By ERICA MARCUS
Q. When milk approaches its stamped expiration date, will it continue to deteriorate if used in a cooked item?
A. No, your pudding will be safe, said Kathryn Boor, a professor of food science at Cornell University who specializes in dairy microbiology. Boor explained that it is bacterial growth that causes milk to "go bad."
Cooking, however, "stops bacterial growth in its tracks." Boor said that "you're not going to get rid of any off flavors that are already there," but you will restart the bacterial clock from the time you cook the milk.
In fact, you can restart that clock without bothering to make the pudding by simply bringing milk to a boil and then storing it in a clean container, i.e., not back in the original carton.
Boor said that milk's fat content has no effect on how quickly it goes bad.
Since I had her on the phone, I asked Boor about milk that was past its sell-by date but still smelled fine. "The beauty of the current U.S. dairy system," she said, "is that it is very, very safe." She said that the sell-by date was principally of benefit to milk retailers: They can't open up every carton they stock; the sell-by date assures them that their customers aren't buying milk on its way to spoiling.
When I asked her if it was safe to drink milk that was beyond its sell-by date but still smelled fine, she said "no one can say for sure, but you probably can."
Q. Confectioners' sugar is often labeled "10-X." Ten times what?
A. It's not 10 times anything, said Jeff Robinson, technical director of American Sugar Refining Inc., which manufactures Domino sugar. Rather the "10" refers to the level of pulverization inflicted on the granulated sugar to make it powdered. "I don't know where the "X" convention comes from," said Robinson, "but 10-X is the name we give to pulverized sugar when 97 percent of the particles will pass through a 200-mesh screen." A 200-mesh screen is a screen that has 200 holes per inch, each of which measures 74 microns across.
Domino also sells 4-X and 6-X sugar, which are coarser powders, and a 12-X sugar, which is finer.
What is the advantage of smaller particles of sugar? "The smaller the crystals," Robinson said, "the more rapidly they dissolve in water." Confectioners, who may well want to whip up a batch of frosting, rely on fast-dissolving sugar.