<<Disclaimer: Verify this information before applying it to your situation.>>
 
One thing you can do to prevent massive infestations is put all flours in
the freezer for a couple of days.  This kills any bugs that might be
present and keeps them from breeding and spreading. (Yes, I know it doesn't
get rid of any bugs that are there to begin with, but if you sift your
flour before using it, you should be able to detect any dead intruders.)
Even the best of brands/stores/people have bug problems once in a while.
Don't let it distress you too much.  I remember reading about travellers
who routinely tapped their bread or biscuits on the table to knock the
weevils out of them before eating it.
 
Jenny Herl              |   "The world has enough for everyone's need,
[log in to unmask]         |    but not enough for everyone's greed."
University of Illinois  |
Urbana-Champaign        |    --attributed to Mahatma Ghandi (1869-1948)