Exploration is specific enough--by definition, it's an undertaking for the purpose of discovery. What's more, it's a better answer than "expedition," which is only a journey undertaken for a specific purpose. Military expeditions to defeat enemies, and commercial expeditions to trade are common throughout history, for example.
Pasteurization generally does not sterilize milk. You can sterilize milk for a much longer shelf life, but it changes the flavor and removes the beneficial bacteria as well.