There are residues and waste at all points in the food supply chain from initial production, through processing, handling and distributions to post-consumer waste from hotels, restaurants and individual houses.
It has been calculated that about a third of all food grown for human consumption in the UK is thrown away.
Food waste can be divided into dry waste and wet waste, however the majority is of relatively high moisture content.
- Agriculture also produces its own residues
- Many food materials are processed at some stage to remove components that are inedible or not required such as peel/skin, shells, husks, cores, pips/stones, fish heads, pulp from juice and oil extraction, etc
- Many manufactured foods and drinks, including beer, whisky and wine, and cheese and other dairy products generate large quantities of organic waste material. It has been estimated that up to 92% of ingredients used in brewing ultimately become waste, principally spent grains, and the dairy industry uses around 40 million m3 annually, mainly for cleaning, which produces effluent containing high levels of organic residues
- Food preparation on both the commercial and domestic scale yield residues and waste, used cooking oils and food that has had to be disposed of because it has gone bad, for health and safety reasons or because it is surplus to requirements. UK households alone produce about 5 million tonnes of kitchen waste annually