Nutrition Hotline
Proper Handling of Tofu
QUESTION: I've seen it recommended that you should only choose commercially-sealed packages of tofu, since the open, unrefrigerated trays of water invite bacterial growth. However, it's also said that all tofu, even if packaged, should be cooked adequately (internal temperature of 160 degrees) to kill any bacteria. I teach cooking classes in which we use tofu in smoothies, desserts, spreads, and so on, and the tofu is not cooked. Is this an unsafe practice?
Margaret P., Via e-mail
ANSWER: Not necessarily. The tofu that comes in the 12.3-ounce, aseptic packages (they look like small bricks) is sterile due to the manner in which it is processed. In fact, aseptically-packaged tofu, such as Mori-Nu brand, doesn't need refrigeration until the package is opened. For purposes of food safety, this is the most practical and safest form of tofu to use. Once you open the package, however, you should handle tofu with clean hands and leave it unrefrigerated no longer than necessary. If you've handled the tofu properly, there's no need for additional cooking.
Tofu sold in sealed plastic tubs of water is not sterile and must be refrigerated at all times. There's a greater food safety risk when using this type of tofu, so keep it refrigerated and use it promptly after purchase. A potential problem is when stores overstock refrigerator shelves with this type of tofu, causing the packages at the top of the pile to be inadequately refrigerated. Much more worrisome, however, is tofu sold in bulk bins, where blocks of tofu are kept in a bin or barrel of water and customers fish out what they need. Tofu sold this way is the most likely to be contaminated.
My recommendation: if the tofu is being used in uncooked foods, use a brand that is aseptically packaged. In foods that will be cooked, use whichever type of packaged tofu you prefer. I generally recommend avoiding tofu from bulk bins unless you take care to handle it carefully and cook it well.
How Long is Juice Fresh?
QUESTION: I juice carrots and apples, but it's inconvenient to do it daily. How long will the juice retain vitamins and minerals if I make it days in advance?
Bill, Via e-mail
ANSWER: Some nutrients do deteriorate over time as the juice is held. Even with some nutrient loss, though, fruits and vegetables are still highly nutritious. A bigger concern about making quantities of fresh carrot and apple juice ahead of time is spoilage. Carrot juice, in particular, keeps for a relatively short period of time before spoiling in the refrigerator — sometimes as little as two or three days. It's best to drink fresh juices as soon as possible. If you must prepare juice in batches, then freeze what you don't use and thaw it as needed. You may find, however, that freezing and thawing is no more inconvenient than simply taking the time to make it fresh daily.
