United States Department of Agriculture standards for processed, packaged “Salisbury steak” require a minimum content of 65% meat, of which up to 25% can be pork, except if de-fatted beef or pork is used, the limit is 12% combined. No more than 30% may be fat. Meat byproducts are not permitted; however, beef heart meat is allowed. Extender (bread crumbs, flour, oat flakes, etc.) content is limited to 12%, except isolated soy protein at 6.8% is considered equivalent to 12% of the others. The remainder consists of seasonings, fungi or vegetables (onion, bell pepper, mushroom or the like), binders (can include egg) and liquids (such as water, milk, cream, skim milk, buttermilk, brine, vinegar etc.). The product must be fully cooked, or else labeled “Patties for Salisbury Steak”.