Comparison of three methods for determination of crude protein in meat: collaborative study.

A study was designed to compare the Kjel-Foss automated macro-Kjeldahl method and a block digestion-steam distillation method. The official AOAC Kjeldahl method was used as a reference procedure. Six products with a crude protein range of 10-30% were analyzed by 23 laboratories. Five laboratories analyzed the samples by the official AOAC method, 8 laboratories used the automated Kjel-Foss method, and 11 laboratories used the block digestion with steam distillation method. Standard deviations for each product and each method for both repeatability and reproducibility are given. The block digestion-steam distillation method has been adopted official first action.