hen it comes to what we are willing to eat, most people are slaves to the numbers in one way or another.
There are calories to be counted, and fat grams; when that palls, you can move on up to more advanced math, like calculating a food's percentage of calories from fat or graphing the space-time continuum of somehow choking down the recommended four to five servings of vegetables a day -- plus the eight to 10 glasses of water we're all supposed to drink -- while carrying on a normal life.
The most reassuring number you're likely to find on your packaged food, though, is the date. Sometimes called the expiration date, sometimes the sell-by, freshness, quality or pull date, it's the number most people assume will tell them whether food is safe to eat. Most people intuitively look for the latest dates on milk, cheese and meat they can find; once they're back home, the rule is generally "use it or lose it" before the date passes.
All of which is perfectly reasonable, food experts say, and anyone who's had a run-in with a disregarded expiration date's likely to agree. There's nothing like pouring a chunk of skim milk onto the morning's Wheaties to make a person learn to check for freshness.
Quality, not safety
That date stamped on the milk carton, though, might not mean what you think it does. In fact, with only a few exceptions, no laws regulate package dates, which are voluntarily stamped on the package by the supermarket or food producer. The federal government requires expiration dates only on certain baby foods and all infant formula, and it is illegal to sell those items after the date of expiration.
Otherwise, it's a dating game.
"It's a quality date, not a food safety date," says Jeffrey Lineberry of the retail food safety section of the state Department of Health and Human Services. "Manufacturers tend to be really conservative when they assign sell-by dates because they don't want the consumer to eat something that tastes bad or isn't at its optimum freshness.
"But the government isn't worried about the freshness quotient; we're just concerned about public health and food safety," he says.
Because infant formula is considered a baby's full diet, the law requires stores to pull formula off the shelves when its expiration date is up, as the nutrients in foods tend to deteriorate over time.
State law does require that dates be stamped on certain dairy products like milk and yogurt, but stores don't have to pull milk off the shelf if it's reached the expiration date.
Even though the law requires that a date be stamped on every milk carton, it's still up to each dairy to choose its own date. Because some plants are older than others, because storage and temperature and the qualities within each lot of milk itself can differ, one milk producer might opt for an earlier use-by date than a competitor, even if the milk was processed at exactly the same time.
A Safeway spokesperson said the store usually gives its milk a freshness date of 14 days past processing; most food experts agree that milk can be used up to seven days after the stamped freshness date.
The Department of Health and Human Services' food safety Web site says date codes and other codes such as "batch" and "lot" codes that identify when a product was made are also recommended for the producers' convenience, because they help retailers trace and rotate inventories properly, and if a food is recalled, batch numbers make it easier for the product to be removed from sale.
The meat of the matter
While state laws make it illegal to sell spoiled food, there's no law that keeps a supermarket from repackaging foods that haven t sold, and relabeling them with a later freshness date. In fact, last year it was just such practices that led state Sen. Tom Hayden (D-Los Angeles) to introduce a bill that would establish rules for assigning freshness dates to meat products, require a standard date-coding system and prevent grocers from using marinades or sauces to mask meat discoloration.
The grocery lobby rallied against the bill, which died in part because the grocery lobby is pretty powerful, but also because the issue of food dating is pretty complex.
"We could make regulations establishing a freshness date, but who determines what that date is? For every product? The implications for the consumer are completely unknown," says Mr. Lineberry, who adds that food producers' self-interest tends to keep them assigning conservative freshness dates, rather than run the embarrassing risk of having a consumer buy a carton of, say, fuzzy cottage cheese with a current freshness date.
The problem isn't just that there's a huge range of packaged foods, all of which would require different expiration dates. It's also that storage and shipment methods affect the shelf life of packaged foods, and because foods are usually shipped to regional distribution centers before they make it to the supermarket, and it's hard to guarantee uniform freshness when conditions vary so widely. At any point during the long journey a food makes from the manufacturer to the market, foods can be exposed to temperature extremes or jostling that affects the air-tightness of packaging, and therefore the freshness of its contents.
Running the numbers
So if the freshness date is just a guideline for the convenience of consumers and retailers both, how can you make sure the food you're buying is as fresh as possible?
Basically, consumers are advised to talk to their grocers, know the policies at the stores they frequent, and vote with their feet. If there's an inch of dust on the milk, the freshness date is past, or refrigeration seems to be a formality, maybe it's time to shop at a kinder, cleaner market.
While stores that sell food that's gone bad before its expiration date don't have to issue a refund or swap, many do replace the product in the interest of keeping their customers happy. Knowing the policies of your favorite grocer's deli counter might help you sleep better at night -- and a chat with the managers might just get you some tips on some new way to cook that tri-tip whose freshness date you've been inspecting.
How long will it keep?
Once you've taken it home from the grocery store and refrigerated it properly, how long after the date can you hope to use your food? Generally -- except for fresh beef and pork, which should not be kept for more than three to five days, and poultry, seafood and hamburger, which should be used within two days -- most foods can be kept for seven days after purchase, even if that time period takes you past the date.
Look for spoilage anyway. Sniff. Examine. And if there's any doubt, toss it. Wasting a little money is always better than risking illness.
SALLY, THIS CAN BE AN INFORMATION BOX.
Storage advice
The U.S. Department of Agriculture and International Food Information Council recommend the following guidelines for keeping and storing meat and dairy products.
Meat
Roasts, steaks, etc.: 3-5 days (wrapped loosely)
Hamburger: 1-2 days (wrapped loosely)
Lunch meats: 7 days in package after sell-by date; 3-5 days if opened and wrapped tightly
Dairy
Milk: 5-7 days after the sell-by date
Cottage cheese, sour cream: 3 days (covered)
Eggs: 3-5 weeks if purchased before the date on the carton
Hard cheese: 4-12 months, wrapped tightly
