Marlene Parrish - What Einstein Told His Cook 2

8.Remove the cheesecake from the oven, and let it cool in the pan on a wire rack. Cover the pan with plastic wrap and refrigerate for at least 6 hours or up to overnight.

9.To serve, run a knife blade between the pan sides and the cake to loosen the edges, then unclasp and remove the pan sides. Cut the cheesecake into wedges.

MAKES 10 TO 12 SERVINGS

RE: BRIE

What does the “%” sign signify on the label of a Brie cheese? I’ve frequently seen cheese for sale marked, for example, “Brie—60%.”

It is the percentage of fat in the cheese, but expressed on what a chemist would call a dry weight basis —the percentage of fat in what would remain after all the moisture were removed.

In your example, the famous and ancient (eighth-century) French soft cheese called Brie, after a region east of Paris, can be made from milk and cream mixtures of various butterfat contents, resulting in cheeses containing various percentages of fat. The fat content of most cheeses is detailed on the packaging as a percentage of butterfat in the dry matter of the cheese.

Cheeses contain differing amounts of moisture, even in different batches of the same cheese. So if we want to express the percentage of fat in a cheese—the number of grams of fat per 100 grams of cheese—what should we use as the 100 grams of cheese, moist cheese or dried cheese? Obviously, the result will be more accurate and meaningful if we eliminate the varying amounts of moisture and report the percentage of fat as a percentage of the dry material.

Thus, a sample of the cheese is heated in a laboratory oven to remove all moisture, leaving mostly dried protein and fat. Then the amount of fat is measured and expressed as a percentage of the dry matter. That number will be larger than the percentage of fat in the whole (un-dried) cheese.

For example, let’s say that a whole, moist Brie is 20 percent water. A hundred grams of it would dry down to 80 grams of dry matter. If that 80 grams of dry matter were then found to contain 40 grams of fat, the cheese would be labeled “50% fat” (40/80). But that’s 40 grams of fat in what was originally 100 grams of whole, un-dried cheese. So the whole, moist cheese is actually only 40 percent fat (40/100).

The fat-percent labeling isn’t a dodge to make the cheese seem to have more butterfat than it does. Because the water content of all foods can vary so much from sample to sample, food scientists are in the habit of drying their samples first to eliminate the water and then expressing their composition on a dry weight basis. That’s standard practice in expressing the compositions of many other materials that can have varying moisture content.

Mineral water?

Purveyors of certain “gourmet” (read expensive) sea salts boast that their product contains so many “healthful minerals” that it is only 85 percent sodium chloride. The dodge is that their salt hasn’t been thoroughly dried and the other 15 percent is mostly water. On a dry weight basis, their salt would be more than 97 percent sodium chloride, just like all other salts approved for human consumption.

CHEESEMAKER, CHEESEMAKER, MAKE ME A CHEESE!

I am an apprentice cheese maker. When making Camembert we add Penicillium candidum (or some other form of penicillin) to the milk or spray it on the outside. My mother is allergic to penicillin but has never had a reaction to my Camembert. Why? Also, U.S. regulations require that the milk in cheese be pasteurized or that the cheese be aged for at least sixty days. I know pasteurization gets rid of bad bacteria such as listeriosis or brucellosis (which my grandmother called undulant fever), but how does aging get rid of them?

First, we have to straighten out some terminology. You’re confusing the bacteria with the diseases they cause, the drug with the mold, and the mold with the allergen—the substance that triggers allergic reactions in some people. Here’s the straight scoop:

Penicillin (not penicillium) is the name of the drug.

Penicillium (not penicillin) is the genus of the mold that produces the drug.

Listeriosis and brucellosis are diseases caused by bacteria, not the names of the bacteria themselves.

The drug. The oft-told story of the “wonder drug” penicillin goes back to 1928, when the Scottish physician-bacteriologist Alexander Fleming took a vacation from his work at St. Mary’s Hospital in London. He returned weeks later to find that some spores of the mold Penicillium notatum had drifted into his laboratory and settled on one of his cultures of the pathogenic Staphylococcus aureus bacteria. (Fleming reportedly ran a rather sloppy lab and habitually left uncovered culture dishes out in the open.)

He noticed that the bacteria refused to grow near where the mold colony was growing, and surmised that the Penicillium mold was releasing some kind of antibacterial substance. He named the substance “penicillin” and won a Nobel Prize for it in 1945. (Advice to aspiring Nobel laureates: Keep a sloppy lab and take long vacations.)

Today, penicillin is produced on a large scale by “farming” the mold spores of Penicillium chrysogenum , a more prolific penicillin producer than P. notatum , in steel tanks, feeding them on “corn steep,” a carbohydrate-and nitrogen-rich waste product of the wet-grinding of corn in making cornstarch.

It’s important to understand what your mother is and is not allergic to. She is allergic to the chemical penicillin itself (formula R-C 9H 11N 2O 4S, where R represents one of several atomic groupings), not the P. chrysogenum mold. The Penicillium molds used in cheese making do not generate penicillin, so they pose no problem for anyone who is allergic to the drug.

The molds. Molds are fungi that grow on moist, warm organic matter. As mycophiles (mushroom lovers) well know, there are good guys and bad guys among the fungi. Even some of the Penicillium species produce toxins that may make a food inedible or dangerous. For example, the bluish-green mold that makes your over-the-hill foods look like Chia Pets is a Penicillium . But penicillin it is not. So throw away all moldy food, along with any nearby food that may have been exposed to its airborne spores. Don’t run your kitchen like Fleming ran his lab.

Several different Penicillium species are used in making cheese, either by injecting the mold culture into the cheese (interior-ripened cheese) or by coating the cheese rounds with the mold (surface-ripened cheese). The molds contribute good flavors and impart a soft “bloom” to the cheese surfaces. Among the species most commonly used are P. camemberti for Camembert; P. glaucum for Gorgonzola; P. candidum for Brie, Coulommiers, and several French goat cheeses, and P. roqueforti for Roquefort, Danish blue, and Stilton.

The bacteria. Bacteria, of course, can also be good guys or bad guys. Among the common black-hat, pathogenic bacteria are Listeria monocytogenes and certain members of the genus Brucella . The symptoms of infection by these bacteria are called listeriosis and brucellosis, respectively. Brucellosis goes by several different names—Malta fever, Mediterranean fever, Cyprus fever, etc.—depending on the part of the world in which the various Brucella species have caused the most trouble. (The name undulant fever comes from the fact that the fever chart of a brucellosis sufferer undulates up and down as the days go by.)