We’ve all done it: Taken the milk out of the fridge, noticed the “sell-by” date has passed, and given it a sniff to see if it’s still good. The question is: Are you putting yourself at risk by consuming milk and other foods that have passed their “expiration” date?

The answer, health experts say, is often no — depending on how much time has passed since that date and what type of food you’re eating.

In fact, Consumer Reports estimates that for every dollar Americans spend on food, about 10 cents’ worth is unnecessarily tossed into the trash. That adds up to about $1,500 of wasted food per year for an average family of four, according to the U.S. Department of Agriculture.

The primary reason: Misconceptions about what date labels on food packages — “sell by,” “use by,” “best by,” and the like.

“Most consumers don’t realize that they’re really more about food quality than food safety,” says Robert Gravani, a professor of food science at Cornell University, in the current issue of the magazine.

While food may not be at its best after those dates — in terms of freshness or taste — most can be safely consumed days or even weeks after the label suggests it is past its "expiration” date. And the sniff test is often an acceptable way to determine if an “expired food” is still good.

“Foodborne illness comes from contamination, not from the natural process of decay,” says Dana Gunders, a staff scientist at the Natural Resources Defense Council and the author of “Waste-Free Kitchen Handbook.” “And our senses are well-equipped to recognize decay.”

Foods that spoil, become rancid, or moldy are likely to look, smell, and taste bad before they actually become unsafe to eat, experts note.

Federal laws don’t require foods to carry a date label except for infant formula, and even that stipulation is based on nutritional quality, not safety. Several states have labeling regulations, but the guidelines vary.

To help guide consumers, USDA offers the following general labeling definitions:

• Sell-by: This is the date by which food manufacturers recommend retailers remove products from store shelves. You shouldn't buy anything from a store after this day (also known as the "expiration date"). But a food in your fridge or pantry that is so dated is, in all likelihood, still edible days or even weeks afterward (depending on what it is).
• Use by: This is the last day that a food manufacturer will guarantee a product's quality and freshness, but it does not mean the food is unsafe or should be discarded after this date.
• Best if used by: The flavor or quality of a food product may not be as good after this day. But it may still be OK to eat.

Manufacturers typically decide on dates and terms based on their own product testing, according to Consumer Reports. But they tend to be conservative.

Ethel Tiersky, a food-safety specialist who runs the nonprofit ShelfLifeAdvice.com Website, has compiled information on hundreds of foods that are safe after expiration dates, based on university studies, government experts, and other reliable food-safety sources.

She tells Newsmax Health that all food products will spoil eventually, of course, but in most cases labels aren't a good indication of when. Here’s a summary of Shelf Life’s findings:

Milk, properly refrigerated, is still good about a week after its "sell-by" date.

Cottage cheese lasts for 10-14 days after the date on the packaging.

Yogurt can be safely eaten up to 10 days after its "sell-by" date; beyond then the live bacterial cultures (which are healthful ingredients) will start to die.

Mayonnaise is still good for a month after its expiration date (unopened) and up to four months after opening. 

Eggs, refrigerated, should last at least three to five weeks after the "sell-by" date.

Canned goods are good to eat long after labeling dates, as long as the can is in good shape. If a can is dented, rusted, or swollen, toss it out.

Many other products — cheese, condiments, butter, margarine, fruit juices — can all be consumed long after the labeling dates suggest. Experts recommend consumers apply some common-sense judgments, when deciding whether to keep or toss a food:

• Check for spoilage. Mold or discolored appearance can bacterial contamination.
• Is it appetizing? If the product smells or looks bad, don't eat it.
• Assessing pantry foods. Shelf-stable goods that contain no moisture or fat last long past the "use-by," so trust your senses of smell and taste to guide your decisions.
• Combating food-borne illnesses. Most cases of food poisoning are due to improper hand-washing, keeping food at the wrong temperature, insufficient washing of foods, cross-contamination (bringing a food that is served raw in contact with contaminated meats and other items).