The grep function in Perl is not the same as the Unix utility grep. Your best bet is to open each file in @cgafiles for read and do a pattern match on each line:

foreach my $item (@cqafiles) {
  open CQAFILE, "<$item";
  while (<CQAFILE>) {
    next unless /^CQA_STATUS,/;
    print FILE $';
  }
}
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-imran