join is a good start, but we'd have to know more about the contents of your hash to answer any better. In general, you should be careful to escape any double-quotes in your data. I'd use something like:

print {$outfile} join ', ',
    map { qq|"$_"| }
    map { escape_quotes( $_ ) }
    @dataRow{qw( field1 field2 field3 field4 field5 ) };

...

sub escape_quotes
{
    my $string = shift;

    # a negative-lookbehind may be appropriate
    # to prevent double-escaping
    $string    = s/"/\\"/g;
    return $string;
}
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