African Journal of Biotechnology Vol. 4 (3), pp. 258-261, March 2005          
ISSN 1684–5315 © 2005 Academic Journals

Short Communication

Activity of essential oil and phenolic acid extracts of pepperfruit (Dennetia tripetala G. Barker; Anonaceae) against some food-borne microorganisms

B. O. Ejechi* and  D. E. Akpomedaye

Department of Botany and Microbiology,Delta State University, Abraka, NIGERIA

*Corresponding author.  E-mail: ejechiben@yahoo.co.uk.

Accepted 28 December, 2004

A previous report showed that the essential oil and phenolic acid extracts of pepperfruit (Dennetia tripetala) inhibited the growth of tomato-rot fungi. The study was subsequently extended to other food-borne microorganisms (Staphylococcus aureus, Salmonella sp. Pseudomonas aeruginosa., Proteus sp., Escherichia coli., Enterococcus faecalis., Serratia sp., Bacillus sp., Clostridium sp., Penicillium sp., Aspergillus flavus) isolated from food products. All the isolates were susceptible to the extracts with a minimum inhibitory concentration (MIC) range of 1.0-4.0 mg/ml. The essential oil inhibited the food-borne organisms better (MIC: 1.0-2.5) than the phenolic acid (MIC: 1.5-4.0). The challenge organisms in fresh, boiled or roasted beef, treated with the extracts were either not detected, declined significantly in number (p<0.05) or did not change significantly in population (p>0.05) after 7 days. A role for pepperfruit extracts in natural food protection is further indicated.

Key words: Essential oil, pepperfruit, dennetia tripetala, phenolic acid, food-borne microorganisms.