Although there are some twenty States in the U.S. that have food product dating laws the Federal government has little regulation concerning food product dating except for infant formulas and some baby foods. It does, however, require that if a manufacturer puts a calendar date on a food product it must also put wording to the effect of "use by" or "best before" next to it to explain what the date means. This is called "open dating" which is to say that it is a plain, easy to read calendar date rather than "closed or coded dating" that must be deciphered. Another date also commonly seen is the "sell by" date. While not as useful for food storage, it does have importance for day-to-day fresh food purchases.
Because the Federal government has so few food product dating standards manufacturers use their own to determine acceptable shelf lives. For the most part, they are based upon changes in texture, appearance, taste and cooking qualities. When a food item begins to exhibit signs of aging that would make it unappealing to customers then it is considered to be at the end of its marketable shelf life. Look for statements such as "use by", "best if used by", "best if used before" or similar wording to find this date. For shelf stable and frozen products it must include both the month, day and year. These dates are useful for determining how long a product can be retained in the storage program before it should be rotated out. When a food begins to undergo taste and appearance degradation the nutrient content will have begun to seriously fade and the time will have come to use it up so it can be replaced with fresher stock. If the product was properly preserved and not subjected to extreme storage conditions it is not unsafe to use after this date. If there is nothing to replace it with it may be kept, but its palatability and nutritive content will just continue to degrade.
Fresh food items such as meat, milk and eggs use a "sell by" date which simply means that the item should not be purchased beyond that date. Products using this date type are only required to use the day and month. Provided that it was properly transported and stored, an item kept past this date is not unsafe to use, but will begin to exhibit signs of aging that will make it unappealing and should be frozen or consumed shortly thereafter.
NOTE: The shelf life of any food, whether indicated with a "use by" or "sell by" date or found on some chart, is predicated upon assumed storage conditions. If the actual storage conditions are different from the assumed storage conditions then the shelf life will naturally vary. As is explained in Section I: Time, Temperature, Moisture, Oxygen and Light, environmental storage conditions have a major impact on the length of time any foodstuff will remain palatable, nutritious and even whether it will remain safe.
As a general rule, when a shelf life is given, it is for conditions of 70° F in a dark, dry location unless stated otherwise. Be sure to read the fine print on any shelf life chart you may come across to see what its values are predicated upon. There are some floating around giving shelf lives of foods in storage temperatures as low as 40° F. At that temperature you would expect to keep your fresh butter, eggs and milk, but very few have the ability to keep any significant amount of canned goods in so cool a storage area.
Regardless of what the date or chart may indicate, if storage conditions have been very poor then a food will become non-nutritious, unpalatable, perhaps even unsafe to eat even if its listed time is not yet up. An example of this would be keeping egg salad at room temperature for several hours at a picnic. The eggs may have been laid yesterday, but you are taking your chances if you eat it. Never put blind faith in any date. Always keep in mind that they are predicated on unspoken assumptions. IF THE CONTAINER IS BULGING, MOLDED, FOUL SMELLING OR SPEWS LIQUID WHEN OPENED, THROW IT OUT! But throw it out safely so that children and animals cannot get into it.
Please see Section III: Spoilage for further information
Misc.Survivalism FAQs maintained by Alan T. Hagan, athagan@sprintmail.com
Copyright ©1996, 1997, 1998, 1999. Alan T. Hagan. All rights reserved.
Excluding contributions attributed to specific individuals all material in this work is copyrighted to Alan T. Hagan and all rights are reserved. This work may be copied and distributed freely as long as the entire text, my and the contributor's names and this copyright notice remain intact, unless my prior express permission has been obtained. This FAQ may not be distributed for financial gain, included in commercial collections or compilations or included as a part of the content of any web site without prior, express permission from the author.