I was surprised to hear that some luncheon meats contain milk derivatives that aren't declared on the ingredients list. I rarely buy these products. But when I do I read the labels carefully, since I have a severe milk allergy. Now I worry that I can't rely on the labels to tell the whole story. Can milk derivatives really be present even if they're not listed?ANSWER - Until recently they could. Indeed, three episodes of severe allergic reactions in milk-sensitive individuals who ate hot dogs or bologna were reported not long ago in the New England Journal of Medicine. Unfortunately, the product had been reformulated to contain partially hydrolyzed sodium caseinate, which was not listed on the label.

At the time, the manufacturer wasn't violating any regulation. Until now, additives such as sodium caseinate, which is commonly used as a binder in processed foods, could be included under the umbrella term "natural flavorings." A change in the U.S. Department of Agriculture regulation became effective last September requiring that sodium caseinate, as well as certain other additives used in processing meat and poultry products, be listed on labels.

Since you do have a severe milk allergy, you should know that only foods containing 2 percent or more of meat or poultry are covered by this regulation. Other processed foods, under Food and Drug Administration regulation, still permit sodium caseinate to be listed under a general "flavorings" category. So until more stringent rules are put into place, it's best to get in touch with the manufacturer before using any products about which you have doubts.

QUESTION - Recently, after a buffet supper, more than half the chicken breasts I'd prepared were left over. I don't have much freezer space and I didn't want to take a chance on safety so I gave most of the chicken to my guests to take home. If I miscalculate again, how long can I store leftover cooked chicken in the freezer?

ANSWER - It will remain at top quality for three or four days. After that, changes in both flavor and texture will start to develop.

As with other cooked meats, however, we cannot emphasize too strongly that to ensure that the chicken is safe, you must handle it very carefully. This means using a clean container for storing it and refrigerating it promptly, preferably as soon as everyone has been served a second helping.

If you're saving a large roasting chicken or a turkey, it's also a good idea to remove the meat from the bones before you put it away. This will promote prompt, even cooling of the meat.

QUESTION - I know that dried beans are among the better sources of soluble fibers, the type that seems to help lower serum cholesterol. I hadn't eaten them much until a recent visit to Central America, where I ate rice and beans twice a day. I found I enjoyed them and now that I'm home I want to work them into my diet. The question is, what type should I buy? Which ones will give me the most fiber?

ANSWER - Fiber content does vary among types of dried beans, but the differences aren't that great. You'd probably be better off choosing your beans on the basis of taste preference, and using different kinds to add interest to your meals. At the high end of the fiber spectrum, a cup of navy beans contains more than 41/2 grams of soluble fiber, with pinto beans following closely behind. White beans are at the low end, providing almost 3 grams. As a side note, there is less soluble fiber in lima beans, chickpeas and blackeyed peas. Also, measure for measure, dried beans you cook yourself are likely to contain more soluble fiber than the canned variety.

You asked specifically about soluble fiber, but we should point out that dried beans have another fine feature. They are also rich in insoluble fibers, which are linked to normal bowel function. Going back to our example of navy beans, the total fiber content of one cup is 131/2 grams. Of that, about 60 percent is insoluble fiber, and about 40 percent soluble.

1991, Washington Post Writers Group