نشریه بهداشت مواد غذایی
سال دوازدهم شماره 4 (پیاپی 48، زمستان 1401)

The production of imitation whey-less cheeses is one of the new achievements in the dairy industry, which has been noted for its nutritional and economic aspects. In these cheeses, it is possible to increase the nutritional value of cheese and decrease the production costs by using plant ingredients. The effect of quinoa germs was investigated on the physicochemical properties, phenol compounds, textural profile, and microbial and sensory properties of whey-less cheese. The results showed that with increasing quinoa germs, the dry matter, acidity, and fat in dry matter content increased and moisture and protein content decreased in all samples (p<0.05). The value of hardness, springiness and cohesiveness of the samples containing quinoa germs were significantly lower than the control sample (without quinoa germs). However, the samples with higher amounts of quinoa germs had the highest hardness, springiness, cohesiveness, gumminess and chewiness compared to the ones with lower values of quinoa germs (p<0.05). According to the sensory results, the flavor score was significantly improved by adding the quinoa gems up to 6%. But with the increasing germs to 9 %, the flavor score decreased significantly (p<0.05). Based on the results obtained in this study, 6% of quinoa germs can be used in the preparation of whey-less functional cheese.

The aim of this study was to investigate the effects of thyme endophytes belonging to the Lordegan region on Shigella sonnei and Candida albicans.  Thyme components were immersed in 70% ethanol (2 minutes), 3.5% sodium hypochlorite (5 minutes), and 75% ethanol (30 seconds), respectively, and lastly washed with sterile distilled water. Subsequently, they were cultured on YEA and PA medium, and the endophytes were isolated. A total of 8 bacterial endophytes were taken from different parts of the Lordegan thyme plant (stem, leaves, and roots) and examined. The endophytes isolated from thyme were bacilli, coccobacilli, and cocci. Antimicrobial and inhibitory properties of endophytes isolated from Lordegan thyme were studied in two methods structural factors and secretory metabolites of endophytes. The results of this study showed the beneficial effects of thyme endophytes on Shigella sonnei and Candida albicans. Bacterial endophytes isolated from thyme (roots stems and leaves) showed stronger inhibitory effects than the study of secretory metabolites against S. sonnei and C. albicans. In general, thyme could be a good alternative to chemical drugs in the treatment of Candida infections, especially cutaneous mucosal candidiasis, and shigellosis, and can be used in therapeutic cases, food, health, and pharmaceutical industries.

Fish and shrimp are very good sources of nutrients such as omega-3 fatty acids, vitamin D, and protein, so they form an important part of people's diet; However, seafood can bring risks for consumers, so the purpose of this study is to investigate the prevalence of Vibrio types in fish and shrimps caught in Qeshm city, Iran. In this study, 250 samples, 50 of each sample, including salted fish, Halvasfid, milkfish, shoe fish, and shrimp, were randomly taken from the beach of Qeshm City and transferred to the food hygiene laboratory of Shahrekord Azad University. The samples were tested according to the standard method of searching for Vibrio species. SPSS version 23 statistical software and chi-square statistical test were used for data analysis. The limit of significance in this study was considered (P<0.05). The results showed that the highest level of contamination among Vibrio was related to parahaemolyticus with 74% of contamination and the lowest level of contamination was related to alginolyticus with 14% of contamination. The contamination rate of salted fish, Halvasfid, milkfish, shoe fish, and shrimp were 30, 16, 6, 24, and 23% respectively. In this study, the risk of consuming raw, half-cooked, or undercooked products is clear. Therefore, it is important to pay attention to the hygiene principles after catching, i.e., freezing until the time of consumption and adequate cooking of the product.

Histamine and tyramine are biogenic amines, which are toxic compounds produced by several microorganisms as a result of the metabolism of some amino acids and the decarboxylation reaction during fermentation or food spoilage. This study aimed to investigate the content of histamine and tyramine in cheeses distributed in Qazvin. Sixty samples including 30 samples of Koozeh cheese, 15 samples of pasteurized cheese, and 15 samples of probiotic cheese were collected randomly from September to December 2021 from Qazvin. The content rates of histamine and tyramine in the samples were determined by high-performance liquid chromatography. All cheese samples contained histamine and the samples of Koozeh, pasteurized and probiotic cheeses contained 100%, 100% and 6.66% of histamine, respectively which are higher than the permissible limit (100 mg/kg). The mean value of histamine in the samples of Koozeh, pasteurized and probiotic cheeses were 208.37±34.94, 123.80 ± 12.04, and 66.67 ± 18.27 mg/kg, respectively (p<0.05). The values of tyramine in all the samples were within the permissible limit (600 mg/kg) and the mean values of tyramine in the samples of Koozeh, pasteurized and probiotic cheeses were 145.85 ± 15.24, 77.49 ± 10.34, and 45.98 ± 9.31 mg/kg, respectively(p<0.05). According to the results, it seems that the use of Koozeh and pasteurized cheeses in Qazvin is not suitable for people who are sensitive to high levels of histamine, and it is recommended that this group of people use probiotic cheese.

polyunsaturated fatty acids, and pH. One of the methods which can control the spoilage rate is the use of natural coatings. This study aimed to investigate the effect of coating Tilapia fish fillets with whey protein concentrate (10, 15, and 20% w/w), maltodextrin (15, 20, and 25% w/w), and rosemary essential oil (1, 3 and 5% v/w). The optimization of the process was conducted by response surface methodology and Design Expert software. For this purpose, 18 models were presented by the software, and the samples were immersed in the produced solutions and were kept at 4 °C for 6 days. After this period, peroxide value (PV), Thiobarbituric acid (TBARS), Total Volatile Basic Nitrogen (TVBN), and pH were measured. The results showed that by increasing the concentration of biopolymers and essential oil, all the investigated parameters were in lower limits, and in the sample coated with the maximum concentration of substances, the values of PV, TBARS acid, TVBN, and pH (in 100 grams), were 1.05 meq, 0.05 mg, 5.7 mg and 6.2, respectively, while these values for the coated sample with minimum concentrations, were 3.44 meq, 0.305 mg, 10.85 mg and 6.79 respectively. By optimizing the production process by software, the best solution was achieved by mixing 11.214% w/w of whey protein concentrate, 25% w/w of maltodextrin, and 3.402% v/w of rosemary essential oil.

Essential oils and extracts of medicinal plants have been highly regarded as natural food additives and preservatives due to the presence of bioactive compounds and functional activities, including antioxidant and antimicrobial properties. In this research, Hypericum perforatum and Oliveria decumbens were extracted by the maceration method and ultrasonic waves. Total phenolic compounds, and antioxidant as well as antimicrobial activities were assessed by GC-MS. Minimum inhibitory and minimum bactericidal concentrations against Escherichia coli, Staphylococcus aureus, and Aspergillus niger were evaluated. The results showed that 19 main compounds, the most important of which are Thymol (24.40%), Carvacrol (23.00%), and Myristicin (9.78%), comprise 90.22% of O. decumbens extract. In the extract of H. perforatum, 20 compounds constitute 94.16% of the extract, among which Hypericin (25.92%) and Hyperforin (16.69%) are the most important effective compounds. The content of phenolic compounds of Hypericum perforatum and O. decumbens extracts were 24.0 and 9.5 mg/g of dry weight, respectively. H. perforatum extract shows higher antioxidant activity compared to O. decumbens extract (IC50 of H. perforatum and O. decumbens extracts are 0.173 and 0.470 g/ml, respectively). The extract of H. perforatum inhibited the activity of S. aureus and E. coli, however, did not significantly inhibit the activity of A. niger.