Alex's explanation of kosher is pretty good.  For an overlapping explanation,
more complete for those whose concern is allergy but less complete for those
whose concern is religious, visit my web page.  Look for the section
"Kosher is Your Friend".

State laws regarding the use of the word "kosher", by the way, vary.

Kosher dill pickles, for what it's worth, are made using kosher salt (which
you can buy at many supermarkets).  Kosher salt is used to make meats kosher;
it isn't covered by any special religious laws except that it has to be
sufficiently pure to do its job.

I didn't know whey was bitter.  Interesting ...
--Beth Kevles
  [log in to unmask]
  http://web.mit.edu/kevles/www/nomilk.html -- a page for the milk-allergic
  Disclaimer:  Nothing in this message should be construed as medical
  advice.  Please consult with your own medical practicioner.