Overview
House crickets at a commercial Italian insect farm were fed control diets or diets enriched with red or brown seaweed, then analyzed for cadmium, arsenic, lead, mercury, nickel, chromium and aluminum. Crickets bioaccumulated mercury (and arsenic on some diets), and brown seaweed raised arsenic, cadmium and mercury in the insects, but all regulated elements stayed below the EU limits the authors used.
Key numbers
- Control-diet crickets, wet weight: cadmium 0.032 ± 0.001, lead 0.018 ± 0.003, arsenic 0.024 ± 0.007 mg/kg (Table 3, trial 1).
- With 40% brown seaweed: arsenic 0.071 ± 0.007 versus 0.020 ± 0.001 mg/kg wet weight in controls; mercury 0.0028 versus 0.00166 mg/kg (Table 3, trial 2).
- Aluminum 4.0 to 15.9 mg/kg wet weight, the highest of the elements measured (Table 3).
- Mercury bioaccumulation factor above 1 in every group (1.25 to 2.88) (Table 2).
Methods (brief)
Freeze-dried crickets were microwave-digested and analyzed by graphite-furnace AAS; mercury by direct mercury analyzer, in a clean-room laboratory with DORM-2 reference material. Wet-weight values were back-referenced to fresh sample weight; n = 9 per group.
Evidence Fitness
Careful chemistry on farm-reared crickets of the species authorized as a novel food in the EU, but this is a short feeding experiment (7 or 15 days) with seaweed diets, not a survey of crickets on sale. Control-diet groups are the closest to ordinary farmed crickets. Use it for rearing-control evidence: seaweed in feed can raise arsenic and mercury.