Since thousands years medicinal plants had been the main natural source of folk and modern drugs. Capparis spinosa is one of strongest resistant wild plant to adverse conditions in the Mediterranean area. It has a noticable medicinal and nutritional value. This study aims to determine the antimicrobial activity of alcoholic extracts of flower buds,  fruits and leaves of  Capparis  spinosa  against a variety of microorganisms causing food poisoning and spoilage [(bacterial strains including Bacillus subtilis ATCC 14085, Bacillus cereus DSMZ 345, Escherichia coli O157:H7 ATCC 51659, Salmonella typhimurium ATCC 14028, and Staphylococcus aureus ATCC 6528), (yeast strains including Candida albicans ATCC 10231 and Geotricum candidum NRRL Y-552) and (fungal strains including Aspergillus niger ATCC 102, Aspergillus flavus ATCC 247 and Fusarium moniliform ATCC 206)]. Also, the possibility of using caper (Capparis spinosa) extracts as natural preservatives in foods production (tomato ketchup) is another objective. The obtained results showed that the strongest antimicrobial activity of both caper buds, fruits and leaves extracts were recorded against St. aureus ATCC 6528  and B. cereus DSMZ 345 for all studied concentrations, (with diameter of inhibition zone ranged from 16 to 26 mm and, 16 to 25mm, respectively)  while the lowest antimicrobial effect was recorded against G. candidum NRRL Y-552 t and S. typhimurium ATCC 14028, with diameter of inhibition zone ranged from 0 to 15 mm and, 12 to 17 mm, respectively. On the other hand, the maximum antifungal effect of all studied extracts was recorded against F. moniliform ATCC 206, while the minimum antifungal effect was recorded against A.  niger ATCC 102. In the same time, sensory properties (texture, taste, color, flavor and Over all acceptability) and total plate count of produced ketchup by adding different concentrations of the previous extracts were evaluated, and the results suggested that, both caper buds, fruits and leaves extracts could be applicable in food processing as natural preservatives.