In my cheesemaking experience, I have been able to use both a home made starter, commercial bulk starters and commercial DVI. What are these I hear you ask? On this post I will go back a step and define the differences and what a starter culture is.
A starter is a collection of bacteria that begin a fermentation process. In this case they are lactic acid producing bacteria or lactobacillus. There are many ways of making a starter culture as you are harvesting and using bacteria that are naturally present in raw milk anyway.