en تخصصي Special Original article Original article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><strong>Background: </strong>Sarcocystosis is one of the most distributed parasitic diseases over the world, caused by <em>Sarcocystis</em> spp. In this study, we assessed the effect of electron beam irradiation on the viability of <em>Sarcocystis</em> spp. in beef.&nbsp;<br> <strong>Methods:</strong> Experimental beef groups were irradiated by four different electron beam doses of 1, 2, 3, and 4 kGy, at intervals of 0 and 24 h after irradiation, then the samples were transferred inside a sterile microtube containing RNA<em>later</em> solution and stored at -20 &deg;C till next steps. RNA extractions and cDNA synthesis were done using the related kit in order to detect the presence of the 18S ribosomal RNA region. Relative quantification was carried out using SYBR Green Real time Polymerase Chain Reaction. The statistical analysis was done using SPSS 16.0 by Tukey&rsquo;s and Kruskal-Wallis tests.<br> <strong>Results:</strong> Irradiation at zero time was not effective on viability of <em>Sarcocystis</em>, but at 24 h, irradiation doses of 3 (<em>p</em>=0.003) and 4 kGy (<em>p</em>=0.008) caused a significant reduction in <em>Sarcocystis</em> viability. Irradiation doses of 1 and 2 kGy had no significant (<em>p</em>>0.05) effect on <em>Sarcocystis</em> viability reduction. Also, no significant differences (<em>p</em>>0.05) were observed between irradiation doses of 3 and 4 kGy.<br> <strong>Conclusion:</strong> Electron beam radiation at dose of 3 kGy was effective as the optimal dose for the elimination of <em>Sarcocystis</em> spp. in beef.&nbsp;<br> <br> <strong>DOI:</strong> 10.18502/jfqhc.7.4.4846</span></span></div> Radiation, Sarcocystis, Red Meat, Survival, Microbial Viability, Real-Time Polymerase Chain Reaction 181 187 http://jfqhc.ssu.ac.ir/browse.php?a_code=A-10-92-1&slc_lang=en&sid=1 G. Eslami 0000-0002-4521-4059 No Department of Parasitology and Mycology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran S. Peletto No Istituto Zooprofilattico Sperimentale del Piemonte, Liguria e Valle d’Aosta, Via Bologna 148 - 10154 Torino, Italy M. Vakili No Department of Community and Preventive Medicine, Health Monitoring Research Center, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran S. Kargar samanekargar3@gmail.com 0000-0002-5517-6869 Yes Department of Food Hygiene and Safety, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran