The effect of irradiation (0.5, 1.0, 1.5 Mrad) on the microbiological safety and stability of temperature-abused (27°C, 60 days) bacon cured with' 1.5% NaCl, 0.25% sucrose, 0.3% Na5P3O10 0.055% Na-erythorbate, with or without NaNO2 (40 μg/g) was determined. Unioculated bacon (120 μG/g NaNO2/g) had a sour odor within 13 days, and, if inoculated with ca. 2 C. botulinum spores/g, 73% of the samples became toxic within 60 days. Irradiation with 0.5 Mrad prevented spoilage of uninoculated bacon by virtue of reducing the aerobic plate count to <1.0/g; irradiation with 1.0 Mrad sterilized bacon. Pouches of bacon, inoculated with C. botulinum spores (2 spores/g), swelled and became toxic; development of swelling and toxicity was delayed by incorporation of NaNO2 (40 μg/g) or by irradiation with 0.5 Mrad. Irradiation with 1.0 Mrad decreased the number of swollen and toxic pouches. Irradiation with 1.5 Mrad prevented swelling and toxicity of bacon inoculated with 2 spores/g.