**DO-AHEAD TIP: Marinate pork for 8 hours (see recipe).
In a large zipper-topped plastic bag, combine olive oil, soy sauce, vinegar, lemon juice, Worcestershire sauce, garlic, parsley, mustard and pepper.
Add tenderloin slices, seal bag and turn to coat; refrigerate for 6 to 8 hours.
Preheat grill to MEDIUM-HIGH. Remove tenderloin pieces from marinade; discard marinade.
Grill pork for 15 to 20 minutes, turning halfway through cooking time, until internal temperature reaches 160 degrees; serve.