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A Reassessment of Pork Nitrogen Factors - FA0127

Nitrogen factors are analytical factors used to measure meat and fish content (i.e. the amount of meat or fish used) in compound products, and added water in raw meat and fish, and their products. They are used by both enforcement labs (public analysts) to check (QUID) labelling claims on meat and fish content, and by industry to check their raw materials and finished products.

The UK market value of pork and pork products is around £3.7 billion. In addition to home production, a substantial amount of pork is imported to the UK from Europe especially Denmark and the Netherlands. Most of the imported pork goes into pork products or imported as ham or bacon.
The last extensive AMC study determining pork nitrogen factors of different joints and the overall carcase was published in 1991. Over the past 21 years, the genetics and methods of rearing pigs have changed. In addition, the average UK killing weights have also increased. In the 1991 study, pigs used in the study were killed at 50-70kg. Today, the kill weight for UK pigs is usually 78-80kg. Danish pigs are slaughtered around 82 kg and Dutch pigs at 90kg. In this study the nitrogen factors for the four main joints of pork used in pork products will be reassessed and compared to the values of nitrogen factors in the 1991 study.

40 samples of each of the 4 joints (leg, belly, loin and shoulder) will be collected over a period of 6 months sourced from the UK, Denmark and the Netherlands. The samples will be analysed for nitrogen, moisture, ash and fat, and subjected to statistical analysis. The resulting nitrogen factors for the four joints can be compared to those in the 1991 study. In addition the nitrogen factors for UK pork in the 4 joints can be compared to the same joints from Dutch and Danish pigs.

The factors obtained will permit industry to check their raw materials and also monitor the meat content of its products. The study will also ensure that there is no unfair competition between UK pork producers and those from Denmark and the Netherlands. The study will be published and can be used by enforcement to check meat content of pork products to ensure labelling of meat products is correct.
This study will reassess the nitrogen factors of 4 pork joints (leg, belly, loin and shoulder) for UK pork, and compare them with the factors used by enforcement and industry today, which were derived in 1991. It will also indicate whether genetic changes, husbandry and feeding regimes have changed the composition of UK pork. Also, accurate nitrogen factors will be derived for the same four Dutch and Danish pork joints to ensure that there is no unfair competition with home grown UK pork. These factors will also be used to verify meat content claims of the very large trade of imported Dutch and Danish bacon and ham.
The study will be overseen by the Royal Society of Chemistry Analytical Methods Nitrogen factors Sub-Committee, and published in a peer reviewed scientific journal.
Project Documents
• FRP - Final Report : FINAL REPORT FA0127   (2381k)
Time-Scale and Cost
From: 2012

To: 2013

Cost: £83,700
Contractor / Funded Organisations
Royal Society of Chemistry