Indigenous knowledge systems and practices in harvesting, processing, preservation, and microbial safety of edible insects in Tanzania

Edible insects are increasingly recognized as a sustainable protein source, yet systematic evidence on the safety and efficiency of indigenous processing practices remains limited. This study combines ethnographic surveys with microbiological analysis to document traditional harvesting, processing, and preservation methods for edible insects across nine ecological zones in Tanzania. Findings reveal edible insect harvesting practices through wild harvesting, which varied by insect type, habitat, and seasonal availability. Unexpectedly, 30.9% of respondents reported raw consumption of edible insects. A wide diversity of insect specific processing methods was observed, including dry toasting, frying, boiling, sun drying, and smoke drying, reflecting adaptations to insect morphology, perishability, and intended use. While thermal processing practices were generally effective in elimination of major pathogens ( Salmonella spp., Escherichia coli and Listeria monocytogenes ), preservation challenges related to drying efficiency, post-processing handling, and storage were evident. Although most samples complied with East African Standards (EAS 1186:2023), sun-dried and toasted products exhibited high total viable counts and yeast and mold levels. No formal training to handlers was recorded, and processing practices were primarily transmitted orally and experientially through storytelling and observation. These findings demonstrate the potential of indigenous knowledge as a foundation for safe insect food systems, while identifying priority interventions such as improved drying infrastructure, hygienic handling, and Hazard Analysis Critical Control Point (HACCP) aligned protocols to support commercialization and regional trade without eroding cultural integrity.