Application of lime (Citrus aurantifolia) juice to drinking water and food as a cholera-preventive measure

The protective activity of lime juice against cholera was suggested in a recent case-control study from Guinea-Bissau. On the basis of these findings, we investigated the vibriocidal properties of juice from lime (Citrus aurantifolia) fruits added to well water, tap water, and food samples. Well-water samples showed initial pH values from 3.5 to 4.9 whereas water samples from municipal or private taps showed initial pH values between 7.5 and 8.3. A 5-log reduction in Vibrio cholerae O1 counts to 100 CFU/ml of well water was shown for two test strains after exposure to 0.5% lime juice (pH 3.3) for 12 min. In tap water, no significant reduction in CFU of V. cholerae was found after exposure to 0% (pH 8.3) and 0.5% (pH 5.6) lime juice whereas exposure to 1.0% lime juice (pH 4.4) for 120 min caused a 5-log reduction to 100 CFU/ml of tap water for the test strains. A 3-log reduction of V. cholerae was found in food samples containing 3.5% and 5.0% lime juice after 120 min exposure. Our results show that during epidemics of cholera in areas without safe sources of drinking water, juice from citrus fruits added to water and food in palatable concentrations may be appropriate measures in reducing the transmission of cholera. However, local characteristics of the water, in particular its alkalinity, should be considered before applying this measure