I read an interesting article a few days ago about how borax was used in the US as a meat preservative up through the early 20th century, along with more toxic substances like copper sulfate and formaldehyde. In those days there were no food safety regulations, so manufacturers used whatever they wanted.

Suspicious of the safety of these additives, a chemist from the U.S. Department of Agriculture formed volunteer "Poison Squads" to test if these substances were actually safe or not. The article discusses his work, and is worth a look.

"Death in the Pot": http://www.laphamsquarterly.org/essays/death-in-the-pot.php?...