Crustacean shells (shrimp, crab, lobster)
Exoskeletons of shrimp, crab and lobster, a by-product of seafood processing.
Characteristics
- Composed mainly of calcium carbonate, protein and chitin.
- Chitin, a nitrogen-containing polysaccharide, is the raw material for chitosan.
- Proportions vary by species; crab shells are especially rich in minerals.
- Used dried and ground, or fermented, as a source of calcium and nitrogen.
Role in the preparation: Dried, ground shells supply calcium, nitrogen and chitin to compost, bokashi or ferments; acids dissolve their carbonates.
Caution: Dry quickly to limit odours, handle with gloves because of sharp fragments, and keep in mind the risk for people allergic to shellfish.
Documentary information: this is neither a recommendation for use nor a plant-protection or veterinary claim. Check your country's regulations before any use.