Green, Grey and Brown Discolouration

Meat pigments shift colour when their iron state, ligand or protein environment changes. Cure pigments can also be oxidised or disrupted.

Green colour may result from oxidising compounds, microbial metabolites or heat-related pigment chemistry. Pattern, odour and process history are needed for interpretation.

Oxygen exposure, light, insufficient cure reaction, ageing and heat can produce grey or brown zones.

Residual oxygen, film permeability, vacuum loss and light exposure alter colour after slicing and packing.

Compare unopened and opened packs, surface and centre, and affected and normal units. Review cure, heat, pH, oxygen and microbiology.

Correct the chemical, microbial or package cause. Colourants or stronger smoking should not be used to conceal unexplained discolouration.