Avoid foods that contain milk or any of the following ingredients:

Butter, butter fat, butter oil, butter acid, butter esters 
Buttermilk 
Casein 
Casein hydrolysate 
Caseinates (in all forms) 
Cheese 
Cottage cheese 
Cream 
Curds 
Custards 
Diacetyl 
Ghee 
Lactoferrin 
Lactose 
Lactulose 
Milk (in all forms, including: condensed, derivative, dry, evaporated, milk from goats and other animals, low fat, malted, nonfat, powder, protein, skimmed, solids, whole) 
Milk protein hydrolysate 
Pudding
Recaldent® 
Rennet casein 
Sour cream, sour cream soilds 
Tagatose 
Whey (in all forms)
Half-and-half