Eugenia supra-auxillaris (family Myrtaceae) leaves were explored for their total phenolic content and antimicrobial activity against some food borne pathogens for its probable use as a food preservative. The total extract of E. supra-auxillaris exhibited significant antimicrobial activity against Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa and Aspergillus niger at concentration of 100 mg/ml. Upon fractionation, the ethyl acetate fraction appeared to be more potent than the n-butanol fraction in inhibiting bacterial and fungal growth and had higher polyphenolic content. Three phenolic compounds were isolated and identified from the bioactive fraction. The impact of microencapsulation of the ethyl acetate fraction with sodium alginate (2%) was investigated. The micro-encapsulated fraction retained its antimicrobial activity as low as a concentration of 25 mg/ml. Since the tested pathogens are frequent candidates causing food-borne illnesses, it would be interesting to investigate the potentiality of their possible application in food to increase shelf life or promote safety.