Reducing SO₂ in fresh pork burgers by adding chitosan.

The use of 0.02 or 0.05% chitosan is proposed to reduce from 450 to 150 mg kg⁻¹ the SO₂ required to preserve pork burgers aerobically packed and stored at 2 °C for up to 21 days under retail display conditions. The effects of chitosan and/or sulfite addition and the storage time were determined in fresh (color deterioration, lipid oxidation, pH, total viable counts, Escherichia coli and coliforms, Salmonella, appearance and odor) and cooked (appearance, odor, flavor and texture) burgers. The addition of either 0.02 or 0.05% chitosan was not detected by sensory analysis, and extended the shelf life of low-SO₂ burgers from 7 to 14 days. Chitosan enhanced the preservative effects of sulfite at a low dose, acting on the main causes of meat deterioration (bacterial spoilage, color stability and lipid oxidation), and provided good sensory properties to fresh and cooked pork burgers.