Hi -

As other people have mentioned, the reason for people allergic to dairy
protein to avoid lactose is the risk of cross-contamination.  Most "
"lact" ingredients do come from dairy, but some may not.  Sodium
stearoyl lactylate, for example MAY be dairy-derived, but may also be
derived from non-dairy sources.  Check with the manufacturer if you need
to know for certain.

As for kosher labellings:  The major certifiers (such as OU) are about
as reliable as you can get, commercially.  They are sensitive not only
to Jewish law (which means knowing the source of each ingredient and
keeping dairy ruthless away from meat or parve products) but they are
also sensitive to allergy issues.  Allergy issues do, in fact, require
slightly different handling than kosher issues.

My web site contains a carefully researched and vetted section on kosher
labellings that should (hopefully) answer any questions brought up on this
list.  It also mentions that sad fact that local certifiers are less
sensitive to allergy, which means that your local kosher bakery may not, in
fact, be safe place to shop if you have milk allergy.

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.