Abstract

Antibacterial activity of peel essential oils of various Pakistani Citrus species viz. fewtrell’s early [Citrus reticulata (L.) var. Tangerine], orange [C. reticulata (L.) var. Mandarin], mousami [Citrus sinensis (L.)  var. Mousami], malta [C. sinensis (L.) var. Malta], grapefruit (Citrus paradisi Macf.) and Eureka lemon (Citrus limon L.) were evaluated against food-borne bacteria namely Escherchia coli, Salmonella typhii, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas fluorescence, Proteus myxofaciens, Staphylococcus epidermidis and Streptococcus sp. The peel essential oil yield of the C. reticulata var. Mandarin, C. reticulata var. Tangerine, C. sinensis var. Malta, C. sinensis var. Mousami, C. limon and C. paradisi were 0.32, 0.24, 0.22, 1.21, 0.05 and 0.21%, respectively. The disc diffusion method was used to evaluate the inhibition zones of bacterial growth at two concentrations (5 and 10 ul) of the oil and results were compared with cefipime, a commercial antibacterial agent. Essential oils of C. reticulata var. Mandarin showed highest antibacterial activity followed by essential oils of C. lemon. Essential oils of C. paradise andC. sinensis var. malta exhibited least antibacterial activity. Among the various bacterial species, S. typhii and P. myxofaciens were found most susceptible to various Citrus peel essential oils. Present study concludes that essential oils of C. reticulate var. Mandarin have a broad spectrum antibacterial activity against food spoilage bacteria.  

Key words: Antibacterial, Citrus spp, essential oils, food spoilage bacteria.