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The purpose of this study was to measure sensory, chemical, microbial, freshness and shelf life of packaged Tilapia fillets by vacuum and modified atmosphere methods compared to fillets packaged by aerobic method at refrigeration. Methods: Treatments consisted of Tilapia fillets packaged by vacuum and modified atmosphere methods. The fillets packaged by aerobic method were as control samples. Findings: TVB-N, PV, TBARS, total bacterial count, Staphylococcus and Pseudomonas bacteria, sensory parameters and freshness showed significant differences in experimental and control treatments (P<0.05). The studied factors did not show significant difference in modified atmosphere treatments compared to vacuum treatments (p> 0.05). Coliform, Escherichia coli and anaerobic bacteria were not observed in experimental and control treatments. Sensory evaluation and frshness were better in modified atmosphere treatment compared to vacuum treatment (p> 0.05). Chemical, microbial, sensory factors and freshness had significantly different in the experimental treatments compared to the control sample (p<0.05). The experimental and control treatments had good quality during 14 and 6 days at refrigeration. Conclusion: Considering the absence of significant differences in microbial and chemical quality of experimental treatments and higher sensory evaluation and freshness of modified atmosphere treatment compared to other treatments, modified atmosphere packaging method is recommended for packing Tilapia fish fillet at refrigerator temperature.

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Since the process of traditional ice cream production enhances the chance of its microbial contamination, leading to a higher risk of foodborne disease in human, this study designed to determine the microbial contamination of traditional ice cream products sold in Tehran from March 2008 to March 2011.In this cross-sectional, descriptive-analytical study, the ice cream samples were collected randomly from different vendors in Tehran and transported to the laboratory of Food and Drug Deputy of Shahid Beheshti University of Medical Sciences. The samples were examined for their total mesophilic aerobic bacteria, Enterobacteriacea, Escherichia Coli, Staphylococcus aureus and mold. The laboratory examinations were conducted using the specific national standards for any organism. The descriptive data were obtained and the chi-square test, at significance level of p<0.05, was used to compare the level of contamination between different time periods. Ninety four percent of the samples did not meet the national microbiological standards for ice creams. Total mesophilic aerobic bacteria, rate of Enterobacteriaceae and mold were higher than the safety limits according to Iranian national standards in 88.1%, 100% and 73% of the samples, respectively. Escherichia Coli and Staphylococcus aureus were isolated from 23.6% and 4% of the samples, respectively. There was a significant difference between Staphylococcus aureus contamination of the ice creams in the Spring-Summer periods of 2008 to 2011. No other significant difference was shown between different time periods in this study. This study did not show any improvement in the microbial contamination of the ice creams during the study period.The high microbial load of the traditional ice creams confirms unhygienic conditions on their process of production and sale. Implementation of hygienic practices and regular control on these processes is recommended to minimize the risk of contamination.  

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The aim of present study was therefore to investigate the effect of different duty cycles (8, 12 & 16%) at different times (2.5, 5 & 10 min) of plasma treatment on anthocyanin content, color change and microboal quality of barberry juice in comparison with thermally pasteurized (80 °C for 2 min) and untreated samples. The results showed that all plasma-treated samples possessed higher anthocyanin content as well as greater L* and a* values than thermally-treated and untreated samples (p≤0.05), regardless of duty cycles and treatment times; This superiority was, however, more pronounced (p≤0.05) for the longer plasma treatments. Likewise, the longer plasma treatment was accompanied by significant decrease in total microbial count as well as yeasts and molds count (p≤0.05) of barberry juice. It was observed that the improving effect of prolonged plasma treatment on microbial quality of barberry juice was intensified at higher duty cycles. However, the microbial quality of plasma-treated barberry juice was far lower than that of thermally pasteurized sample. The results of this study show that the barberry juice treated with cold atmospheric plasma had higher nutritional value and more desirable color than thermally pasteurized one but despite the decrease in contamination, failed to meet the requirements of ISIRI for microbial quality.

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Plant essential oils and extracts are the compounds that can inhibit bacterial growth at low concentrations. Also, these materials are mostly strong antioxidants and the presence of these two properties together increases the shelf-life of fish. This study was done to investigate effect of various concentrations of caraway and thyme essences on chemical and microbial quality of common carp fillet. Different concentrations of essential oils (0, 500, 1000 and 2000 mg/l) were added to fish samples and some chemical and oxidation factors, microbial quality and sensory properties of the samples were determined. The results showed the lowest levels of total volatile basic nitrogen was related to 2000 mg/l thyme essential oil (24.6 mg/100 g fillet) and the highest amount of total volatile basic nitrogen were observed in control treatment (75.11 mg/ 100g fillet) at refrigerator temperature. TBA levels in all treatments increased with increasing storage time and at the end of the storage period, except in 500 and 1000 mg/l thyme essences treatments, there was significant difference among all experimental samples (p<0.05). The results showed that various concentrations of essences reduced the total count and Psychrotrophic bacteria compared to the control. At the end of the storage time, treatment of 2000 mg/l caraway essence, 1000 mg/l caraway essence and 2000 mg/l thyme essence had the lower Psychrotrophic bacteria than the other samples. Treatments with 1000 and 2000 mg/l caraway essences in freezing conditions received the most colors score. The highest score of texture was related to 2000 mg/l thyme essential oil at refrigerator temperature. Samples containing 1000 mg/l caraway essence in freezing temperatures had the highest odor score. In general, 1000 and 2000 mg/l concentrations of thyme essence due to acceptance of the organoleptic characteristics from the consumer view as well as reduce microbial growth and chemical factors are recommended.

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Plant essential oils can prevent the growth of bacteria and increase the shelf life of food products such as seafood and fish. In this study, the effect of zizphora and tarragon essential oils at concentrations of 500, 1000, and 2000 mg/L on microbial quality and shelf life of rainbow trout fillets stored at 4 ºC was investigated. The results showed that the essential oils of ziziphora and tarragon were effective in reducing the production of volatile nitrogen bases and the greatest effect was related to ziziphora essential oil with a concentration of 2000 mg/L. It was also observed that the use of ziziphora and tarragon essential oils reduced the total viable counts, psychrotrophic bacteria, coliforms, and Escherichia coli bacteria compared to the control sample, which confirms their antimicrobial properties. It was concluded that ziziphora essential oil with a concentration of 2000 mg/L was more effective than tarragon essential oil in controlling the microbial load and delaying the spoilage of rainbow trout fillet at refrigerator temperature.

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Milk and dairy products such as yogurt and kashk have long been used as part of the human diet and are among the most important suppliers of a large part of the human need for calcium. This study aimed to investigate the microbial quality of Rasht traditional yogurt and kashk samples. 25 samples of traditional yogurt and 25 samples of traditional liquid kashk were randomly collected from the supply centers of Rasht from December to March 2021. The microbial quality of the samples was investigated in terms of contamination with coliform, Escherichia coli, coagulase-positive staphylococci, sulfite-reducing clostridia, mold, and yeast. The contamination with coliform in traditional yogurt and kashk was 0.35 ± 0.12 and 0.11 ± 0.08 log cfu/g, and the contamination with mold and yeast in traditional yogurt and kashk was 2.07 ± 0.52 and 0.60 ± 0.18 log cfu/g, respectively. No significant difference was found between the samples of traditional yogurt and kashk in terms of contamination with E.coli, but a significant difference was between traditional yogurt and kashk samples in terms of contamination with mold and yeast and their contamination level was much higher. According to the results, the microbial quality of traditional yogurt was low. Therefore, health control of production units and monitoring of traditional yogurt production in Rasht City should be done continuously until the contamination in traditional yogurt is reduced.