In a large saucepan, heat the milk to 180 degrees F. Remove from the heat and cool to 72 degrees F. Add the starter culture to the milk and stir thoroughly. Cover and let sit at 72 degrees F. for 12 to 15 hours, or until the milk has set into a firm curd. Ladle the curd into cheesecloth-lined colander and drain 1 to 6 hours to desired consistency. At this point, salt or fresh herbs may be added to cheese. Refrigerate until ready to use.