Fruit juice is one of the best drinks that provide a major part of the body's needs for vitamins and is considered a suitable source to compensate for wasted water, but if health standards are not met, it is considered as a potential source of contamination. The purpose of this research is to evaluate the effect of ultraviolet radiation on the microbial load of apple, grape and orange juice during the radiation period.

500 ml of fruit juice including natural apple, grape and orange juice were randomly provided from fruit juice supply centers in the Shahrekord city and then the fruit juice was passed through device to perform tests (manufactured by Pars UV company, model 1X). The microbial load measurement method was carried out in accordance with the standard-4207 of Iran's National Standard Organization and using serial dilution method, and 4 and 3 dilutions of the tubes were prepared. Then, they were radiated in zero, 30, 60 and 120 second treatments. The data was statistically analyzed by SPSS software and the one-way ANOVA method was used to evaluate the data.

Based on the statistical analysis, it was found that the highest lethality was related to the time of 120 seconds in all three types of fruit juice and there was a significant relationship between the duration of UV radiation and the reduction of the microbial load in the fruit juice.

According to the analyzes obtained from the UV method on the reduction of the microbial load of fruit juices, it could be said that if this method is radiated effectively to liquids, then it can have a significant effect on reducing the bacterial contamination.