Thursday, October 17, 2019

"Best By" Dates--What Those Numbers Stamped on Cans and Packages Really Mean

You know, those various dates stamped on packages have been a business boon for food manufacturers. Because most Americans don't understand those numbers, hundreds of thousands of pounds of food get thrown away every day. So much money is wasted. Then there are those of us who do use foods way past the magical date on the package, much to the horror of those around us. Having a little understanding of these dates and how they work can make us and our family feel a little more reassured.
To begin with, let's take a look at the various terms.
  • Best by dates are used by the canned food industry. They are not expiration dates. The manufacturer states that the product will remain at peak quality and nutrition through that date. It has nothing to do with safety.
  • Use by is the last day peak quality is guaranteed by the manufacturer. 
  • Sell by dates are for perishables like dairy and produce. It is the last day for which the item is at peak quality and freshness. The issue is the quality of the item--taste, freshness, consistency--not whether it is about to spoil. 
  • Guaranteed fresh usually refers to bakery items. The bread doesn't magically go bad the day after; it just may not taste quite so fresh.
Noteworthy is the fact that none of these dates are required by the government. The only food that must be dated is baby formula. All those other dates--best by, use by, sell by, guaranteed fresh--are provided voluntarily by the food manufacturers. It helps grocery stores rotate stock efficiently. The fact that most consumers don't understand the meaning of those dates and interpret them to mean discard is an added bonus.

You may have noticed that there are frequently some other numbers and letters on those packages, usually right before or right after the use by or best by dates. The look like a secret code--and they are! Because the government doesn't require these dates (and I'm not saying the government should), there is no standardization. Companies are free to label however they want. But it can lead to confusion and certainly makes for some difficulty in decoding. All of these codes are the pack dates, and they're most often used for canned goods. Some examples of common ones are listed below. But remember, companies are free to do whatever they want, or nothing at all.
  • MMDDYY--month, day, year. You got this one.
  • Number 1 through 365, for whatever day of the year it was canned. Also pretty easy. 
  • A mixed code where numbers 1 through 9 are used to represent January through September, and the letters O, N, and D are for October, November, and December, and then numbers are used for the day of the month and the year. 
  • A four-digit number code where the first number is for the year (i.e., 2019 is represented by a 9), and the next three digits are the day of the year (i.e., 145 would stand for the 145th day of the year, May 25). (Yeah, this only works if you keep food less than 10 years.) 
  • A six-digit code like the following S03069. The S is a plant code and had nothing to do with the date. March is represented by 03. The sixth day of the month is 06. The 9 is for the year, meaning this can was packed March 6, 2019.
So why are these dates important? Well, they can help you understand how long your food may really last. In general, acidic foods like fruits will not last as long as vegetables or meats or milk. Tomatoes and pineapple seem to have the shortest shelf life. They are so acidic that the acids eat through the coating on the interior of the can and then the can itself, making a complete mess of things when they leak. (Pineapple and tomatoes canned in glass last much longer.)

Vegetables may be good up to five years, meats up to ten years. Milk can go quite a while, too, but it may turn brown and look unappealing.

Rather than the date stamped on the can, of far greater importance is to focus on the condition of the can itself and how it was stored. Is the can bulging or rusted or dented? That bulging can gets tossed, no questions asked. If the can is dented, the seal may have been compromised, and it will be difficult to determine just by looking at it. Is it a significant dent (which is more likely to be a problem)?  Or just pushed in a little bit?  If the can is rusted, maybe it's just the beginning of rust and the rust hasn't eaten all the way through the can yet. The rule is that if the seal is intact, the food is safe regardless of age. But with dented or slightly rusted cans, it can be difficult to tell. So there is a simple test to perform when determining whether the contents are safe.

First, clean the lid well. Then put a little bit of water on top and tilt the can so that the water pools against the rim. Pierce the rim with your can opener through the little pool of water. If the water is sucked into the can, the food is good. If, however, the water is forced away or if bubbles appear through the water, the seal was compromised at some point and the food should be discarded.

Commercially canned food that is stored in a cool, dry place may remain good for many years past the dates stamped on the can. These foods are still safe to eat and most of the nutritional value remains as well. The color and texture may change, but the food is still safe.

Links to related posts:
Canning tomato sauce

For further reading:

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