A soft drink is a non alcoholic beverage typically containing water often carbonated and a flavoring agent. Microbial contamination of soft drinks usually originates during the production process. Orange based soft drink was evaluated for microbial contamination. The aim of the present project was to evaluate the microbiological stability of soft drinks for annihilation of spoilage bacteria. It was found that at 0.06% citral concentration the growth of Escherichia coli and Pseudomonas aeruginosa was totally inhibited after thermal treatment for 15 minutes. On the other hand Enterobacter aerogenes and Klebsiella spp. were inhibited at 0.09% citral concentration after thermal treatment for 5 minutes and 10 minutes respectively. The addition of the citral in combination with the thermal treatment progressively increased the frequency of not spoiled test tubes. Finally, citral strengthened the antimicrobial action when used in combination.