The federal government has a rule about how supermarket bacon can be packaged, Bloomberg News reports:
The U.S. Department of Agriculture, which regulates bacon and other meat products, spells it out like so: "Packages for sliced bacon that have a transparent opening shall be designed to expose, for viewing, the cut surface of a representative slice...for shingle-packed sliced bacon, the transparent window shall be designed to reveal at least 70 percent of the length (longest dimension) of the representative slice, and this window shall be at least 1-1/2 inches wide."
That regulation went into effect in 1973.
It's a fine little example of how deep is the federal government's reach into obscure and mundane aspects of the daily lives of Americans and the economy, and of how (as is often the case) the Nixon administration is to blame.