DEAR DR. BLONZ: I am interested in your thoughts about my new method of storing sour cream in the fridge. After it has been opened, I put the top on tightly, but store it upside-down to prevent air from getting in. I keep the inverted container on a small plate to keep drips from making a mess on the refrigerator shelf. I can't tell you exactly how much this increases the storage life, but I haven't had to throw out any sour cream since I started doing this. -- L.S., San Francisco
DEAR L.S.: Air exposure is what needs to be controlled. Lids should provide a good seal after the inner liner has been removed prior to the first use. Turning the container upside-down in the manner you describe might make a better air seal, but there is that increased risk of leakage, and that could represent a tradeoff. Odors or other contaminants could be picked up and passed back to the sour cream using the seeped liquid as its conduit. The priority should be buying the right size container for your typical use pattern.
DEAR DR. BLONZ: Are canned beans as nutritious as dry beans? The canned kind is more expensive, but less work. -- C.C., Baton Rouge, Louisiana
DEAR C.C.: Canned beans are just as nutritious as the dry kind. Many commercial products have added salt, but giving the beans a fresh-water rinse will remove a lot of that sodium. There are also low- and no-salt varieties available.
DEAR DR. BLONZ: Isn't it a bit misleading for foods to claim to be "nonfat" when they can contain large amounts of sugar? Doesn't sugar just become fat in the body, anyway? -- T.T., Sacramento, California
DEAR T.T.: The body has a constant need for energy, but we eat only a few times per day. We typically take in more energy and nutrients than we need at the moment, so our human machine has a finely tuned ability to put excess calories away until needed. A very small amount of carbohydrate is stored in the form of glycogen, but the vast majority gets stored as fat -- the most concentrated form. Food labels deal with what is in the food, not what happens once it is in the body.
DEAR DR. BLONZ: I am a cat owner and know that taurine is essential for cats. But I keep seeing it in energy drinks, and wanted to know why. -- S.H., via email
DEAR S.H.: Taurine is a compound known as a sulfonic acid. You are correct that it is needed by cats, but it's not essential for healthy human adults, as our bodies are able to make what they need. (One exception is that there is preliminary evidence that high levels of taurine may provide some benefit for individuals suffering from congestive heart failure.) The presence of taurine in energy drinks lacks scientific justification, as it is the caffeine in these drinks that provides the kick. It is unclear what taurine provides aside from "curb appeal," especially given the small amounts present.
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