Effect of natamycin and potassium sorbate on the growth of Penicillium commune

Abstract

The effect of selected concentrations of antimicrobials potassium sorbate and natamycin against the growth of different strains of penicillium commune was studied. Fungal growth was optically observed using microtiter plate wells. In 180 μl of broths containing the antimicrobial in different concentrations were added 20μl of the strains of P. commune and incubated in temperatures ranging from 5oC to 29oC for up to 14 days. A yellow soft cultured cheese was used for the coatings which were prepared using alginate, potato starch and whey protein isolate as a base matrix with strains 240.0063 or 240.0068 of P.commune. Control samples were included carrying H2O and a mold strain. They were stored for 9 days at 5oC and 15oC. The pH was measured foe the natamycin containing broth and was found ranging from 4.7 to 5.9 and aw ranged from 0.933 to 0.947. The results of natamycin containing microtiter plate wells showed that the most resistant strain in all temperatures was strain 240.0064; the strain with the best mold growth inhibition was strain 240.0063. The micropiter plate well containing potassium sorbate did not inhibit mold growth. On day 9, the coating at 5oC had not any mold growth; the cheese coatings stored at 15oC had no inhibition of mold growth. The present study provides useful data on the inhibition of P.commune on cheese which can be used by the industry.