Good question. I've heard that lobster is also such a case in the US. Originally, for the English colonizers and subsequent immigrants, lobster was considered a filthy bottom feeder, was thus not eaten by the men of means and fed to prisoners since it was in abundance in the North East.

Ahh, Cracked has an article: http://www.cracked.com/article_17246_when-lobster-was-spam-5-gourm et-foods-that-used-to-be-cheap.html

We're assuming Cracked is a reputable source, right?

Gulf of Maine Research Institute says similar http://www.gma.org/lobsters/allaboutlobsters/lobsterhistory.html

Same with oysters. Formerly poor-people food, now a fancy food.

The last resort (OK, second-to-last resort) of the Jamestown colonists was to go out and gather oysters at low tide. Oysters being almost everywhere, but looked at as a worthless food source.