So, just what is Salisbury steak?
Salisbury steak is a dish made from a blend of minced beef and other ingredients, which is shaped to resemble a steak, and usually is served with gravy / brown sauce. Hamburger steak is a similar product, but differs in ingredients. Salisbury steak was invented by an American physician, Dr. J. H. Salisbury (1823–1905), an early proponent of a low-carbohydrate diet for weight loss; the term “Salisbury steak” has been in use in the United States since 1897. The dish is popular in the United States, where it is traditionally served with gravy and mashed potatoes or noodles.
So, it was invented by a low-carb pioneer and is now “traditionally” served with mashed potatoes or noodles.
Anyway, nothing makes a food less appealing than reading its standards of identity:
The USDA standards for processed, packaged “Salisbury steak” require a minimum content of 65% meat, of which up to 25% can be pork, except if defatted 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, vegetables (onion, bell pepper, mushroom or the like), binders (can include egg) and liquids (such as water, milk, cream, skim milk, etc.). The product must be fully cooked, or else labelled “Patties for Salisbury Steak”.
The standards for hamburger limit the meat to beef only, and of skeletal origin only. Salt, seasonings and vegetables in condimental proportions can be used, but liquids, binders and/or extenders preclude the use of the term “hamburger” or “burger”. With these added, the product is considered “beef patties”.