Experts' Expert: Cheese Management

From Cooks' Illustrated comes the following Q&A with Mary Keith, food and nutrition agent at the University of Florida Extension Service.

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How to Deal With Moldy Cheese

Q. Aside from cheese that contains cultivated mold [Cabrales, Gorgonzola, Roquefort, Stilton et al], is it safe to eat cheese that has grown mold as long as I first cut off the affected area?

A. According to Keith, hard cheeses can generally be salvaged, but soft cheeses cannot.

The toxins in the types of mold that grow on cheeses are mostly water–soluble, so they usually cannot travel far beyond the surface of harder cheeses with low moisture levels.

To remove surface mold from a hard cheese such as cheddar, the general rule is to cut off all visible mold as well as an inch of the surrounding area, being careful to keep the knife out of the mold itself to prevent cross–contamination of other areas of the cheese.

Of course, this works only if you have a big piece of cheese.

Small pieces on which the mold has grown on multiple sides should be discarded.

Soft cheeses such as goat cheese, Brie, or Camembert and wet, curd–like cheeses such as ricotta or cottage cheese should never be consumed once mold appears.

Because most of the toxins produced by these uncultivated molds are water–soluble, they can easily travel beneath the surface of these high–moisture cheeses and contaminate the rest of the product.

Cheeses that are injected with mold, such as blue cheeses [top], should be discarded once they start becoming slimy or softer than usual or exhibiting strange odors or colors.

My advice is never to buy more cheese than you can use in one or two weeks; the moister the cheese, the quicker it will spoil.

As for storing most leftover cheese, I have found that wrapping it in parchment paper and then in foil is the most effective method, but a sealed zipper–lock bag is a very close (and much easier) second.

Whichever method you choose, the cheese is best kept in the crisper drawer of the refrigerator.

One more thing: Freezing doesn't kill mold.

While freezing might slow down the mold's growth, it will not destroy any of the toxins the mold has already produced.

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I recall my introduction to soft cheese management, back when I was in college: I loved Camembert and Brie but after a couple days I'd notice a sharp ammonia smell when I opened the package: that was a sign that was obvious even to me.