The term 'corned beef' refers
to the 'corns' of salt used to preserve the meat. Meat is treated
with large grains of salt (corns) in a process known as salt-curing.
Corn is used to describe any small hard particles or grains, in this
case, salt. That is why corned beef tastes salty. The salt draws
water out of the meat via osmosis, making it more difficult for
microorganisms to breed in the meat.