am probably eating the stuff they would toss in the chowder pot anyway, but who cares? I like them.

But with the exception of balmagowry (vide supra), I have never heard of anyone who has eaten raw soft shell clams (mya arenaria) or mussels.

And have wondered why not for many years.

Do not now live in an area where I can find soft shell clams (make a run to New England every few years where I eat them steamed and fried until I could burst), and the mussels we find in the supermarket, I would not trust to eat raw.

I can only guess that shucking a soft shelled mollusk could be difficult, and frankly, I am not sure I could pass one of those guys down my gullet.

But I would do my best.

But why, to end this bloviating, do people not serve raw soft shelled clams and mussels?

[Adam Balic]

But with the exception of balmagowry (vide supra), I have never heard of anyone who has eaten raw soft shell clams (mya arenaria) or mussels.

Many European ethnic types and their children eat raw mussles and clams. Sometimes it is the best way of eating them.

Looks as though what we get here is the Common Mussel, Mytilus edulis. Googled around for a picture and didn't find one that pleased me - they all look rather the worse for wear, whereas those I get here are glossy and black and beautiful. I did, however. find this page that includes a picture comparing my mussel shell with yours as to size. And actually the uncaptioned picture at the bottom of the page does look something more like our mussels, though the surface to which they cling is FAR too smooth....

Well the shells look like they have been banging about on the beach for a while, but the size differential is about right, although the really big horse mussels are not that common.

In Australia the common mussel species eaten is Mytilus galloprovincialis, which is very similar to M. edulis and hybridises in Europe. As I said before the mussels in Europe taste much better then in Australia, wonder if this is diet or species based?

[balmagowry]

I can only guess that shucking a soft shelled mollusk could be difficult, and frankly, I am not sure I could pass one of those guys down my gullet.

But I would do my best.

But why, to end this bloviating, do people not serve raw soft shelled clams and mussels?

Prolly 'cos they don't taste very good. They're slimy in a different way and... well, I dunno, I don't care for them. Tried it on principle, is all; don't make a practice of it - not worth it. Actually, BTW, a soft-shelled clam is the easiesy bivalve of all to open, as its shells are separated by membrane and are not shaped to fit snugly together IAC; OTOH it's a little more unnerving than opening hardshells or oysters, because a softshell has more moving parts - and it does move them.

Oh - to clarify - the above all refers to mya arenaria - it's so long since I tried a musssel raw that I can't claim to remember much about it, except that it was a pain in the ass to open, and... as I remember it wasn't bad, it just wasn't anywhere near as good as moules mariniere, which I love so much that I can hardly stand to sacrifice a mussel for any other presentation.

[balmagowry]

In Australia the common mussel species eaten is Mytilus galloprovincialis, which is very similar to M. edulis and hybridises in Europe. As I said before the mussels in Europe taste much better then in Australia, wonder if this is diet or species based?

How very odd. I can very well understand the nomenclature of mytilus edulis, in fact it's one of the most supremely edulis items I've ever been privileged to encounter. But why on earth would a mussel native to Australia be galloprovincialis? I wasn't aware of any French colonizing in those parts - does that just go to prove how ignorant I am?

I'm pretty sure the mussels in Brussels (WHY hasn't anyone written a song about this yet?) are the same variety we get here, though bigger and presumably farmed. But the fact that they look and taste similar (if a bit less sweet and delicate) proves nothing, I suppose....

[Adam Balic]

Well originally they were identified in the Mediterranean, rather then M. edulis which was more common in the Atlantic. It is now known that the two species hybridise readily, so mixed populations commonly exist.

The exact species in Australia is was/is a matter of debate, it was thought that Mytilus galloprovincialis may have been introduced from Med post-European settlement, but shells of the species have been found in pre-settlement Aboriginal middens. This suggests a much wider distribution then was orginally thought.

I personally would like to see more data, before and definative labels were applied, it would be very interesting to know how different the Australian mussels are to the European.