Filth tests

Microscopic examination of foods for contaminants such as hairs, rodent and bird droppings, and fragments of insects and feathers. They serve as an index of hygienic processing and handling. They support regulatory enforcement and supplier verification where visible contamination indicates systemic failures. Analysts use flotation, sedimentation and staining techniques to isolate light filth (insect fragments, hairs) from product matrices before microscopic counting. These labour-intensive tests remain the regulatory gold standard for sanitation assessment of cereals, spices, nuts and chocolate, complementing rapid hygiene indicators like ATP.