Nitrogen factors for pork: a reassessment

Abstract

The nitrogen factor (the percentage of fat-free nitrogen in a sample) for pork was estimated from a sample of 60 carcases from four commercial abattoirs. The sample included carcases defined as pork weight (52 ± 2 kg), bacon weight (72 ± 4 kg) and heavy weight pigs (92 ± 8 kg). The nitrogen factor for the lean with intermuscular fat in the whole side was 3.50 (estimated for the national average pig used for processing). Comparable figures for joints were 3.49 (leg), 3.38 [neck (collar)], 3.42 (hand), 3.66 (loin) and 3.50 (belly). These factors are similar to those published by the Analytical Methods Committee in 1986 but are based on a larger sample more representative of the current pig population in Britain. It is recommended that they now become the basis for the standard factors. As factors change significantly with the mass of carcase and fatness, it will be appropriate to revise the estimates as the average national pig population changes. Fat, moisture, ash, hydroxyproline and nitrogen contents in each joint and the side are also reported in this paper.