need alternative for `fgrep --quiet'

I found the following error message in my log file:

  procmail: Executing " (formail -x From: -x Sender: | fgrep -iqf $FRIENDS)"
  fgrep: ERROR: Illegal option -- q
  procmail: Program failure (2) of " (formail -x From: -x Sender: | fgrep -iqf 
$FRIENDS)"

I'm not too familiar with UNIX but believe fgrep, at my ISP, does not allow the 
-quiet option. What may I use instead to make my recipe work?

Thank you.  --  Justin