美国权威机构解说食品日期问题，由于生产厂家对食品日期的不同标示及消费者的认知差异，

据美国农业部USDA估计，每年导致美国有30%的食品被错误地扔垃圾箱，白白浪费了。

What Date-Labeling Phrases are Used?
There are no uniform or universally accepted descriptions used on food labels for open dating in the United States.  As a result, there are a wide variety of phrases used on labels to describe quality dates.

Examples of commonly used phrases:

• A "Best if Used By/Before" date indicates when a product will be of best flavor or quality.  It is not a purchase or safety date.
• A "Sell-By" date tells the store how long to display the product for sale for inventory management.  It is not a safety date. 
• A “Use-By" date is the last date recommended for the use of the product while at peak quality. It is not a safety date except for when used on infant formula as described below.
• A “Freeze-By” date indicates when a product should be frozen to maintain peak quality. It is not a purchase or safety date.

欲知详情：

https://www.fsis.usda.gov/wps/wcm/connect/19013cb7-8a4d-474c-8bd7-bda76b9defb3/Food-Product-Dating.pdf?MOD=AJPERES