Overview
The authors bought 21 dried black soldier fly larvae products sold in the US as backyard poultry treats over 2023 and 2024 and had them analyzed blind by a contract laboratory. Arsenic, cadmium and lead were found in every sample. Products labeled as Chinese origin averaged about 25 times more lead and 8 times more arsenic than North American products, although the table’s p values do not show a significant difference.
Key numbers
- Lead: overall mean 648 ppb, range 23 to 4,930 ppb; Chinese-origin mean 784 ppb versus North American 31.0 ppb (Table 1).
- Arsenic: overall mean 414 ppb, range 30 to 2,620 ppb; Chinese-origin 511 versus North American 62.0 ppb (Table 1).
- Cadmium: overall mean 232 ppb, range 40 to 734 ppb (Table 1).
- Mercury was detectable in only one sample (maximum 15.9 ppb) (Table 1 and text).
Methods (brief)
Retail packages were subsampled and sent blind to an accredited laboratory. Arsenic, cadmium, lead and mercury were measured by AOAC methods 2011.19, 993.14 and 2015.01 (ICP-MS), with detection limits of 2.5 to 10 ppb. Results are means, SEM and ranges on an as-sold basis.
Evidence Fitness
These products are animal feed for poultry, not food sold for people, so the study is a proxy for edible-insects: it shows what dried larvae on the retail market can carry, not what people eat. The groups are small (4 North American products), group counts add to 22 against a stated 21, and the authors’ employer sells a competing larvae product (declared). It is still one of the few retail surveys with lead and arsenic ranges for dried insect larvae.