Individual and combined effects of vanillin and potassium sorbate on Penicillium digitatum, Penicillium glabrum, and Penicillium italicum growth

The individual and combined effects of potassium sorbate and vanillin conce ntrations on the growth of Penicillium digitatum, P. glabrum, and P, italic um in potato dextrose agar adjusted to water activity 0.98 and pH 3.5 were evaluated. Inhibitory concentrations of potassium sorbate varied from 150 p pm for P. digitatum to 700 ppm for P. glabrum, and for vanillin from 1,100 ppm for P. digitatum and P. italicum and 1,300 ppm for P. glabrum. Fraction al inhibitory concentration (FIC) isobolograms show curves deviated to the left of the additive line. Calculated FIC index varied from 0.60 to 0.84. F IC index as well as FIC isobolograms show synergistic effects on mold inhib ition when vanillin and potassium sorbate are applied in combination.