The effects of iron, temperature, and presence of botulinal spores or sodium ascorbate on depletion of nitrite level were determined in meat and model systems. Higher temperature and presence of botulinal spores definitely increased nitrite depletion in a meat system. Added hemoglobin also significantly increased nitrite depletion, while ferrous iron and ferric iron did not significantly decrease nitrite level in a meat system. High temperature and presence of sodium ascorbate increased nitrite depletion in a model system. Only ferrous iron significantly decreased nitrite level in the absence of ascorbate, while ferric iron, heme iron, and ferritin iron did not decrease nitrite level in the absence of ascorbate. Ferrous iron, ferric iron, and heme iron decreased nitrite level in the presence of ascorbate, while ferritin iron did not decrease nitrite level in a model system.