That doesnt mean they don't enter the human food chain. If you buy processed meat products then I would bet somewhere in there is the offal you don't see on the butcher's counter or supermarket shelf. Sausages, pork pies, doner kebabs would perhaps be the most likely places I would guess. And can you still buy 'beef paste'? Nothing is going to be wasted, perhaps Google 'Mechanically Recovered Meat' to check.
There is a big difference between eating sausages on the off chance it contains some liver alongside the pulverised bones, cartildge and gristle and eating good quality offal.
Below is the minerals found in Beef liver... I very much doubt many Richmond sausages can claim that!
Copper
An 81-gram slice of cooked beef liver contains 11,800 micrograms of copper. This amount supplies well over 100 percent of the 900 micrograms that the Institute of Medicine's Food and Nutrition Board recommends for adult men and women on a daily basis. Copper aids in collagen and red blood cell synthesis and promotes the function of the immune and nervous systems. Eating copper-rich foods may lessen your risk of osteoporosis and osteoarthritis, though be aware that regularly consuming more than 10,000 micrograms of copper a day may result in kidney or liver damage. You can prevent copper toxicity by following a varied diet that includes high-copper foods like beef liver only occasionally.
Phosphorus
Adults need 700 milligrams of phosphorus each day, and a serving of cooked beef liver supplies almost 40 percent of this requirement. Phosphorus regulates the levels of nutrients like magnesium, vitamin D and zinc. It helps with the growth, development and maintenance of bones and teeth and is necessary for the production of DNA and RNA. According to the University of Maryland Medical Center, inadequate phosphorus intake is rare in the United States since many Americans get more than they need from animal products like meat and carbonated beverages. To balance out your phosphorus levels, be sure to include plenty of calcium-rich foods in your diet -- consuming too much phosphorus and too little calcium is linked to a higher risk of heart disease and osteoporosis.
Selenium
Each 81-gram slice of prepared beef liver has 26.6 micrograms of selenium, or about 48 percent of the required daily intake for adults. Selenium has antioxidant properties that enable it to inhibit the DNA-damaging ability of free radical compounds. Its presence is also necessary in order for the immune system and thyroid gland to work properly. If your diet lacks adequate selenium, you may be more likely to develop cancer, rheumatoid arthritis, heart disease and recurrent infections.
Zinc
The body needs zinc to promote the healing of skin wounds, to help regulate hormones and glands in the endocrine system and to aid in blood coagulation. A serving of beef liver contains 4.25 milligrams of zinc, which fulfills 38 percent of the RDA of zinc for men and 53 percent of the RDA for women. Adequate zinc intake may help prevent age-related macular degeneration and neurological disorders like attention deficit hyperactivity disorder.
Iron
Men should have 8 milligrams of iron each day, while women require 18 milligrams daily. Consuming an 81-gram slice of cooked beef liver provides men with 62.5 percent of their recommended daily intake and women with 27.7 percent of their RDA. Iron plays a vital role in red blood cell production and in the formation of the main source of cellular energy, adenosine triphosphate, or ATP. A diet lacking sufficient iron may lead to anemia and impaired neurological development, especially in children.