Antimicrobial Activity of Echinophora platyloba Aqueous Extract on Gas- Producing Fungi in Doogh

Nowadays, the application of natural antimicrobials like plant extracts in food preservation is becoming popular and increasing. The aim of this study is to determine the effect of Echinophora platyloba (E.platyloba) aqueous extract on gasproducing fungi and sensory properties of doogh. For this reason, the concentration of 0% (Control), 0.125%, 0.25%, 0.5%, 1%, 2%, 4% and 8% of the extract were prepared. Five samples of doogh containing no preservatives or extract was purchased from manufacturer factories. Six types of mold and ten types of yeast were isolated from the samples. The isolated fungi were cultured in the plates containing different concentrations of E. platyloba aqueous extract. After determination of the effective concentration of the extract, the sensory properties of samples were evaluated using fivepoint hedonic scale.The results showed that the E. platyloba extract have antifungal properties and its effect against the yeasts was greater than molds. At the extract concentration of 8%, the count of yeasts decreased to zero and the half of mold growth was inhibited. Due to the negative effect on sensory properties of doogh at the extract concentration of 8%, it cannot be used as a preservative, but it might be applied as an aromatic or flavoring agent at lower concentrations in this product.