my @kwlist = qw(foo bar baz qux);
my $kwre = join('|',@kwlist);
my @items = getfromdb("select id,text from table"); # I have a sub that does this
foreach my $i (0..$#items) {
    my ($id,$text) = @{$items[$i]};
    my $count = 0;
    while($text =~ /$kwre/g) {
        $count++;
    }
}