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J Nutr Sci Vitaminol (Tokyo). 2006 Apr;52(2):157-60.
Antibacterial activity of citrus fruit juices against Vibrio species.
Tomotake H, Koga T, Yamato M, Kassu A, Ota F. Iida Women's Junior College, Nagano, Japan.
Bacteria of the genus Vibrio are Gram-negative bacilli,Several species of Vibrio are important human pathogens; most disease- causing strains are associated with gastroenteritis, Notable pathogen Vibrio include 'V. cholerae (the causative agent of cholera), V. parahaemolyticus (a type of food poisoning associated with undercooked seafood), and V. vulnificus (another seafood- associated, food poisoning strain).
Lemon, lime and sudachi juices were tested for antibacterial activity against seven strains of Vibrio species. All juices were effective in inhibiting the growth of the Vibrio strains. Citric acid, the major organic acid in these juices, was found to be responsible for inhibiting the growth of Vibrio parahaemolyticus. Sauce prepared from sudachi juice showed a strong bactericidal activity against Vibrio parahaemolyticus, whereas the sauce adjusted to higher pH values had no bacterial activity. Diluted sudachi juice or citric acid solution also had antibacterial activity independently. These results suggest that citrus fruit juices are effective in preventing infection with Vibrio species.
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Bactericidal activity of lemon juice and lemon derivatives against
Vibrio cholerae.
Clinical Microbiology Department, Instituto de Microiologia Di. Luis C. Verna, Facultad de Bioquimica Qumica y Farmacia, Universidad Nacional de Tucman, Argentina.
Food products can be possible vectors of the agent responsible for
cholera epidemics, because some of these products allow Vibrio
cholerae O1 to develop to concentrations above the dangerous level.
This study deals with the behaviour of essential oils, natural and
concentrated lemon juice and fresh and dehydrated lemon peel against
V. cholerae O1 biotype Eltor serotype Inaba tox+. Our aim was to
evaluate whether these products, used at different dilutions,
exhibit bactericidal or bacteriostatic activity against the
microorganism, 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 and essential oils inhibited V. cholerae
completely at all studied dilutions and exposure times. Fresh lemon
peel and dehydrated lemon peel partially inhibited growth of V.
cholerae. Freshly squeezed lemon juice, diluted to 10(-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) produced
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.