Degradation of Potassium Sorbate by Penicillium Species

Molds were isolated from natural and processed Cheddar cheese previously treated with potassimn sorbate.When potato dextrose agar fortified with up to 8,400 ppm potassium sorbate and adjusted to pH 5.3 to 5.5, served as the substrate, Penicillium roqueforti, a mutant of P. roqueforti~ Penicillium notatum~ Penicillium frequentans~ and Penicillium cyaneo-fulvum (all recovered from cheese), were able to grow in the presence of up to 5,400, 7,100, 2,300, 2,800, and 1,800 ppm potassium sorbate, respectively.All of the penicillia studied depleted sorbate from liquid culture media; highest