Rapid assay to estimate calcium and phosphorus in meat and bone meal

Using a flotation/sedimentation technique, an assay was developed to provide a rapid estimate of the ash, calcium (Ca), an phosphorus (P) content of meat and bone meal (MBM). Thirty samples of commercially rendered MBM were assayed for Ca, P, and ash by standard procedures. Volume of bone was determined by sedimentation. When MBM is mixed with cholorform, the bone fraction settles to the bottom of a graduated cylinder, the meat portion floats to the surface, and fat is dissolved. Performing this procedure under standardized conditions (20 g MBM mixed into 60 mL chloroform in a 100-mL graduated cylinder) resulted in a highly significant (P < .01) relationship between volume of bone sediment (measured as mL) and percentages of Ca, P, and ash. Prediction equations to estimate Ca, P, or ash contents of MBM samples are: % Ca = 0.60 + 0.92 (mL bone), R-2 = .84 % P = 0.54 + 0.43 (mL bone), R-2 = .85 % ash = 6.87 + 2.21 (mL bone), R-2 = .83.