Giardiacidal activity of lemon juice, vinifer and vinegar on Giardia intestinalis cysts

The giardiacidal efficacy of simple disinfecting materials, ie lemon juice, vinifer, and vinegar, for uncooked foods with Giardia cysts was investigated to help travelers in Giardia-endemic areas. The cysts were obtained from stools of individuals with Giardia intestinalis infection by modified sucrose gradient procedure. A pooled batch of 3 x 10(4)/ml Giardia cysts was made from all specimens. The cysts were kept at 4 degrees C until use. Before each experiment, the number of cysts was determined by hemocytometer. Two sets of Eppendorf tubes were used for the experiments, one set at 4 degrees C and one at 24 degrees C. One thousand microliters each of lemon juice, vinifer, or vinegar was poured into each tube, and 1,000 microl of Giardia cysts were added. Variables were disinfectant materials, temperature, and time of exposure. Cyst viability 140 was determined by eosin inclusion procedure. Viability of at least 250 cysts in each tube at 0, 0.5, 1, 2 and 3 hours after the beginning of the experiments was determined. The mean giardiacidal activity at 4 degrees C after 3 hours for lemon juice, vinifer, and vinegar was 18.9, 12.8, and 28.4%, and at 24 degrees C, 28.3, 16.2, and 40.6%, respectively. In conclusion, the giardiacidal activity of vinegar was more than the other materials, and as exposure time and temperature increased, giardiacidal activity also increased; the highest giardiacidal activity of vinegar was at 3-hours exposure at 24 degrees C.