From everything I have read lactic acid starter cultures MAY contain milk proteins if they are derived from milk. However, lactic acid starter cultures may be derived from vegetable sources such as beet and corn. So if you see it on a label and have no way to call the company and get a straight answer (assuming someone at the company is knowledgeable enough to answer your question and/or will actually respond to you) assuming that the product contains dairy is the safest route to go.
Most companies don't indicate on packaging what the source of the lactic acid starter culture is, however, I know of a least one that does. Wellshire Farms does a line of meats including turkey sticks and pepperoni. On the label for their turkey sticks it states that the lactic acid starter culture is derived from corn. I personally think they are tasty though Max thinks they are too spicy. I haven't looked at a package of pepperoni but you can search their products with elimination of your specific allergen and pepperoni does come up as dairy free. If you are in doubt please call the company but (this is mainly for elisha (Hi! Thanks for introducing yourself)) may be worth a shot.
The Food Allergy Labeling and Consumer Protection Act only covers labeling for foods under FDA inspection. It does not cover anything under USDA, hence meat. Which is why companies don't have to disclose the source of their lactic acid starter culture. Here is a good FAQ sheet about FALCPA.