Ash and calcium as measures of bone in meat and bone mixtures

Bone content of mechanically recovered meat is usually controlled by settin g calcium limits, but these limits may allow more bone in some products bec ause calcium content of fresh bone is variable. Studies involving depositio n of energy, nutrients, and minerals are also dependent on ash or calcium t o determine bone content of carcasses. However, ash and calcium, which is 3 7% of bone ash, varies by age of animal, presence or absence of tissues suc h as marrow or cartilage that are associated with bone, and state of bone h ydration. Literature that reports ash content of bone and factors associate d with its variability is the focus of this review. Based on the literature reviewed, a conversion factor of 4.5 for calcium percentage to fresh corti cal bone percentage from round bones of cows, fed beef, lambs, pigs and hen s is recommended. A conversion factor of calcium percentage to fresh bone p ercentage of 5.0 is recommended for all veal and broiler bones and for flat bones. (C) 2000 Elsevier Science Ltd. All rights reserved.