I’ve been led to believe, by cookbooks and cooking show hosts, that seafood spoils very rapidly. It’s not uncommon to hear that I should cook seafood the day I buy it, or at the most within three days. Yet my beef (and pork and chicken) often has “Use by” dates a week out. That’s not even including “aged beef” or things like venison, which I understand are left out hanging for weeks before being cooked sometimes.
Is this impression accurate? If so, why? What is it about seafood physiology that makes it more prone to spoilage levels of bacteria in a very short amount of time compared to other meat? Does it have anything to do with it being cold blooded? Do insects and caterpillars spoil quickly without cooking?
As I understand it, their cold blooded anatomy combined with the fact that many of the creatures we commonly eat routinely live at just a few degrees above freezing mean that their bodily enzymes have to function at extremely low temperatures. Put a beef steak in the fridge and the enzymes inside mostly shut down. Put a tuna steak in the fridge and the enzymes inside are still active, breaking things down and causing spoilage.
And the Alpha Twit’s explanation also holds true for bacteria and parasites. Most bacteria that would spoil a piece of beef thrive around room temperature or body temperature. A fish is pre-inoculated with bacteria that will rapidly decompose flesh at low temperatures.
McGee as a source of this info makes sense to me. Somewhere in the back of my mind, I think I heard this data from Alton Brown’s Good Eats and he often uses McGee as a source.
Crustaceans (lobsters and crabs) are supposed to be kept alive until you are ready to eat them. I would guess that otherwise bacteria would rapidly spread, but I don’t really know. What’s the straight dope on this?
That’s enzymatic action too. The meat degrades very quickly after the lobster or crab dies, and becomes mushy & crumbly. I once caught two lobsters (OK, the guy I was with caught them), one of which was a monster. By the time we got them home, we found that the large one had cracked open the carapace of the smaller one, killing it. We cooked them both, but the meat of the smaller one was inedible - tasted funny, and just crumbled apart as you took it out of the shell. It was no more than 2 hours from catch to pot.
Can’t provide scientific confirmation of this, but I’ve been told that decomposition (or maybe excess bacterial growth) can occur in shellfish before they are all the way dead. This leads to the idea that you shouldn’t cook a dead lobster. But that applied to shellfish that were kept at room temperature, not refrigerated. I’ve seen several references that a lobster kept below 40 degrees can be cooked and eaten safely for up to 48 hours after it dies.
As for the rest of fish, I’ve seen an explanation for rapid decomposition, but don’t recall the details. The enzyme explanations sounds about right though. It’s what makes aged beef taste better, chicken too according to some, but turns fish into mush. Something also about the way the meat oxidizes differently. I hope a biologist posts on this thread or the other one about food-borne illnesses. I’d like to hear the SD on this subject.