Like many Americans, Michelle Liss of Eden Prairie pays close attention to the “sell by,” “use by” and “best before” labels on the packaged and perishable foods in her kitchen.

“I get a little freaked out when an item is past the use by date,” she said. “I discard it when it isn’t fresh.”

Most people do the same thing, even though much of it is still perfectly good to consume. In fact, Americans have grown to rely so much on the food dating game since it was implemented in the 1970s that we now throw away 20 percent of our food, over 160 billion pounds of it per year, according to the U.S. Department of Agriculture.

It isn’t surprising that consumers take extra precautions when they hear regularly about salmonella, E. coli or other foodborne illnesses. But what started as a consumer demand that food be verifiably fresh has evolved into a confusing mishmash of laws that are different in each state. Only infant formula is regulated by the federal government.

The inconsistency is causing discarded food to be the largest single contributor to the nation’s landfills and costing Americans money, according to a recent study by the Natural Resources Defense Council (NRDC) and the Harvard Food Law and Policy Clinic. The average family of four that spends about $632 to $1,252 per month on groceries is throwing away about $112 to $190 each month on outdated food and restaurant leftovers, researchers concluded.

Obscene amounts of food are being wasted, consumer advocates argue, because of a misconception that eating food past its “use by” date is about safety, when it’s really about freshness.

Consumers are discarding items a day or two past their freshness date because they think the items are potentially harmful when they’re not, said Sarah Klein, an attorney at the Center for Science in the Public Interest.

“It may not taste as good as it did the day before,” she said. “But it’s perfectly safe to eat. There’s no need to throw it away.”

The time to get rid of food is when it looks, smells or tastes bad, Klein said. In general, eat or freeze meat by its freshness date, and throw out fresh seafood when in doubt.

Minnesota has a requirement that foods with less than a 90-day shelf life must be date labeled. Products with a longer shelf life such as cereal are not required to be labeled if they are sold in Minnesota, but they almost always are because manufacturers want to be able to sell their products in states with stricter requirements, said Ted LaBuza, professor of Food Science and Engineering at the University of Minnesota.

“Manufacturers put dates on nearly all of their food products because consumers want them,” he said.

But experts say that manufacturers deserve some blame for excess waste, too. Many consumers and some at the NRDC think that manufacturers are shortening the date span on their products to get consumers to buy more often, LaBuza said.

“There’s no state law telling manufacturers how to determine the freshness date, so they’re free to choose the dates they want,” he said. Nearly 70 percent of companies just follow what their competitors are doing, LaBuza said.

But shortening the “sell by” date range can also mean that supermarkets and wholesalers get stuck with food at its freshness date because safety- or freshness-conscious consumers won’t buy it. Many consumers reach to the back of a display for an item with the newest date and avoid others.

A home for old food

What happens to the older items? When they don’t sell, a retailer risks its reputation for freshness by not removing them. A supermarket can throw it out, but that’s often the most expensive choice with rising trash removal costs.

Some is returned to distributors and sold to food outlet stores. Mike’s Discount Foods in Anoka, Fridley and Hilltop, So Low in Minneapolis, and DealSmart in Little Canada and Mounds View sell the items near or past their freshness dates at 30 to 70 percent off retail.

Mike Abernathy, owner of Mike’s Discount Foods, buys food that’s near its freshness date as well as surplus food. Currently, he’s selling chicken broth with a July 2013 freshness date at three for $1. “We keep dropping the price until it sells,” he said.

Because many consumers assume that food past its freshness date is unsafe, they think selling it is illegal, which it isn’t. “The food is safe as long it’s been handled properly. The only thing you can’t sell past its freshness date is infant formula,” he said.

Canned food, for example, is generally safe for up to three years after its freshness date, according to the USDA, but Abernathy takes any canned goods off the shelf once they’re a year past their date.

Much of the unsold food near its freshness date goes to local food shelves, said Bob Chatmas, chief operations officer at Second Harvest Heartland food bank in St. Paul. Second Harvest collects perishable food from Cub, Rainbow, Target, Wal-Mart, Sam’s Club, Lunds/Byerly’s and Quiktrip. In 2008 the food bank collected 5 million pounds, but it’s on track to collect 30 million pounds this year.

When accepting donations, Second Harvest uses guidelines from the USDA and the Food Marketing Institute. “Our highest priority is food safety,” said Chatmas, whose organization will serve almost 600,000 people this year in 59 counties in Minnesota and Wisconsin.

Safe handling

That means proper storage. It’s the key to product freshness and safety, LaBuza said. Refrigerator thermostats should be set at about 40 degrees or lower. “If you keep the thermostat at 34 to 36 degrees, you can get twice the storage life than if it’s kept at 50 degrees,” said LaBuza.

Besides a fridge at 40 degrees, experts also recommend keeping stored food away from a heat source such as an oven or a fridge. For a comprehensive guide to length of time for food storage, search for “The Food Keeper: A Consumer Guide to Food Quality and Safe Handling” online, put out by the Food Marketing Institute and Cornell University.

No effort is underway to demystify the current food labeling system, but the NRDC recommends standard labeling language that distinguishes between safety and quality-based dates, increasing the number of “freeze by” dates when possible, and putting the date labels in a predictable, consistent location on the packages.

That would be a helpful step for consumers, Liss said. “Right now it’s so confusing that I wonder if the dates are there just because food companies want us to throw it away and buy more,” she said. “Standardization would be a nice thing.”