Low-acid canned goods keep their quality longer than high-acid ones.

Low-acid canned goods keep their quality longer than high-acid ones. Credit: AP

How do you decipher date codes on canned food and, if you manage to decipher them, how long after the date is it safe to eat the food?

This question was a follow-up to my recent column on the difference between the "sell by" and "use by" dates that are found on packaged food. Both are examples of what the industry calls "open dating," easily interpreted information found on such perishable products as meat, eggs and dairy.

In contrast, manufacturers of canned and boxed foods -- which have much longer shelf lives -- often use "closed dating" or "coded dating," which must be deciphered to be understood.

According to the Canned Food Alliance, "the codes vary from manufacturer to manufacturer and usually include coding for time and place of canning. Most manufacturers offer a toll-free number to call for questions about canned food expiration dates."

They would have to; the codes are difficult to crack. Numbers 1 to 9 can represent the months of the year, from January to September, with October, November and December represented by "O," "N," and "D." Or not. Days of the year may correspond to their Julian calendar dates, that is, where they fall from 1 (Jan. 1) to 365 (Dec. 31). The Julian date for Oct. 10 is 283.

You'd think that manufacturers' websites would be of some use here, but those of Del Monte, Progresso and Dole were not. At kraftfoods.com, however, the FAQ section gave code-breaking tips for many products, including Kraft Macaroni & Cheese, for example:

MAR 07 99 best when used by date

S-1 16:03 S = plant code (Springfield), 1 = production line, 16:03 = time of packaging

As for how long canned food is safe, according to the USDA Food Safety and Inspection Service, high-acid foods such as tomatoes and fruit will keep their best quality up to 18 months after purchase; low-acid foods such as meat and vegetables, for two to five years. "Best quality" here refers to color and texture. The food safety service says, "if cans are in good condition (no dents, swelling or rust) and have been stored in a cool, clean, dry place they are safe indefinitely."

Addio, Marcella

On Sept. 29, Marcella Hazan died at her home in Florida. The Italian-born cookbook author, 89, was my culinary idol. To say that her masterwork, "Essentials of Classic Italian Cookbook," was my favorite cookbook doesn't begin to express its influence on my life and work. Her approach to cooking -- equal parts simplicity and rigor -- has become my own.

Among her sage words of advice:

"Do not serve pasta with a pool of sauce resting on top, no matter how pretty it may look. It is only with thorough tossing that you achieve a satisfactory fusion of pasta and sauce. No other step is more important."

"When I think of all the people I know who will cook anything as long as they don't have to fry it, I think, sadly, of what they are missing."

"The unbalanced use of garlic is the single greatest cause of failure in would-be Italian cooking."

And, of course, the immortal "Wet things don't brown."

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