Fresh cut fruits and vegetables spoiled by number of bacterial pathogens. In this experiment the low cost, nontoxic and pollution free chitosan nanoparticles were prepared in the laboratory level, characterized by FTIR, XRD and SEM and confirmed the presence of nanoparticles. Various concentrations of nanoparticles (10µg, 20µg, 50µg, 100µg and 150µg) were prepared and used to investigated the antibacterial activity against one positive (Bacillus sp) and one negative bacteria (pseudomonas sp) respectively.  The results showed that zone of inhibition against Bacillus sp and Pseudomonas sp were noted at 50µg, 100µg and 150µg concentrations respectively. These results suggested that chitosan nanoparticles can be used as effective growth inhibitors for food spoilage microorganisms. It is confirmed that this pollution free low cost technology is suitable for arresting food spoilage bacteria effectively. Hence, the present study indicated that the non-toxic chitosan nanoparticles may be considered as a food preservative. Hence this preliminary study which will create further research in this new field.