What’s in a Date?

David Golden is a Herbert College of Agriculture professor of food microbiology.

David Golden is a Herbert College of Agriculture professor of food microbiology.

One recent study showed that about 90 percent of Americans do not understand the meaning of date labeling on food. You may be surprised to know that, aside from infant formula, date labeling is completely optional. There is no regulatory requirement to place date labeling on food packages. So why do manufacturers do it?

Date labeling has nothing to do with the safety of the food. The manufacturer provides “best by” and “use by” dates to tell you that, if you consume the food by that date, it will be at its freshest quality and flavor. “Sell by” date is for retailers as a recommendation to remove the product from their shelves once the day is reached. But none of these is absolute. Some foods may remain fresh well after the date label. For most foods, it is perfectly acceptable and safe to consume foods well after the date is reached.

As a general rule, I recommend that you don’t purchase foods that have reached the “sell by” date and dispose of highly perishable foods when the “best by” or “use by” date is reached. Highly perishable foods are those that are unprocessed or minimally processed and require refrigeration. Most condiments, salad dressings, dry snack foods and even some refrigerated foods, like yogurt and most cheeses, will not support the growth of pathogenic bacteria (i.e., those that make you sick). The only organisms that will grow in most of these shelf-stable products are spoilage organisms, and that would be only after they have been opened. And not all spoilage is caused by microorganisms; some go stale or become rancid.

So, how do you know when to toss a food item? Bulging of cans or other food containers is an indication that something is growing in the food. Similarly, if you open a ketchup container and it pops like a champagne bottle, something is growing in it. If mold is growing on cheese or bread, they are obviously spoiled. Spoiled potato chips may lose their crispness or taste rancid.

The bottom line is this: If it smells bad, tastes bad or looks strange, don’t eat it.

While well-intended, “use by” and “best by” dates have a downside. The majority of the 90 percent of Americans who don’t understand it throw away food once it reaches the date labeled. Over 100 billion pounds of food is wasted in the United States every year, accounting for about 40 percent of all of our food. Households account for about 40 billion pounds of food waste, with about 20 percent tossed out because the “use by” or “best by” date has been reached.

When you toss perfectly good food, you are literally throwing money into the trash, not to mention clogging up landfills. But, if you really won’t eat that yogurt when the “best by” date is reached, just send it to me. I’ll take care of it for you.