نشریه بهداشت مواد غذایی
سال دوازدهم شماره 3 (پیاپی 47، پاییز 1401)

As a byproduct of the milling process, wheat germ provides a rich source of minerals, vitamins, tocopherols, phytosterols, amino acids, and important fatty acids. However, the high levels of unsaturated oil and high levels of enzymes lead to a reduction in wheat germ's nutritional value during storage, which severely reduces the product's shelf life. The purpose of this study was to use guar gum and maltodextrin together with the freeze-drying encapsulation technique to extend the shelf life of probiotic wheat germ containing Bacillus licheniformis. In this regard, the durability of the encapsulated probiotic wheat germ was assessed for 360 days of storage using three different ratios of maltodextrin to guar gum, including 1 to 0.3, 0.1, and 0.03. The tests were carried out using a completely random design, and the averages were assessed using Duncan's test with a significance level of 5%. The effect of time on the changes in oxidation indices of the encapsulated wheat germ was evaluated positively. During 360 days of storage, the encapsulated sample with maltodextrin and guar gum in all examined ratios significantly reduced the total acid value (P< 0.05). In comparison to samples without probiotics, the inclusion of B. licheniformis probiotic considerably reduced the values of the total acid number and TBA index (P< 0.05). In the probiotic treatment, the levels of peroxide, anisidine, totox, mold, and yeast significantly increased with longer storage times (P< 0.05).

Nowadays, chemical food contaminants are considered among the serious health concerns in various countries. Arsenic and mercury are the most important heavy metals which cause different complications in humans. The present study aimed to determine the dietary intake of mercury and Arsenic using total diet study (TDS) method in the adult population of 20-50 years old in Shiraz. Total of 580 food items were prepared and classified into 129 composite samples. After preparation, the samples were digested. The concentration of mercury and Arsenic were measured using inductively coupled plasma–optical emission spectrometry (ICP-OES). The dietary intake of Arsenic and mercury was calculated based on the mean food intake. Fish had the highest concentration of Arsenic, and the snack samples contained the highest concentration of mercury. But it was found that the heavy metal intake is more affected by the quantity of the food consumed. Therefore, the highest contributor to dietary intake of Arsenic was drinking water and fruit, and the highest contributor to dietary intake of Arsenic was related to raw vegetables and dairy products. However, the mean daily intake of mercury and Arsenic was 0.2-8.65 µg/d and 6.5-81.81 µg/d, respectively, which is lower than the provisional tolerable weekly intakes (PTWI). Therefore, there is no health risk due to Mercury and Arsenic investigated in this research for the total diet in adult population in Shiraz.

Cheese isamong ther dairy products and is a suitable environment for the growth and reproduction of microorganisms. One of these pathogens, Neospora caninum, causes abortion in cows. This study aimed to investigate the prevalence of N. caninum in traditional cheeses produced from ruminant milk using molecular method. In this study, 86 traditional cheese samples consisting 42 cow cheese, 20 sheep cheese, 12 goat cheese, and 12 sheep cheese ripened in brine were randomly collected from dairy herds in Chahar Mahal and Bakhtiari provinces. The samples were transferred to the laboratory in sterile conditions next to ice an, and Nested-PCR technique was used on Nc5 gene for molecular analysis. The results showed that 9.3% (8/86) of the samples were contaminated with N. caninum. The highest contamination (12.5%) was found in cow milk cheese samples. No contamination was observed in traditional cheeses produced from goat milk or sheep brined cheese. The comparison of contamination levels in different cheeses showed no significant difference between the groups. Since milk and dairy products have a high place in the human food basket; therefore, the healthiness of these foods is crucial.

One of the most widely used cheeses in Iran is UF white cheese. The presence of nutrients in different types of cheese, make that susceptible to the growth of various microorganisms. Therefore, the use of preservatives to maintain the quality of this high-consumption dairy product is inevitable. In this study, the effect of concentrations of 0.3 and 0.5% aqueous and methanolic extracts of Spirulina platensis on growth inhibition of Listeria monocytogenes, Staphylococcus aureus and Escherichia coli and also the effect of these extracts in preventing the growth of A.flavus in the UF white cheese has been investigated during 60 days of storage of the product in the refrigerator. In addition, the effect of extracts on texture, taste, color and overall acceptance of the product was evaluated. According to the results, a significant inhibitory effect (p≤0.05) of concentrations of 0.3 and 0.5 aqueous and methanolic extracts was observed on Listeria monocytogenes and Escherichia coli from the 15th day of the storage period and on Staphylococcus aureus from the 30th day of the storage period. The antibacterial effect of 0.5 concentration of methanolic extract was significantly higher than other treatments (p≤0.05). All treatments had a significant antifungal effect on Aspergillus flavus strains (p≤0.05). According to the results of the present research, the used extracts did not have a significant adverse effect on the sensory characteristics of the cheese samples, although the concentration of 0.5 methanolic extract insignificantly decreased the quality of the sensory characteristics of the cheese samples. In general, it can be said that concentrations of 0.5 aqueous extract and 0.3 concentration of methanolic extract of Spirulina platensis can be used as natural preservatives in UF white cheese.

Considering the possible adverse effects on the sensory properties of food due to the use of essential oils in effective concentrations for antimicrobial and antioxidant activity, the use of combined methods can be effective. In this study, the effect of coating combination of gelatin and Opopanax mucilage containing 0.5% zinc oxide nanoparticles, enriched by concentrations of 0, 1.2, 1.6, and 2.0 % of peppermint essential oil and modified atmospheric packaging (MAP) on preventing the growth of microbial population rainbow trout fillets were evaluated during 20 days of storage in the refrigerator. The results showed that in all treatments the number of aerobic mesophilic bacteria, psychrotrophs, lactic acid bacteria, and coliforms as well as pH increased during the storage period but decreased by increasing peppermint essential oil (p<0.05). Also, the microbial load in treatments with a coating containing nanoparticles and MAP was significantly lower than in the control sample (p<0.05). The results of sensory evaluation also showed that the odor and color scores of the samples decreased during storage, which was the highest in the control and the lowest in the NPEO3 treatment (p<0.05). The results of the sensory evaluation were consistent with the results of microbial analysis. According to the results obtained in this study, using the mixture of 0.5 % zinc oxide nanoparticles and 50% peppermint essential oil in edible coating composed of Opopanax mucilage and gelatin for increasing the shelf life of rainbow trout fillet up to the 15th day is recommended.

Eggs are highly perishable due to high moisture content and nutrients. This study aimed to investigate the effect of coating with black seed oil and rosemary extract on egg physical, chemical, functional and microbial characteristics. For this purpose, 300 eggs consisted of control group, eggs coated with black seed oil, and samples coated with black seed oil and 1, 2, and 3% rosemary extract were prepared. Throughout the six weeks of storage at 4 °C, thickness, weight loss, Haugh unit, yolk index, pH, amount of egg white foam production and microbial features were investigated. The weight loss in the control group was 6.64 and 4.80 g in the control group and the treatment with 3% rosemary extract, respectively. In the control group, Haugh unit was decreased from about 75 on the first day to 31.38 after six weeks storage. Haugh unit in the egg group coated with 3% rosemary extract was 41.76. The microbial load of shell after six weeks of storage in the control sample was 4.59 log CFU/g, and in the samples coated with black seed oil alone and in the presence of 1%, 2% and 3% rosemary extract were 4.32 and 3.99, 3.27, 2.30 log CFU/g, respectively. Due to the bactericidal effect of coating components, egg-shell microbial load was decreased. The coating was able to increase the shelf life up to six weeks.