CONSUMERS AND THE federal government are scrutinizing food labels these days, and it's not to figure out how much food costs.

Consumers complain that the labels are confusing, while the Food and Drug Administration finds that changing them is difficult. But changes are taking place -- and even bigger changes may be in store.

Under consideration at the moment is nutrient labeling -- a list of key nutrients found on some food packages. Consumer advocates assert that current nutrient labels and useful only to the government, as tools to investigate industry claims of certain nutrients. Bonnie Liebman, nutritionist at the Center for Science in the Public Interest, cites cereal nutrients as a good example. Cereal manufacturers list sugar contents in grams per ounce, a description that has very little meaning to the average consumer. The FDA is accepting suggestions for labeling alternatives until Jan. 31 before making a formal proposal to change nutrient labeling (see related story on H2).

But nutrient labels are just a small part of food packages; there are other sources of confusion. Of the 2,800 substances that are added to foods, for example, some sound highly processed, but are natural (alpha tocopherol is really vitamin E, an effective antioxidant). Others sound familiar but are totally synthetic (vanillin -- an artificial vanilla flavoring). Still others, such as texturized vegetable protein (from soybeans) or sugar, are derived from natural sources, but critics maintain they are too highly processed to be called natural.

While labels are confusing, they are too important to ignore. They can help the consumer determine amounts of cholesterol, sodium or calories; identify the presence of highly processed or sugary foods; and indicate maximum nutrition per food dollar.

Clearly, labels have a lot to offer in these health- and money-conscious times. To illustrate how to decipher food label regulations we have "manufactured" Catfish Fixin's, a complete dinner package of side dishes, condiment and cornmeal coating for catfish (not included).

NAME AND LOCATION OF MANUFACTURER, PACKER OR DISTRIBUTOR

MACARONI AND CHEESE: enriched macaroni, pasteurized process cheese spread (cheese [American hard cheese], water, whey, hydrogenated vegetable oil [includes one or more of soybean, cottonseed or palm oil], sodium phosphate, salt, sodium alginate, artificial color).

Enriched macaroni: Manufacturers of wheat flour products usually replace some of the B vitamins and iron lost during processing. While enrichment is voluntary except in those states specifically requiring it, when a product is labeled enriched it must follow federal standards for nutrient levels. Because macaroni meets a "standard of identity" [see catsup], its ingredients need not be listed. Whey: is left over when protein and fat are removed from milk to make cheese; it contains a little high-quality protein and some milk sugar. Hydrogenated vegetable oil: Usually several oils are named because their prices vary, and producers want freedom to choose among them. While soybean and cottonseed oils are unsaturated, palm oil is saturated and not recommended for some special diets. Sodium alginate adds body, what manufacturers call "mouth feel." Sodium phosphate contributes to characteristic sauce texture by helping to bind the cheese and water. These two additives, like salt, should be watched in sodium-restricted diets. Artificial colors and spices need not be itemized.

PORK & BEANS: prepared pea beans, water, tomatoes, corn syrup, sugar, pork, salt, distilled vinegar, natural flavoring, citric acid and spices.

Ingredients are listed in descending order of weight; therefore, it contains more sugar than pork. Although corn syrup and sugar are listed separately, combining them could place sweeteners higher on the list of ingredients, as is often the case in cereals. Common sweeteners include white sugar, brown sugar, molasses, honey, maple and corn syrups and the "oses" -- glucose, fructose, lactose, dextrose and maltose. Citric acid acts as an antioxidant (preservative) to prevent rancidity. Other common preservatives are TBHQ, BHA and BHT.

REG. PENNA. DEPT. OF AG.: All baking plants (including those making macaroni and spaghetti, pretzels and potato chips and snacks from cornmeal) with sales in Pennsylvania must be licensed by the state and inspected annually. Many manufacturers with national distribution mark all packages rather than single out those to be sold in Pennsylvania.

NET CONTENTS OR WEIGHT. For food consumed without liquid (e.g. olives), drained weight is usually indicated. When weight includes liquid, the container must be as full as practical.

"NATURAL," whether in terms of content or processing, eludes legal definition. Laboratories cannot distinguish natural chemicals from synthetic -- for example, whether or not the vitamin C was derived from oranges. Also, additives some might call unnatural may be from natural sources, as with carrageenan, a thickening gum obtained from seaweed. A vegetable oil could be considered natural in its liquid form and not in its solid (hydrolized) state. And "natural" cheese made by traditional methods could contain artificial color or flavor. PRODUCT NAME

COMBINATION FOODS: Names of foods such as macaroni and cheese must reflect contents in descending order of weight. "Cheese and macaroni" would have to contain more cheese than macaroni. An exception for "historical usage" is made for pork and beans, "because the identity of the product has been understood by consumers for years and years," says the FDA.

CATSUP: Familiar foods meeting common "standards of identity" require no ingredient labeling. No deviations are allowed. Because catsup standards include salt, low-sodium catsup would have to be labeled "imitation."

NUTRIENT LABELING: Only products to which nutrients have been added, or which make a nutritional claim (e.g., "improved nutrition," "reduced calories," "low cholesterol," "low fat"), must have complete nutrient labeling. That includes total calories, fat, protein and carbohydrate per serving, plus the percentage of RDA of eight nutrients. Other nutrients may be listed if product contains at least 2 percent of the RDA. Some manufacturers voluntarily list nutrients.