DEAR DR. BLONZ: I have a follow-up suggestion to the recent column on storing bread in the freezer. Like the previous letter-writer, I live alone, and I like to cook and freeze leftovers in single-serving portions. With my bread, I usually double-wrap the loaf: I put the original package in one of the larger plastic sleeves that come with the daily paper, then twist-tie it shut after making sure all the air is out of the bags.
Now for my question: Does freezing milk affect its quality or safety? I balk at paying almost as much for a quart of milk as I do for a gallon. I have a lot of freezer space, and have been freezing milk in quart mason jars. I’m especially careful to leave at least two inches of space at the top, between the milk and the lid, to allow room for expansion of the liquid as it freezes. If you violate this principle, I’ve learned, the glass jar is likely to crack. Is milk safe to drink after having been frozen and then thawed slowly in the refrigerator? -- J.W., Tucson, Arizona
DEAR J.W.: Your bread-freezing technique sounds great. It is always gratifying to find second-generation uses for the serviceable plastic bags that come into our possession.
Freezing is a safe and acceptable way to store milk. Changes in nutritional value are negligible, but there may be a few minor changes in the way the milk appears and tastes. The freezing process can cause a breakdown in the homogenization, which is the process that distributes the milk fat evenly throughout the milk. Of course, this will not be an issue with nonfat milk; with other types, however, an occasional drop of fat may be seen floating around. Give the milk a good shake before drinking.
The taste and appearance changes depend on the speed at which the milk is frozen. A slight change in taste, and/or some loss of color, is possible. These are very minor changes, and the milk remains a wholesome food. A good rule of thumb is: the faster the freeze, the smaller the damage.
I recommend that you put your well-sealed containers next to the freezer wall or on a metal shelf, where they’ll freeze quickly and remain solid for the duration of their storage. Remember, also, that because milk is a rich source of nutrients, it provides an ideal food for bacteria and other microorganisms. Pasteurization helps destroy most, but not all, of the bacteria present at bottling. Freezing doesn’t destroy microorganisms, it just suspends or slows their growth. Keep in mind that the quality of a defrosted milk, or of any other frozen food, will be no better than it was at the time it was frozen.
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