$re = '/(?=.*Apple)(?=.*Car)(?=.*Bat)(?!.*(?:,|^)(?:(?!Apple|Bat|Car).)+(?:,|$))^.*$/m';
$str = 'Bat, Car, Apple
Other, Bat, Car, Apple
Car, Bat, Apple
Car, Other, Bat, Apple
Apple, Car, Bat
Apple, Car, Bat, Stick
Bat, Car
Apple
Car, Apple, Bat';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php