Proba Así:
El codigo quedaría:
Código PHP:
$length = 1000;
while ( ( $data = fgetcsv( $handle, $length) ) !== FALSE )
{
$num = count($data);
for ($c=0; $c < $num; $c++)
{
$cadena_final = $cadena_final.$data[$c].",";
}
}
fclose($handle);
echo $cadena_final;