Hello --

Very few brands of commercially-produced lactose, and no brands of
butter, are actually casein-free.  Most commercially-produced lactose
is MOSTLY free of casein, but it's expensive to get that last bit of
casein out of the lactose, so most places don't bother.  WHy?  Because
for most purposes a little bit of casein won't matter.  (Think about when
you separate eggs, retaining just the yolk.  A little bit of white always
remains with the yolk, but for cooking purposes that little bit of white
doesn't make a difference.)

For people with a casein allergy, though, that little bit of leftover casein
can make a HUGE difference, and therefore products with lactose in them are
NOT recommended.  (If your reaction isn't life threatening, feel free to
experiment, of course.)

Similarly, butter is composed primarily of dairy fat.  However, much of the
taste of butter comes from everything BUT the fat in dairy, including
casein.  I don't know of anyone with a casein allergy who can go near butter
safely.  You can, of course, try clarified butter (ghee), but you should do
it yourself, rather then purchasing a commerically-available variety, to make
sure that ALL the casein is really clarified out.  (There was a thread
about ghee a couple of years ago that you may be able to find... It explained
the procedure and the risk.)

I would not trust any company that said its lactose was completely casein-free.
Ask instead for the brand of lactose that they purchase and talk to the
lactose supplier directly.  You'll probably discover that some casein is,
in
fact, left in because it makes commercial sense to do so.

I hope this helps,
--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.

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