Evaluating the Effectiveness of UV Irradiation on Reducing Microbial Load of Some Highly Consumed Seed Nuts

Nut's seeds can be a source of contamination with various types of microorganisms and so some of them are important for public health.  Therefore, with regard to household consumption of those type of seeds and their application in food industries, and also due to the fact that some of them are imported from other countries so they may have the possibility of microbial contamination from the source, therefore the purpose of this study was to evaluate the efficacy of UV irradiation in reducing the microbial load of some consumed seed nuts. Six types of beans including sunflower seeds, watermelon, pumpkin, walnut, pistachio, and hazelnut were randomly sampled in bulk from Tehran retail market. Testimonials were tested by methods in the Iranian national standard and food and drug organization standards. Subsequently, infected seeds were irradiated in 1, 2 and 3 layers of thickness and time at 5, 10 and 15 minutes in a UV cabinet with a wavelength of 254 nm and subjected to appropriate microbial tests. According to the results, the irradiation time and thickness were significantly affected by the total microbial count of pistachio, walnut and hazelnut (p<0.01). Also,  it has a significant effect on the coliform count  of pistachio, walnut, hazelnut seeds, pumpkin seeds, sunflower and watermelon, and the mould count of pistachio, walnuts and hazelnuts, sunflower seeds and a watermelon (p<0.01). It had less significant effect on the number of molds in pumpkin seeds (0.01<p).