A Preliminary study on antifungal activity of lactic acid bacteria isolated from different production stages of Lighvan cheese on Penicillium expansum and Rhodotorula mucilaginosa

摘要

AbstractAntifungal properties of 19Lactobacillus plantarumstrains isolated from Lighvan cheese during different production stages were evaluated againstPenicillium expansum(ATCC 36200) andRhodotorula mucilaginosa(ATCC 2503). To accomplish such comparison, culture-based methods including Lawn on the Spot and Well Diffusion were performed and strains with antifungal property were screened. From a pool of 19 strains, 10 ofLb. plantarumspp. exhibited antifungal activity againstPen. expansumand 11 of them againstR. mucilaginosa. Thereafter the effects of pH (ranged from 2 to 7) and temperatures (80?°C for 1?h, 100?°C for 10 and 30?min, and 121?°C for 15?min) were evaluated. AllLb. plantarumspp. maintained their inhibitory effect at pH of 2 and 3, while no inhibition was observed at pH of 7. Inhibitory effect intensity decreased by increasing the temperature/time duration of heating.Lb. plantarumC28 showed the highest thermal resistance and also with inhibitory activity of 160?(AU/ml) possessed the highest anti-fungal activity using titration test. The strains LF51, C24, LF49 and LF51, C24 exhibited anti-mold and anti-yeast activity respectively after a 20-fold concentration of the cell free supernatant againstPen. expansumandR. mucilaginosa. Inhibitory effects of all isolates were lost when subjected to proteinase K which implies their proteinaceous nature.]]>