en Public Health Public Health پژوهشي Original Article <div style="text-align: justify;"> <div><span style="font-size:14px;"><span style="font-family:Times New Roman;"><strong>Background:</strong> Fermented food products are an inherent element of the human diet throughout the world owing to their health benefits. Kefir grains are a starter culture containing yeast and bacteria, which are classified as fermented dairy products. The present study aimed to investigate the effects of low-dose X-ray irradiation on kefir grains and the fermentation constituents.<br> <strong>Methods:</strong> Five grams of kefir grains was added to nine dishes. Three dishes were irradiated to 40cGy, three dishes were irradiated to 80cGy X-ray, and three dishes remained non-irradiated as the control group. The chemical properties of the kefir samples (lactic acid, protein, fat, and lactose concentrations) were investigated after X-ray irradiation using standard methods.<br> <strong>Results:</strong> The contents of lactic acid, protein, and lactose increased in the samples irradiated to 80cGy X-ray (<em>P</em> < 0.05), while their fat content decreased (<em>P</em> < 0.05). No significant differences were observed between the 40cGy X-ray samples and controls.<br> Conclusion: According to the results, 80cGy X-ray irradiation affected the kefir grains and increased their protein, lactose, and lactic acid, while decreasing the fat content, which makes milk consumption more convenient for those with high blood lipid levels.</span></span></div> </div> Kefir, X-ray irradiation, Chemical properties 173 176 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-70-5&slc_lang=en&sid=1 Faranak Saghatchi Saghatchif@zums.ac.ir 100319475328460010401 100319475328460010401 Yes Department of Radiology, School of Paramedical Sciences, Zanjan University of Medical Sciences, Zanjan, Iran. Hamed Rezaeejam hrezaeejam@yahoo.com 100319475328460010402 100319475328460010402 No Department of Radiology, School of Paramedical Sciences, Zanjan University of Medical Sciences, Zanjan, Iran. Oldooz Sadralashrafi o.sadralashrafi@gmail.com 100319475328460010403 100319475328460010403 No ACECR Zanjan Branch, Zanjan Academic Center for Education Culture and Research, Zanjan, Iran.