Chicken processing: impact, co-products and potential

Processing poultry results in considerable waste and/or by-products. Assuming a 70% yield during processing, the aggregate of waste from processing chickens for meat globally is 45.9 million tons. The nitrogen in processing waste and by-products globally is 1.3 million metric tons; equivalent to 49% of nitrogen in poultry excreta globally. If yield increased to 80%, as seen in the USA, there is a concomitant reduction in processing waste. If this were extended globally, there would be a 19.1 million metric ton reduction in processing waste. The global cost of processing chicken has been calculated as 51.3 x 10 9 MJ (equivalent to 0.06% of agricultural/food energy usage). The environmental costs of processing include energy, high quality (potable) water usage (estimated at about 30 litres per bird) and large quantities of organic solids and ‘dirty’ water as by-products together with contamination of surface and of ground water. There is a case for viewing poultry waste as a resource. These co-products could be used as human foods, high protein animal feed ingredients (after rendering), high value health related products ( e.g. collagen, hyaluronic acid and chondroitin sulphate), bioenergy ( e.g. biodiesel) and other products. The following review focuses on estimating the amount of processing waste and approaches to reduce processing waste, such as increasing yield and considering waste as a resource or, at least potential, co-product.