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Background & aim:The use of bio preservative or strains as sources are interesting for food bioprocessing technologist,   and is one of the latest methods to increase the shelf life of food by the health authorities . The present study aimed to investigate the antibacterial activity of supernatants of yeasts isolated from Richal as a traditional dairy product and fermented dairy products in Armenia.

Methods: In the present experimental study, the purified supernatant of 77 strains of Armenian yeast products and 12 strains from Iranian Richal were isolated. The purified supernatant were tested against three strains as food spoilages bacteria includes: B. subtilis 17-89, B. Thuringensis17-89, S.typhimuium G-38 , on 3media in 2 condition as aerobic and anaerobic. The inhibition zone of the supernatant were measured   and reported as antibacterial activity. Data were analyzed using statistical tests.

Result: A total of 89 strains of yeasts, three species of Rachel and 9 strains of Armenian products (13.5% percent) had demonstrated antibacterial activity. T86 strains of Armenian yeasts and FA1 (25) of Rachel had shown more ZOI and antibacterial activity on three media at both aerobic and anaerobic conditions. Comparing the mean of ZOI upon three corruption factors, Rachel strains were significantly different (p <0.05). The highest and lowest effect was observed on Bacillus subtilis effect and Salmonella typhimurium respectively.

Conclusion: The results indicated that the yeast strains isolated in anaerobic and aerobic conditions on spoilage bacteria had antibacterial activity effect. Thus, it could be concluded that adding the yeast or its supernatant to food as a bio preservative, may introduce a operative product to the food industry.

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Background & aim: Infertility and its individual and social problems are one of the main and important issues and concerns of couples and about half of all infertility is related to men. Therefore, the aim of this study was to determine the effect of adipose tissue-derived mesenchymal stem cell supernatant (SPAS) product in reducing sperm damage during freezing and thawing.

Methods: The present descriptive-analytical cross-sectional study was performed in 20 infertile men referred to Qom University Jihad Infertility Treatment Center in 2017. All of these men had asthenospermia. Samples were prepared from these individuals and then pre-freeze measurements such as; Sperm viability, DNA fragmentation, malondialdehyde and oxidative stress were assessed. After that, the stem cells were frozen with the supernatant product and the same previous studies were performed on the defrosted sample. Data were analyzed using one-way analysis of variance.

Results: The results of the present study indicated that sperm survival increased after supernatant defecation. Sperm survival at 25 and 50% concentration was higher than freezing conditions (p <0.05), but no significant difference was seen in DNA doses and oxidative stress in any of the doses (p> 0.05).  The amount of malondialdehyde also changed. The amount of malondialdehyde in SPAS and untreated samples was significantly different from the frozen samples (p <0.05).

Conclusion: Due to the positive effect on sperm and improving their quality after defecation using fat-derived mesenchymal stem cell supernatant, it may be used as a suitable preservative alone or in combination with other supplements. It seems that the increase in sperm viability in the spasm environment was due to the presence of growth factors in this supernatant.