Potassium sorbate was incorporated at the rate of 0.1% in a lot of butter at the time of working. Samples of butter were analysed each week for 6 weeks for mold, coliform bacteria, free fatty acids and thiobarbituric acid values after storage at different temperatures (20 C, 27 C, 37 C). Potassium sorbate inhibited the mold in all the samples at the end of 5 weeks at -20 C. Coliform counts increased rapidly in control samples at 37 C; however, consistently lower coliform counts were recorded in the butter samples containing potassium sorbate.