Once you have found the files you are interested, just open them and use m// (or whatever) to search for what you're interested in.

Or use File::Find::Rule's grep predicate if you're interested in which files match (as the poster is) rather than exactly what they contain. :)

The following exactly fulfills the poster's spec:

my @files = File::Find::Rule
    ->file()
    ->grep(qr/\Q$word\E/)
    ->in(@directory);
[download]

Makeshifts last the longest.