EFFECT OF ADDING EXTRACTS OF MINT AND THYME ON THE GROWTH OF MICROORGANISMS IN WHITE SOFT CHEESE MANUFACTURED IN LABORATORY

Abstract

This study aimed to detect the effect of adding two plant extracts namely; Spearmint (Mintha spicata L.) and Thyme (Thymus vulgaris) at different concentrations on some microbiological and sensory properties of white soft cheese manufactured in the laboratory. Cow milk was used in processing the cheese. Control cheese manufactured by using the rennet only, while the other cheese treatments were made by adding separately different concentrations (10, 20, and 30 ml/100 grams of curd) of mint and thyme extracts to the curd. The produced cheese samples were studied microbiologically and organoleptic ally during storage at intervals (fresh, 3, 6, 9, and 12 days) at 4 C° in the refrigerator. The results of the microbiological tests revealed, the superiority of cheese samples produced by adding the plant extracts in extending the shelf-life of the cheese compared to control samples. Using higher concentrations (20 and 30) of either mint or thyme extract was found to be the most effective in decreasing the total bacterial count, and in earlier disappearance of coliform and staphylococcus compared to the control cheese. The yeast and mold appeared late during the storage in the treated cheese, while they appeared earlier in the control. The results of the organoleptic properties during cold storage revealed, that, all samples of cheese manufactured in this study got scores which made them acceptable by the consumers. It is also found that, there was no negative affect as a result of adding the two types of extracts on the sensory properties of the manufactured white soft cheese.