Starting this week, customers will know a lot more about where their meat and poultry came from and whether the fruit they buy was grown in Costa Rico, Jamaica or the U.S.

A law, years in the making, now requires disclosure of the origin of many foods, including meats, fresh fruits and vegetables and certain nuts.

Recent scares, including salmonella-tainted peppers from Mexico and China's milk scandal have raised consumers' awareness.

"A lot of countries are having problems with their meat and produce.  We should know where our food's coming from," said customer Judd Pollock.

Opponents argue the law will cost wholesalers and retailers billions of dollars and raise food prices and unfairly imply that imported food is not safe.

"We're not opposed to other countries bringing their product in.  We're just saying join us, put your name on it," said Tom Buis, President, National Farmers Union.

Some stores, such as Whole Foods, already label and even trace some products back to the farm where they were produced.

"The good thing is the consumer's going to know where their product is coming from," said Dale Moore of Whole Foods.

And for many customers that provides a level of confidence they welcome.

Retailers have six months to add the country of origin labels to help ensure that consumers know exactly where their food is coming from.

Small food outlets like butcher shops, restaurants and school cafeterias are exempt from the new law, and it does not apply to processed foods.

Here are some common questions as shoppers navigate the change:

Q: What does the new law require?

A: That retailers notify customers of the country of origin -- including the U.S. -- of raw beef, veal, lamb, pork, chicken, goat, wild and farm-raised fish and shellfish, fresh or frozen fruits and vegetables, peanuts, pecans, macadamia nuts and whole ginseng. (The aim was big agricultural commodities; ginseng was added for fear of imports masquerading as U.S.-grown.)

Q: Where will I see the country of origin?

A: Anywhere it fits. The rubber band around asparagus; the plastic wrap on ground beef; the little sticker that says "Gala" on an apple. If a food isn't normally sold in any packaging -- such as a bin of fresh green beans or mushrooms -- then the store must post a sign.

Q: Aren't many foods already labeled?

A: Some fresh produce already uses origin labeling as advertising. "Fresh from Florida" or "Jersey Grown" or "Vidalia Onion" tags don't have to be changed under the new rules; the shopper should realize they're all U.S. products.

The COOL law mandating such labels first passed in 2002, but lobbying by grocery stores and large meatpackers led Congress to delay the U.S. Department of Agriculture from implementing it. Seafood labeling was phased in first, in 2005 -- a key change given recurring safety problems with fish and shellfish from certain countries, including China.

Q: What's the biggest exception?

A: The labels aren't for processed foods, meaning no label if the food is cooked, or an ingredient in a bigger dish or otherwise substantially changed. So plain raw chicken must be labeled but not breaded chicken tenders. Raw pork chops are labeled, but not ham or bacon. Fresh or frozen peas get labeled, but not canned peas. Raw shelled pecans, but not a trail mix.

Q: What if the foods are merely mixed together?

A: They're exempt, too. So cantaloupe slices from Guatemala get labeled. Mix in some Florida watermelon chunks, and no label. Frozen peas, labeled. Frozen peas and carrots, no label. As for bagged salads, USDA considers iceberg and Romaine to be just lettuce, so that bag gets a label. Add some radicchio? No label.

Q: Must all stores comply?

A: No. Meat and seafood sold in butcher shops and fish markets are exempt.

Q: What if companies buy food from various places -- beef from both U.S. and Mexican ranchers, for instance?

A: That's a bone of contention between large U.S. meat producers and smaller ranchers that produce exclusively U.S. animals. Tyson Fresh Meats, for instance, says it's too expensive to separate which of its cattle came from which country. So in a July letter to customers, Tyson said it would label all beef "Product of the U.S., Canada or Mexico." The National Farmers Union is protesting; USDA is considering the complaints.

Q: Aren't country labels on some processed foods?

A: Yes, tariff regulations have long required that a food put into consumer-ready packaging abroad be labeled as an import; that doesn't apply to bulk ingredients.

Q: When does the change take effect?

A: The law goes into effect Tuesday, although USDA won't begin fining laggards until spring. Violations can bring a $1,000 penalty.