As a cheesemonger, I can't help but wonder about the origins of this great, unspoken assumption, and who among us actually abides by it? And regardless of whether or not you have an opinion one way or the other on the matter, you probably can't deny that the topic can be very heavily and hotly debated.
There are several explanations for the traditionally Italian mentality to keep cheese far away from fish dishes:
• Most fish has a delicate, mild flavor. Fish should taste of the sea, and should be consumed as close to the catch as possible to ensure this. And it should be served simply, for the same reason. The rich, salty flavors of cheese can too easily overwhelm the flavors of fish, forcing a contrast not only in intensity of flavor, but also a sacrifice of the integrity of both ingredients. Grated cheese over a fish pasta is considered either extraneous, excessive, or demeaning.
• It's very possible that tradition has dictated this rule more than anything else. Great Italian cheesemaking regions like Emilia-Romagna, Piedmont, and Lombardy are largely — if not completely — landlocked, making them conducive to dairying, while Liguria, and Puglia, whose cuisines are largely fish-focused, are coastal. You could say that form follows function in this case, in the same way that in wine and food pairings, often what grows together goes together.
• There may actually be historical reasoning behind this largely-accepted rule. For many centuries, meat and dairy consumption were forbidden for religious reasons on every Friday. On that day, fish became the logical replacement for meat, and since cheese was also restricted, the two foods evolved distinctly from one another. A possible explanation.
• There are many exceptions to the "rule," and I'm sure many of us are "offenders." Anchovies on pizza is something that comes immediately to mind, although I'm not sure how popular this is in Italy. And I did find a recipe for a pasta with anchovies and parmigiano reggiano by Marcella Hazan, an exceptionally headstrong authority on traditional Italian cuisine. Sicily and Sardinia both have very strong cheesemaking traditions, despite their seaside geography.
Any cheese-loving thoughts on this matter? Do you quell or indulge your temptation to top your linguine alle vongole with pecorino?