Effect of laser and ultraviolet rays on the fate of some parasites and pathogens in freshly eaten vegetable foods


Laboratory experiments were conducted for vegetable salad samples which contaminated with Staphylococcus aureus , E.coli ,and Giardia lamblia . These samples were exposured to Lazer (diod of 800 nm w length) and UV( of 245 nm w. length) , for specific intervals for the aim to know the fate of these microorganisms in order to be sure for the safety of this kind of food , which considered as a dangerous pathways for the consumer health. The contaminated salad samples were exposed to Laser and UV rays for up to 5 and 25 minutes intervals respectively. Bacterial and parasite viable cells were detected in the exposure samples by the plate count method. The results shown that there is a 100 % and 99.7 % reduction of Staphylococcus aureus bacteria viable cell that exposed to five minutes Lazer and 25 minutes UV rays respectively . However, E.coli bacteria reductions were less affected by these rays .As shown with 5 minutes laser and 25 minutes UV exposure intervals , the reductions were 97.6 % and 96.7 % respectively. Giardia lamblia parasite, also shown 100 % and 91.4 % reduction for the same exposure time with laser and UV rays respectively