Microcrystalline cellulose from rice straw bleached pulp was prepared using solar energy then, it modified to synthesize novel nontoxic antimicrobial cellulose (MAMC) derivative which utilized in the manufacture of stirred yoghurt. Different concentration of (MAMC) was used and compared with stirred yoghurt (control). Microbiologically, chemically, organoleptic and physical properties of resultant stirred yoghurt were studied. Also, the antimicrobial activity of the different concentration of MAMC was assayed against bacterial and fungal pathogenic strains. Results revealed that MAMC was shown good effect against all the pathogenic strains especially at 1.00% concentration which the diameter of inhibition zone ranged from 10 to 15 mm. Addition of MAMC had slightly increased on the viability of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Bifidobacterium bifidum. Moreover, all treatments free from coliform, yeast and mold compared with control when fresh and during cold storage. Moreover, Additive MAMC impose various degrees of inhibition against the growth of some pathogenic and fungi that cause food contamination and spoilage. The acidity and SN/TN of stirred yoghurt treatments increased with prolonged storage period but declined with increasing the ratios of MAMC addition. Sensory evaluation showed that 0.5% of MAMC was the best concentration that had a highest total score during storage. It was recommended that use of MAMC as natural preservatives of stirred yoghurt improve the overall acceptability at ratio 0.50% and extended the shelf life of this product.