5 - Sorting by colour in the food industry

Abstract

Food has colour, and good food is often a different colour from bad food. This in itself is not a very remarkable statement but its implications for the food industry are very significant. The human perception of colour has proved very effective in the determination of quality in many foods, and the sorting of food particles using the human eye and hand has been, and still is, widely practised. Machines designed to replace the hand sorter obviously need to duplicate some of the functions of the human eye, brain and hand. Automatic colour sorting is often referred to as ‘electronic sorting’, as it was the advent of electronics that made possible the duplication of the eye and brain functions. Experiments with automatic sorting equipment started immediately after World War II and colour sorting machines gained early acceptance in the food industry. Demand for automatic sorting machines continues to increase owing to the escalating costs of hand sorting coupled with the higher quality requirements being imposed on food producers. There is also an increasing realisation of the importance of sorting in the reduction of health hazards arising from contaminated food, whether due to the food itself or the presence of foreign bodies such as stones or wood, and the avoidance of associated product liability claims which are escalating dramatically in both number and value.