Decoding Expiration, Use-By, Best-By, and Sell-By Dates

Expiration dating is not federally required on all products

Woman looking at milk carton
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When purchasing packaged foods, most of us look for some type of expiration date, sell-by date, or use-by date imprinted on the container to determine the freshness. What those dates mean, however, is confusing, and once the item is in your fridge or pantry and has reached that date, you may wonder whether you need to toss the product or if it is still safe to eat.

You may be surprised to learn that dating is not required by US federal law, with the exception of infant formula and baby foods, which must be withdrawn from the market by their expiration date. Freshness dating and the terms used is voluntary on the part of manufacturers, except for dairy foods and meat in some states.

To add to this challenge, stores are not legally required to remove outdated products from their shelves, and although most markets are vigilant about rotating stock, some are not. In a properly stocked store, the freshest items will be at the back of the shelf or underneath older items; this helps the store move older merchandise. Thus, in order to ensure you are getting the freshest product, it is necessary to scrutinize packaging and choose the longest outdates. But first, you need to understand what each date distinction means.

Best if Used By/Before Date

Out of all of the date terminology, the USDA Food Safety Inspection Service prefers this wording as they think it is the easiest for consumers to understand. With an emphasis on the best qualifier in this term, it means the product should retain maximum freshness, flavor, and texture if used by this date. It is not a purchase-by or safety date. Beyond this date, the product begins to deteriorate, although it may still be edible. The Grocery Manufacturers Association and the Food Marketing Institute also favor these terms rather than "expires on" or "sell by."

"Use by" date has a similar meaning to "best if used by." It means the product will have the best qualities if consumed by the date noted. The USDA prefers manufacturers to add "best" to this phrase.

Expiration Date

This phrasing is often present on packaging for meats and some dairy as some states require an expiration date on meat or milk. It's best not to use the product past this listed date in those cases as it signifies when the food most likely will spoil. For other food items, the manufacturer may have simply chosen to use "expires by" instead of "best if used by" to warn that the product may be stale or have lost its flavor by that date. Check all food carefully for signs of spoilage.

Sell-By or Pull-By Date

The "sell-by" date is geared toward the supermarket versus the home kitchen. This distinction is used by manufacturers to tell grocers when to remove their product from the shelves, but there is generally still some leeway for home usage. For example, milk often has a sell-by date, but the milk will usually still be good for at least a week beyond that date if properly refrigerated.

Guaranteed Fresh Date

You will most often find this phrase on perishable baked goods, meaning that beyond this date, freshness is no longer guaranteed. However, the product may still be edible.

Pack Date

Mostly used on canned and boxed goods, this date refers to when the item was packed. It is usually in the form of an encrypted code not easy to decipher. It may be coded by month (M), day (D), and year (Y), such as YYMMDD or MMDDYY. Or it may be coded using Julian (JJJ) numbers, where January 1 would be 001 and December 31 would be 365. In even more convoluted coding, letters A through M (omitting the letter I) are often assigned to the months, with A being January and M being December; the letter is in combination with a numeric day, either preceded or followed by the numeric year.

Checking Dates When Buying Food

Whether "best by," "sell by," or "expires," all of these dates are placed on food packaging to ensure good food safety. In addition to reading these dates, following a few tips will help you get the most out of the food you purchase.

When buying foods, always check the expiration date. Select the date farthest in the future for optimum shelf-life. One type of product to carefully scrutinize is a baking mix; many contain dehydrated fats which can become rancid with time or leaveners that may lose their potency. Make sure you check the date.

Keep in mind that fresher packages may be at the rear of the shelf or buried behind other products. Depending on how quickly you will be using an item, it may be worth digging out the newer product, but be sure to re-stack for the grocer.

Regardless of the expiration date, do not take a chance on cans that are bulging or oozing from the seam. Dented cans should also be avoided.

Storing Food After Purchase

To ensure your food retains its best quality for the longest period of time, there are a few simple steps to follow when grocery shopping. For one, get your food home quickly from the store and into proper storage; if you are running errands, make the supermarket your last stop.

Once home, take a tip from grocers and rotate your stock in your pantry and fridge. Rather than trying to decipher cryptic codes on cans, use a marker to write the purchase date on packaged foods to help you judge their age. Also examine cellophane, plastic, and box packages to be sure they are not punctured or torn. Once the seal is penetrated, the integrity of the contents is compromised.

Optimum storage temperature for canned goods is 65 F; higher storage temperatures can reduce shelf-life by up to 50 percent. Some canned goods (such as condiments and pickled items) will still retain some longevity if refrigerated. Most condiments will have a warning to refrigerate after opening if necessary, so check the packaging carefully.

Most canned goods can be stored up to one year at an optimum temperature. Citrus fruits, fruit juices, pickles, peppers, sauerkraut, green beans, asparagus, beets, and all tomato products should be used within six months. If summer heat brings your kitchen temperature to 75 F. or above, even for a short time period, cut those storage times in half.

In general, foods canned in glass have a longer shelf-life. However, they must be stored in the dark since light can accelerate some natural chemical reactions. Canned foods should never be frozen in the can or jar; the expansion can split the seams of the can or break the glass container. 

Once opened, many of the dates become obsolete since the contents now become perishable. Therefore, it is advisable to use products as quickly as possible after opening. Be sure to refrigerate leftovers in a covered container (and not the can it came in) and use within three to five days.

Your best defense is to trust your eyes and nose. If it looks bad or smells bad, toss it out.