Swiss cheese samples collected aseptically from private dairies were analysed for the presence of Penicillium citrinum and for the efficacy of antimycotic agents against P.enicillium citrinum. The spore suspension of Penicillium citrinumand antimycotic agents like pimaricin and potassium sorbate at specified concentrations were added to cheese and stored at 250 C for 21 days. The keeping quality of cheese was assessed at 0, 7, 14 and 21 days. On statistical analysis, pimaricin at 10 ppm concentration was found to be highly significant (P <0.01) over 5 ppm of pimaricin, 500 and 1000 ppm of potassium sorbate with regard to anti-mycotic effect.