my $mentioned = 0;
FILE: for my $file ( @files ) {
  LINE: for my $line ( @lines ) {
    /Joe Bloggs/ and ++$mentioned and last FILE;
  }
}
return $mentioned;

##</code><code>##

my $mentioned = 0;
FILE: for my $file ( @files ) {
  check_file($file, \$mentioned);
}
return $mentioned;

...;

sub check_file {
  my ($file, $mentioned) = @_;
  LINE: for my $line ( @lines ) {
    /Joe Bloggs/ and ++$$mentioned and last FILE;
  }
}