Comparative Study of Antimicrobial Effects of Lemon Oil and Peel Extract against Food-Spoilage Microbes

The aim of the present investigation was to assess and compare the antimicrobial activities of the lemon (Citrus sinensis) peel extract and lemon oil against common food borne pathogens and to study their potential as food bio-preservatives. The antagonistic activity of lemon peel extract and lemon oil was studied against common food borne pathogens like Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Bacillus subtilis, Bacillus sp. , Listeria monocytogenes, Micrococcus luteus, Escherichia coli, Klebsiella sp. and Pseudomonas aeruginosa by agar well diffusion assay. The fungal species were Rhizopus sp., Rhizomucor sp., Aspergillus fumigatus, Alternaria sp., Aspergillus niger, Aspergillus sp. and Penicillium sp. It was found that amongst bacteria, Staphylococcus aureus followed by S. epidermidis and Bacillus subtilis (with an inhibition zone diameter of 14mm, 12mm and 12mm respectively) was most sensitive towards lemon peel extract; amongst fungus, the lemon peel extract was most effective against Alternaria sp., and Rhizopus sp. (with an inhibition zone diameter of 25mm and 16mm respectively). In contrast, the lemon oil exhibited wide range of antimicrobial activity against both groups of bacteria (maximum zone of inhibition against Bacillus mycoides and other Bacillus cereus 33mm and 29mm respectively) and against fungi Rhizopus sp., and Aspergillus sp. (33mm and 27mm respectively). Thus the above study depicts that antimicrobial activity of lemon oil is much better than its lemon peel extract and has potential to be used as food bio preservative.