Colour sorting by optical detection is the process of separating food commodities into accepted and rejected streams based on colour signals, removing discoloured, immature or damaged pieces and improving lot uniformity for buyers.
In trade practice
Optical sorters use cameras or laser sensors calibrated to product-specific colour programmes; operators set acceptance thresholds to match buyer colour specifications for each crop or variety. For berries and stone fruit, underripe and overripe pieces are ejected in a single pass, while for pulses such as kidney beans, discoloured seeds linked to mould or field damage are removed. QA teams verify sorter performance by running reference samples and recording rejection rates; a sudden drop in rejects often signals a miscalibrated programme rather than a clean lot.
In a specification
A specification may state the permitted percentage of off-colour units by count or weight after sorting, referencing the buyer’s colour standard or an agreed visual reference card.