Journal of Food Quality and Hazards Control

2-12

Authors: M. Strateva, G. Penchev, D. Stratev

Background: Freezing is a common and ancient method for preservation of foods which is applicable both under household and industrial conditions. The objective of the study was to establish histological and microbiological changes in dorsal and abdominal muscles of rainbow trout (Oncorhynchus mykiss) after freezing once and twice. Methods: Forty-five fresh rainbow trout specimens were distributed into three groups of 15 fish each. The first group was subjected to histological and microbiological analysis immediately after delivery at the laboratory. The second fish group was frozen at -18 °C for 15 days, while the third group of fish was frozen at -18 °C for 15 days, thawed and frozen again at -18 °C for 15 days. Data were analyzed using GraphPad InStat 3 software. Results: After freezing once, muscle fibers with intracellular void spaces were observed and retained stable peripheral boundary. In some muscle fibers, the endomysium boundaries were visible and with retained integrity. After freezing twice, damages and deformities were observed resulting in completely destructured muscle fibers. Large void spaces among the muscle fibers and bundles were greatly the result of shrinking and grouping of fibers and the laceration of endomysium and perimysium internum. Total microbial count and Enterobacteriaceae count had no significant differences (p>0.05) between fresh, frozen once, and frozen twice trout. Conclusion: Muscles of rainbow trout (O. mykiss) are histologically damaged to a greater extent after freezing twice and thawing. However, microbiological indicators had no change significantly after freezing once and twice.

21-27

Authors: Z. Yousefi, M.R. Rezaeigolestani, G. Javadzade Moghtader

Background: Drying is the one of the oldest methods for increasing the shelf life of food products. The objective of the present study was evaluation of effect of different drying temperatures on drying time and storage quality parameters of in-shell hazelnut. Methods: Hazelnuts were dried as a thin layer at three temperatures (40, 50, and 60 °C). The time required for drying and quality parameters (lipid and protein content, acidity, and peroxide value) were evaluated. Besides, sensory and oxidation evaluations were performed in order to evaluate the effect of the drying temperatures on quality of hazelnuts before and after 6-month storage. Data were analyzed by SPSS software (V. 16.0). Results: The mean drying times at 40, 50, and 60 °C were 29.75, 25, and 20.25 h, respectively. In fact, an inverse significant (p<0.05) relationship was observed between temperature and time of the hazelnuts drying process. The mean protein content of the hazelnuts dried at 40, 50, and 60 °C were 13.06, 12.83, and 13.62 (% dry basis), respectively. Lipid content of the samples were significantly (p<0.05) increased with drying temperature. The lowest acidity and peroxide values were recorded for the samples dried at 60 °C with the values of 0.15% oleic acid and 1.3 meq/kg, respectively. Sensory results showed that all of the treated hazelnuts were acceptable after six months storage. Conclusion: The evidences of the present study point that in-shell hazelnuts drying at temperature of 60 °C can lead to production of good quality products.

34-40

Authors: A. Al-Mariri, R. Ismail, A. Allaham, B. Alobeid, L. Alhallab

Background: Essential Oils (EOs) are natural metabolic products of plants that contain a condensed chemical hydrophobic liquid compounds. The aim of this study was to evaluate inhibitory effects of EOs of Cinnamon zeylanicum and Myristica fragrans against Brucella abortus 544 inoculated in fresh Baladi cheese. Methods: Fresh Baladi cheese was manufactured from experimentally contaminated milk with B. abortus 544 in combination of EOs of C. zeylanicum or M. fragrans. Cheese samples were periodically subjected to further microbiological surveys at different storage times (0, 1, 24, 48, 72, and 96 h). The inhibition zone diameter and Minimum Inhibitory Concentration (MIC) against tested strain were also determined. Statistical analyses were conducted by GraphPad Prism Statistical Software. Results: The inhibition zone diameter of the paper disk were 9.5±0.5 and 16±0.57 mm at 1% concentration of M. fragrans and C. zeylanicum EOs, respectively; and 15±0.28 and 21±0.76 mm at 5% concentration of M. fragrans and C. zeylanicum EOs, respectively. The values of inhibition zone diameters were significantly (p<0.0001) different between the two selected concentrations of 1% and 5% for the studied EOs. Also, anti-Brucella activity of C. zeylanicum was significantly (p<0.0001) more than that of M. fragrans EO. Conclusion: Due to the appropriate anti-Brucella activity, C. zeylanicum EO could be applied as an effective natural preservative in the production of fresh Baladi cheese. Conversely, using M. fragrans EO could not protect the fresh Baladi cheese against Brucella.

45-49

Authors: Z. Ayubi, A.A. Jafari, S.A. Ayatollahi-Mousavi, H. Jafari, M. Panddeh

Background: Zataria multiflora Boiss. (Avishan-e Shirazi), as an Iranian endemic plant, belongs to the Lamiaceae family and may be used as a food preservative. This study aimed to detect potential genotoxic effects of Z.multiflora extract. Methods: Hydro-alcoholic extract of Z. multiflora was prepared. Human B lymphocytes were treated with 1% extract within 3 and 24 h. Sterile Phosphate Buffered Saline (PBS) and cisplatin were used as negative and positive controls, respectively. DNA damage profiles were examined using comet assay (Single Cell Gel Electrophoresis). Data were statistically analyzed by SPSS software v. 21. Results: No statistically significant (p=0.071) DNA damage was observed in B lymphocytes treated with either Z.multiflora extract or PBS after 3 and 24 h. However,there was a statistically significant difference (p=0.0001) between DNA damage in B lymphocytes that treated with cisplatin and Z. multiflora after 3 and 24 h. Conclusion: The comet assay used in the current study showed that Z. multiflora had no genotoxic effect.