Volume 1: Findings and Conclusions
2. Setting the context
Renderers

135 The rendering process involved the crushing and heating of the raw material supplied from slaughterhouses (see vol. 13: Industry Processes and Controls). The process led to the evaporation of the moisture in the material, which then enabled the fat, known as 'tallow', to be separated from the remaining high-protein solids, known as 'greaves'. The greaves were further processed by pressing, centrifuging or by solvent extraction in order to remove more tallow. The resultant protein-rich material was then ground into meat and bone meal (MBM). In the 1980s both tallow and MBM had a good commercial value.

136 Rendering is not a new industry. It has existed in some form for centuries, producing tallow for candles and soap. However, it was only at the beginning of the 20th century that the production of MBM for animal feed became important. The production and use of MBM steadily increased throughout the first half of the century and, when national self-sufficiency became an important issue during the Second World War, Regulations actually prescribed its use in animal feed. The production of MBM and tallow continued to increase after the war.

137 From the 1960s onwards there was a change in technology from older-style 'batch-processing' systems to faster and more efficient high-volume 'continuous rendering' systems. By the 1980s most plants used a continuous rendering system, and the economies of scale forced older and smaller plants to close down, leaving fewer than 100 rendering plants in England, Wales and Scotland at this time. Two firms dominated the market, with Prosper De Mulder processing 64 per cent of the red meat waste in England and Wales by the early 1990s, and William Forrest & Son (Paisley) processing 74 per cent of the red meat waste in Scotland.

138 During the 1950s the process of solvent extraction became the preferred method of extracting tallow from greaves. The process involved pumping a benzene-based solvent through a heated vessel of greaves so that the tallow dissolved in the solvent. The tallow was then separated out from the solvent and the greaves were heated further so as to vaporise and remove any solvent that was still present. By the late 1970s this method was being phased out because of the increased price of solvents, the risk of fire and explosion entailed in their use, and because animal feed manufacturers wanted to buy MBM with a higher fat content.

139 Up until the 1980s the rendering industry was virtually unregulated in terms of quality control and production methods (see vol. 14: Responsibilities for Human and Animal Health). In 1981 Regulations came into force to ensure the microbiological safety of processed protein. In the context of increasing deregulation by government, it was decided that the best way to do this was by testing the microbiological safety of the finished MBM, rather than by prescribing set production procedures. In effect this gave renderers a lot of freedom in determining their preferred production processes and it allowed for a diversity of processes in different plants. Advice about new Regulations reached renderers through the UK Renderers' Association (UKRA), the primary trade association representing renderers' interests.

140 In the 1980s the end-products of the rendering process - MBM and tallow - were widely used in the manufacture of a diverse range of products. MBM was used as a protein source in animal feed, and in fertiliser. Tallow was used in the manufacture of many human foods, such as edible fats, and when further processed into glycerine it was used even more widely, for example in jellies and in baking. It was also used in animal feed and pet food, as well as in pharmaceuticals, cosmetics and in a range of industrial products. Meanwhile, gelatine, produced from the hide and bones of animals in a completely separate industry and process, was also used in a wide range of products including human food, the coatings of tablets, cosmetics, glue, bone china and photographic chemicals.