What products commonly contain dairy?

Bakery products, baking powder, butter, buttery spreads, cream sauces, cake mixes & toppings, canned tuna & meats, chocolate, condensed or evaporated milk, cream, creamed foods, custard, ice cream, instant desserts, instant or other pudding mixes, Junket, margarine, mashed potatoes, powder or dried milk, salad dressings, scrambled eggs, skim milk, and many desserts.

Not so obvious sources

If you want to avoid dairy completely, look for these words on package labels: 

albumin, casein, caseinate, curds, lactoglobulin, lactose, milk protein, milk solids, nougat, rennet, butter, whey (powder, protein, or syrup), yogurt, and lactic acid starter culture. 

These are all sources of dairy and may be irritating if you are sensitive.

The rule of thumb is to make your own food from scratch with fresh, natural ingredients. OR buy foods that have 3-5 ingredients, not more. Avoid processed foods. If the label is a bunch of chemical mumbo-jumbo, aside from finding some traces of DAIRY there , you are not doing your body any good by eating something that came from what looks like a chemical lab.