It depends on the brand. The original Garden Burger brand Ingredients:
VEGETABLES (BUTTON MUSHROOMS, ONIONS, CRIMINI MUSHROOMS, PORTABELLA MUSHROOMS), COOKED BROWN RICE (BROWN RICE, WATER), ROLLED OATS, MOZZARELLA CHEESE (PASTEURIZED PART-SKIM MILK, CULTURES, SALT, ENZYMES), WATER, BULGUR WITH WATER FOR HYDRATION, PARSLEY, CHEDDAR CHEESE (PASTEURIZED MILK, SALT, ENZYMES, CULTURES, ANNATTO FOR COLOR), CONTAINS TWO PERCENT OR LESS OF YEAST EXTRACT, NATURAL FLAVOR, MODIFIED VEGETABLE GUM, SALT, MUSHROOM EXTRACT, GARLIC POWDER, AUTOLYZED YEAST EXTRACT, SPICES, CITRIC ACID, MALTED BARLEY, NATURAL BUTTER FLAVOR, WHEY, DEHYDRATED ONION, ANNATTO FOR COLOR, DEHYDRATED MUSHROOMS, GUAR GUM, NATURAL SMOKE FLAVOR, TURMERIC FOR COLOR, SOY LECITHIN.