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Foods

Milk
Why Eat It
Varieties
Shopping
Storage
Preparation
Nutrition Chart


Why Eat It

Milk, the foundation for all other dairy products, is in itself an exceptional food. Rich in high-quality protein, milk is also a preeminent source of calcium. In addition, it supplies vitamins A and D, riboflavin, other B vitamins, and phosphorus. For years, whole milk was considered the healthy standard, a requisite for robust children and a beverage adults were encouraged to continue drinking after childhood ("you never outgrow your need for milk" ran the advertising jingle). Between 1970 and 1990, however, whole milk consumption steadily declined, dropping more than 50%, as weight- and health-conscious Americans, learning the harmful effects of dietary fat and cholesterol, begun to question the value of the all-American drink.

Yet as whole milk consumption was dropping, reduced-fat, low-fat, and skim milk were increasing in popularity: Today, Americans drink more milk in these three forms than whole milk. Fortunately, when its fat content is reduced, milk's other nutrients actually increase. The most important one, perhaps, is calcium, and milk is the leading source of this mineral in the American diet. Calcium is nearly as important for adults as it is for children, since the body is continually replacing bone over a lifetime. Although calcium occurs in many other foods, including green leafy vegetables, it is in its most usable form in milk. Just 2 cups of skim milk a day provides 50% of the adult Daily Value for calcium--for under 200 calories. A fair amount of phosphorus, which works in balance with calcium to build bone, is another of milk's nutritional assets.

Like meat, milk provides high-quality protein, and it is very well balanced in its amino acid makeup. Yet unlike the protein in many meats, the protein in low-fat and skim milk does not come packaged with fat. Milk is particularly high in the amino acid lysine, which is limited in many plant foods, especially grains, making milk an ideal complement to cereals, bread, and other grain products.

All milks are required by the FDA to be fortified with vitamin A, a fat-soluble vitamin that is largely lost when milkfat is removed. And all milk is fortified with vitamin D, which is present naturally in milk in small amounts. A deficiency of vitamin D can interfere with the body's absorption of calcium, leading to rickets, a disease characterized by bone malformation that affected many American children in the early 20th century. Adding vitamin D to milk has been credited with the virtual elimination of rickets in this country.

The words "pasteurized" and "homogenized" are so commonly seen on milk cartons that most people probably think these two processes are required by federal law. In fact, pasteurization--heating milk to destroy disease-causing bacteria, as well as yeasts and molds--is required for Grade A milk sold in interstate commerce, but within each state or locality, compliance is voluntary. Most parts of the country do comply with the pasteurization guidelines set by the U.S. Public Health Service and the FDA, so that 99% of all milk sent to market is pasteurized.

Unpasteurized, or raw, milk is considered an unsafe food product. Pasteurization not only ensures the safety of the milk supply, but also increases its shelf life. At the same time, it doesn't significantly affect the nutritional values of milk.

Homogenization, which distributes the milkfat evenly through the milk, is another process we take for granted. It was developed around 1900, but until the mid 1950s it was common for milk to arrive at stores and households with a layer of cream at the top of each bottle. You could skim off the cream and use it separately, or shake the bottle to remix the cream with the milk.

Today, almost all fluid milk is homogenized by forcing it through a small opening under high pressure. This breaks down the fat into particles so tiny they remain emulsified in the milk rather than floating to the top.

For some people, the lactose in milk is a problem, not a benefit. Lactose consists of two chemically combined sugars, glucose and galactose. Many people cannot digest more than a small amount of milk because of a deficiency of lactase, an intestinal enzyme that breaks lactose into its two constituent sugars to render it absorbable. Humans produce peak amounts of lactase in infancy, when milk is necessary for survival; thereafter, the supply begins to diminish. Many adults are unable to drink milk or eat dairy products without symptoms such as gas, bloating, diarrhea, and cramps. Lactose intolerance affects 5% to 10% of Americans of northern European origin; it is more common among African Americans, Asians, Jews, some Mediterranean and Hispanic peoples, and Native Americans.

Still, millions of people like milk and other dairy products, and want to continue enjoying them throughout their lives. Most lactose-intolerant people can eat at least some dairy products as part of a meal but not alone; most can even drink a full glass of milk with meals. Cultured dairy products with active bacterial cultures (as in some yogurts) are easier for lactose-intolerant people to digest, because the bacteria convert the lactose into the digestible sugars.

Lactase-treated milk is sold in many supermarkets, and lactase is also available in a liquid form that can be added to dairy products. To use one of these products you must add it at least 24 hours before eating the dairy products, to give it time to act on the lactose. Lactase is also available as tablets to be taken with dairy products, but these are quite inefficient.

Varieties

Buying milk is no longer a question of telling the milkman to leave one bottle or two. Not only is the milkman almost a thing of the past, the local supermarket may carry 10 or more different types of fresh milk, as well as canned and dried milk. There are milks and creams with different fat contents, with various components added or removed, and others that are flavored to appeal to a variety of tastes. Although most milk is sold fresh for immediate consumption, some forms of dairy products are processed and packaged for the pantry shelf.

Milk solids: These consist of milk's protein, carbohydrates, minerals, vitamins, and, sometimes, fat--everything but the water. They may be added to standardize the milk-solid content of milk from different sources. These solids add protein to any type of milk, and lend opacity, body, and flavor to low-fat and skim milk. Milk is graded according to its quality and intended use. All the fluid milk we buy in the stores is Grade A; Grade B and C milks are processed into cheese and other dairy products.

Whole milk: By Federal law, whole milk must contain at least 3.25% milkfat and 8.25% milk solids by weight--which means it derives about 50% of its calories from fat. Because of this relatively high fat content, whole milk is best used only for infants and young children up to age 2, not older children or adults.

Reduced-fat milk (2%): This designation covers milk that contains 2% milkfat. The percentage of milkfat refers to the percentage of fat by weight, and much of milk's weight is water. Once you subtract the water from 2% milk, for example, you're left with a product that contains 20% fat by weight; such milk actually derives 35% of its calories from fat. Drinking 2% milk is a good way to wean yourself from whole milk at first, but is too high in fat as a permanent choice, unless your diet is otherwise very low in fat.

Low-fat milk (1%): One-percent milk gets 23% of its calories from fat. Many people find low-fat milk more appealing and a good compromise.

Skim milk/nonfat milk: This type of milk has as much fat as possible removed: It may not contain more than 0.5% milkfat by weight, and usually contains less than half a gram of fat per cup, deriving just 5% of its calories from fat. Skim milk has about half the calories of whole milk. It is the best choice for most adults, and is the only type of milk that should be consumed by people on strict low-fat diets. Unfortunately, skim milk has a very "thin" flavor and an unappealing bluish cast. There has been an effort in the dairy industry recently to address this issue. Individual dairies have added thickeners and/or additional milk solids to nonfat milk to give it the opacity and mouth-feel of higher-fat milks. At the moment, there is no official designation for this type of nonfat milk, so what the milk is called will vary with the dairy. Read labels to see what the dairy has added to the milk.

SPECIALTY MILKS
In addition to catering to the need for milk with varying fat contents, dairies supply specialty milk in response to particular health concerns and taste preferences. For instance, the widespread recognition of lactose intolerance among the American population has brought lactose-reduced milk to the dairy case; the growing awareness of osteoporosis prompted the development of calcium-fortified milk. Buttermilk, though not as popular a drink as it once was, is now a low-fat product that has many cooking uses.

Acidophilus milk: This type of milk (usually low-fat or skim) has the same nutritional value as the milk from which it is made. It differs from regular milk in that the bacterium Lactobacillus acidophilus has been added to it. (Unlike acidophilus yogurt, however, acidophilus milk is not fermented.) Some people believe that acidophilus milk is good for digestive upsets, or can help combat lactose intolerance. However, a study undertaken by the Mayo Clinic failed to find that acidophilus milk is useful in the treatment of irritable bowel syndrome; neither did this type of milk forestall the digestive problems caused by an inability to digest lactose.

Another benefit attributed to acidophilus milk is that it can help restore beneficial bacteria to the intestines after taking antibiotics (it's believed that L. acidophilus is normally present in the intestines). Live, beneficial bacteria are referred to generically as probiotics (as opposed, literally, to antibiotics); they are also present in yogurts that contain active cultures (be sure to read the label).

Buttermilk: Originally a by-product of buttermaking, buttermilk is now made by culturing milk--usually skim or low-fat--with a lactic-acid culture. Sometimes a small amount of butter is added for a smoother flavor and texture, but generally buttermilk gets just 20% of its calories from fat. A small amount of salt may also be added. However, buttermilk is not usually fortified with vitamins A and D.

Calcium-enriched milk: You can pack even more calcium into a glass of milk with this low-fat milk, which is fortified with 500 milligrams of added calcium per cup.

Lactose-reduced milk: The enzyme lactase is added to this product to help lactose-intolerant people digest it more easily. Its flavor is slightly sweet, but it has virtually the same nutrient values as regular 1% milk.

Low-sodium whole milk: Although salt is not added to milk, dairy products are naturally fairly high in sodium. Low-sodium milk has been treated to replace about 95% of its natural sodium with potassium. Its sodium content is about 6 milligrams per cup, compared with 120 mgs per cup in regular whole milk. The treatment almost doubles the milk's potassium content (from 370 to 617 milligrams per cup).

MILK IN OTHER FORMS
Canned, dried, or "boxed" milk: These products can stay ready on your pantry shelf for months, is obviously useful for those times when you suddenly run out of milk and it's inconvenient to go to the store. But some of these products have special qualities that make them unique cooking ingredients as well, so they needn't be used only as temporary replacements for fresh milk. For example, evaporated skim milk can be whipped for a rich, fat-free topping that has about one-tenth the calories of whipped heavy cream.

Dry milk powder: To make familiar nonfat dry milk (whole dry milk is mostly used in food manufacturing), the water is partially evaporated from fluid milk, then the milk is sprayed in a drying chamber to further dehydrate it. You reconstitute the resulting powder by adding water, usually in a proportion of about 1 cup of water to 3 tablespoons powdered milk. Instant nonfat dry milk, which consists of large, flakelike particles, dissolves quickly and smoothly.

Nonfat dry milk can also be used in recipes--or stirred into liquid milk--to add protein and calcium with minimal calories and no fat. A tablespoon of nonfat dry milk contains 94 milligrams of calcium, 27 calories, and no fat, and has added vitamin A and D.

Evaporated milk: This kitchen-cabinet standby is made by removing more than half of the water in milk and then canning and heat-sterilizing it. Since the cans can be stored at room temperature, this milk product is convenient to keep on hand for cooking and for emergencies. It is fortified with vitamin D and may also have added vitamin A. To use evaporated milk in place of fresh milk, reconstitute it with an equal amount of cold water (or use it undiluted in recipes that so specify). Undiluted, it is as thick as heavy cream, and can be substituted for cream in soups and sauces; if it is very well chilled, you can even whip it.

Sweetened condensed milk: This was one of the first canned foods to appear on the market. Created in 1856, condensed milk was a soldiers' staple during the Civil War. Like evaporated milk, it is made by removing about half the water content of liquid whole milk. However, a large amount of sugar is added to sweetened condensed milk, and so it is commonly used to make ice cream, puddings, and candies. Undiluted, it contains 982 calories per cup.

Ultra-high temperature (UHT) or ultrapasteurized milk: These dairy products are processed at temperatures higher than those used in regular pasteurization, thereby lengthening shelf life. In fact, UHT milk, packed in brick-style cartons (like juice boxes) that are presterilized and aseptically sealed, can be stored at room temperature for about six months. Once opened, however, it must be refrigerated.

Shopping

Milk products should always be marked with a "sell-by" date. Generally, the date is determined by the producer, although in some areas it may be regulated by a local authority. A common standard for setting an expiration date is eight to 12 days from the time the milk is pasteurized.

Since the lower part of a refrigerated display case is colder than the top, select a carton from the bottom of the display case if possible. Try not to buy more milk than you need; a larger size is no bargain if it spoils before you finish it. If you're not sure you will be able to use a full half gallon, opt for buying 2 quarts and leaving the second carton unopened until needed. Opening milk and exposing it to warm air activates bacteria, causing the milk to spoil more quickly, even if it is refrigerated.

Milk can also spoil if it hasn't been kept under constant refrigeration. To be sure that the milk you buy is perfectly fresh, sniff the top of the container for any sign of sourness; even cultured products like buttermilk should smell fresh, not bitter or sharp.

It's hard to find milk in glass bottles these days, but translucent plastic jugs are very common. Some studies suggest that milk in translucent plastic containers is more susceptible to significant losses of riboflavin and vitamin A from the effect of the fluorescent lights in supermarkets. Low-fat and skim milks are particularly sensitive to light. Cardboard containers, however, seem to protect against the light.

Storage

All milk should be promptly refrigerated, otherwise it will turn sour within a matter of hours. Dairy products last longer and taste better when kept cold--at 45°F or below. If the temperature of milk is allowed to reach 50°F, the shelf life is halved. (A 20-minute trip by car on a hot day can raise the temperature of milk by as much as 10°F.)

Milk containers should be sealed, closed, or covered, as milk readily picks up flavors and aromas from other foods. It's best to leave fresh milk in its original container, where it should keep for three to five days after purchase.

Canned evaporated or condensed milk can be stored at room temperature for six months. Once opened, it should be transferred to a clean, opaque container, covered tightly and refrigerated; the milk should keep for three to five days.

Aseptically packaged UHT milk has a shelf-life of about six months at room temperature. For best flavor, refrigerate it in the sealed package to thoroughly chill it before serving.

Unopened packages of nonfat dry milk should be stored in a cool, dry place. Reseal opened packages, as moisture will make powdered milk lumpy and eventually cause it to spoil. Discard nonfat dry milk if it smells scorched or rancid.

Preparation

Fluid milk is ready to use as it comes from the carton. When cooking with milk, be careful not to boil it, as this will cause a tough scum to form on the surface. Even when milk does not boil, it may scorch. For best results, heat milk over low heat and whisk or stir it frequently.

Cooking milk and other dairy products with acid ingredients, salty foods, and certain vegetables may cause the milk to curdle. To help prevent this, use gentle heat and avoid overcooking. Evaporated milk, because it has already been heated in processing, also makes curdling less likely.

On the other hand, sometimes you want milk to curdle: If a recipe calls for buttermilk or sour milk and there is none on hand, you can make a fine substitute by curdling regular milk with vinegar or lemon juice. For a cup of soured milk, place a tablespoonful of the acidic ingredient in a measuring cup, then fill to the 1 cup mark with milk. Stir, then let stand for five minutes.

Nonfat dry milk can be used both in its dry form and as a liquid. For its liquid form, follow the instructions on the package, but use 1/2 cup less water than specified for each one-quart envelope of dry milk; this will produce a richer-tasting milk with more concentrated nutrients. For best flavor and texture, mix the milk in a blender, and prepare it far enough in advance to allow for thorough chilling before you serve it.

You can also use nonfat dry milk in its powdered form to pack protein and calcium into meals you prepare. For instance, add a few spoonfuls of nonfat dry milk powder to soups, sauces, and gravies. The powder scorches easily, so cook it over low heat; a double boiler eliminates most of the risk of burning. Mix the dry milk into the ground turkey or lean ground beef that you use for burgers, meatloaf, or meatballs; add the powder to a shake made from skim milk or yogurt; or combine it with hot cereal before cooking.

Nutrition Chart

Skim Milk/1 cup

86
Total fat (g)
0.4
Saturated fat (g)
0.3
Monounsaturated fat (g)
0.1
Polyunsaturated fat (g)
0
Dietary fiber (g)
0
8
Carbohydrate (g)
12
Cholesterol (mg)
4
Sodium (mg)
126
Vitamin A (RE)
150
Vitamin D (mcg)
2.5
Riboflavin (mg)
0.3
Vitamin B12 (mcg)
0.9
Calcium (mg)
301
Phosphorus (mg)
248

Whole Milk/1 cup

150
Total fat (g)
8.2
Saturated fat (g)
5.1
Monounsaturated fat (g)
2.4
Polyunsaturated fat (g)
0.3
Dietary fiber (g)
0
8
Carbohydrate (g)
11
Cholesterol (mg)
33
Sodium (mg)
120
Vitamin A (RE)
76
Vitamin D (mcg)
2.4
Riboflavin (mg)
0.4
Vitamin B12 (mcg)
0.9
Calcium (mg)
290
Phosphorus (mg)
228

Nonfat Dry Milk/1/3 cup

82
Total fat (g)
0.2
Saturated fat (g)
0.1
Monounsaturated fat (g)
0.1
Polyunsaturated fat (g)
0
Dietary fiber (g)
0
8
Carbohydrate (g)
12
Cholesterol (mg)
4
Sodium (mg)
121
Vitamin A (RE)
150
Vitamin D (mcg)
2.5
Riboflavin (mg)
0.4
Vitamin B12 (mcg)
0.9
Calcium (mg)
284
Phosphorus (mg)
219

Buttermilk/1 cup

99
Total fat (g)
2.2
Saturated fat (g)
1.3
Monounsaturated fat (g)
0.6
Polyunsaturated fat (g)
0.1
Dietary fiber (g)
0
8
Carbohydrate (g)
12
Cholesterol (mg)
9
Sodium (mg)
257
Riboflavin (mg)
0.4
Calcium (mg)
284
Phosphorus (mg)
219


Date Published: 04/20/2005
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