Could you please tell me how long salt cod will keep in the package from the supermarket? And how long if it’s frozen? — Hugh M.
Spoilage is a result of bacteria or mold feeding on proteins and fat in the presence of moisture. Water is the key issue here. Salt cod is 80% protein and contains practically no water or fat, so if kept in a dry place, it won’t spoil for very long periods. It has been stored on long sea voyages — and kept in hot, dry climates — without refrigeration, for centuries. (I hasten to add that individual pieces of salt cod haven’t been kept for centuries, but that the method of salting and storing has been used for centuries, although you might think that some fish are that old when you’re trying to soak them!) Additionally, the high salt content kills bacteria by increasing osmotic pressure within the bacterial cells, bursting them.
As long as salt cod is kept dry, it ‘s unlikely to spoil. Freezing shouldn’t affect the longevity of the product, but because of the high salt content, the fish might not even freeze — so it’s unnecessary.
If you’re concerned about the quality of a particular piece of salt cod, look at the color: It should be nice and white. Reddish or yellowish salt cod has been affected by microorganisms and/or oxidation and will have off flavors.
If you haven’t read Mark Kurlansky’s book Cod: A Biography of the Fish that Changed the World ,you might find it interesting. — Gary Allen
Article © 2008 Gary Allen. All rights reserved. Visit Gary’s Web site, On the Table.