Nut cleaning is the removal of foreign matter including sticks, stones, husk fragments, dust and empty shells from in-shell nuts using sieves, air separators and destoners before cracking or packing.
In trade practice
Processing lines typically combine rotary or flat-deck sieves to remove oversized and undersized debris, air classifiers to lift dust and light material, and destoners to separate dense foreign matter by specific gravity. Metal detection is a mandatory food-safety step before any packing stage and is required by most EU retailer and food-manufacturer codes of practice. A common gap is the absence of a documented cleaning validation record, which auditors from private certification schemes routinely request. Stone contamination reaching the shelling stage damages cracking machinery and increases shell-fragment levels in the kernel.
In a specification
Specifications may require a maximum foreign-matter tolerance by weight and confirmation that metal detection equipment is calibrated and logged at defined intervals.