By-products from the food and dairy industries

Abstract

For the purpose of this paper I intend to include within the term ‘by-products’ all those materials that arise from the food industries which are not consumed by the human population of the United Kingdom. Some of these materials are not acceptable as part of the human diet, or, if acceptable, find no ready market. Other materials are inedible, perhaps by humans and other animals, but can be converted into acceptable food or feed whilst yet others which are edible and acceptable are wasted in processing, storage, transport, distribution and in the kitchen and dining room. It is impossible to give a figure for the annual amount of by-products and waste available but statistical evidence points to approximately 6 million tonnes of food, all of which is edible but not consumed. This figure does not include by-products which are not intended for human consumption such as abattoir wastes, whey and brewery wastes and cereal offals. The total figure is therefore larger and represents a considerable potential economic resource. (It must be observed however, that only a small fraction of these wastes and by-products can be economically utilized. Other speakers are dealing with animal slaughter, fish and cereal wastes and I will therefore give only passing attention to these materials.)About 40 million gallons of cheese whey are produced in the UK each year on the farm. Of this, about 12 million gallons are fed directly to pigs. Although it appears that heavy hog production and cheese making are often associated, disposal of whey on farm remains a problem, since the price fetched by whey may be only a quarter or less than the cost of transport. Disposal on land, where it can be useful as a fertilizer, can lead to pollution problems. Trials carried out by ADAS (Wolverhampton) on both beef and dairy cattle are promising. It has been shown that every kg of barley previously fed to dairy cattle can be replaced by 10 litres of whey at half the cost, making barley feed unnecessary. In diets for steers, calculations have shown that a litre of whey at 6% solids can replace 90g of compound for energy (Peacock, 1977).