10 Things to Know About Yogurt

1. What those bacteria do
Lactobacillus bulgaricus and Streptococcus thermophilus, the two bacteria required by FDA standards for yogurt, are added to a warm milk bath, where they proceed to ferment and coagulate into a semisolid, producing tangy lactic acid along the way. Manufacturers can add other probiotics, like Lactobacillus acidophilus and Bifidobacterium, but they're not required or regulated.

2. Love the whey.
The clear liquid that often separates and floats to the top of many yogurts contains a little protein and tart flavor: Don't pour off—stir in.

3. Look for the seal.
Established by the National Yogurt Association, the seal (shown here) indicates that the manufacturer is promising that the yogurt contains at least 100 million active starter cultures per gram when manufactured. It's not FDA-policed, though.

4. Get all the active cultures you're paying for.
Some yogurts are heat-treated after fermentation, which neutralizes the good-for-you bacteria required for production, meaning that the potential health benefits are neutralized, too. Check the packaging: The FDA mandates that these yogurts be labeled "heat-treated after culturing." If your yogurt is not heat-treated, the package may say "active yogurt cultures," "living yogurt cultures," or "contains active cultures."

5. You can strain your own Greek-style yogurt.
Draining off some of the whey yields the thick yogurt that has made Greek-style hot. Even the nonfat variety has a rich, satisfying texture. Greek yogurt is expensive, though, because it requires more milk. You can produce it for about $1.50 per cup yourself. Start with a plain, natural yogurt, nonfat or low-fat.

Step 1: Spoon plain nonfat or low-fat yogurt into a fine-mesh steel strainer lined with a paper tower or coffee filter.

Step 2: Set the strainer into a bowl, cover with plastic wrap, put in the fridge, and let the whey drain out of the yogurt overnight.

6. OK for the mildly lactose-intolerant
People with mild lactose intolerance usually tolerate yogurt because the live active cultures break down much of the lactose into glucose and galactose—simple sugars that are easier to digest.

7. Frozen "yogurt" vs. frozen yogurt
Frozen yogurt is not regulated by the FDA, meaning the scoop in your cone could be made entirely from yogurt—or could be ice cream with a little yogurt stirred in. The Live & Active Cultures seal signals the manufacturer's assurance that it is, actually, yogurt.

8. Watch the fat content in some of the fancy yogurts.
Yogurt is one of those health-halo foods, but not if it's full-fat. Check out Liberté's ultrarich, full-fat Méditerranée line: More than a third of the calories (and there are 250 of them) come from the 10 grams of saturated fat in a 6-ounce container. Fage Total Greek has 18 grams in 8 ounces. Fortunately, these same companies make delicious low- and nonfat yogurts.

9. Also watch out for added sugar.
Scan the ingredient list for added sugars like high-fructose corn syrup, sucrose, dextrose, maltose, maple syrup, or fruit juice concentrate. Six ounces of typical plain nonfat yogurt have about 11 grams of natural sugar and 80 calories; flavored varieties can add as much as 14 extra grams of sugar and 50 or so calories.

10. Make easy yogurt dipping sauces

Indian-style basic raita: combine 1½ cups plain low-fat yogurt, ¾ cup chopped seeded peeled cucumber, ¾ cup chopped seeded tomato, ¼ teaspoon salt, and 1 teaspoon garam masala. Cover and chill before serving.

Greek-style basic tzatziki: combine 1 cup plain low-fat Greek-style yogurt, ¾ cup finely chopped seeded cucumber, 1 tablespoon chopped mint, 1/8 teaspoon salt, and 1/8 teaspoon white pepper. Cover, chill, serve.