Bactericidal activity of lemon juice and lemon derivatives against Vibrio cholerae

Food products can be possible vectors of the agent responsible for cholera epidemics, because some of these products allow Vibrio cholerae O1 to devel op to concentrations above the dangerous level. This study deals with the b ehaviour of essential oils, natural and concentrated lemon juice and fresh and dehydrated lemon peel against V.cholerae O1 biotype Eltor serotype Inab a tox(+). Our aim was to evaluate whether these products, used at different dilutions, exhibit bactericidal or bacteriostatic activity against the mic roorganism, when present at concentrations of 10(2), 10(4), 10(6) and 10(8) colony forming units (CFU) ml(-1), and after different exposure times. 10( 8) CFU ml(-1) was considered an infectious dose. Concentrated lemon juice a nd essential oils inhibited V. cholerae, completely at all studied dilution s and exposure times. Fresh lemon peel and dehydrated lemon peel partially inhibited growth of V. cholerae. Freshly squeezed lemon juice, diluted to 1 0(-2), showed complete inhibition of V. cholerae at a concentration of 10(8 ) CFU ml(-1) after 5 min of exposure time; a dilution of 2 x 10(-3) produce d inhibition after 15 min and a dilution of 10(-3) after 30 min. It can be concluded that lemon, a natural product which is easily obtained, acts as a biocide against V. cholerae, and is, therefore, an efficient decontaminant , harmless to humans.