JOURNAL OF APPLIED MICROBIOLOGY IN FOOD INDUSTRY
Year:2019 | Volume:5 | Issue:2|Papers Count:6

In this study, for the first time, the pattern of changes in inhibition zone diameter was assessed by three differential models, i. e., J shape, S shape and semicircular shape. To prove the generalizability of these modeling techniques, the change of inhibition zone diameter of Avicennia marina extract (obtained by different procedures, i. e., ethanol, ethanol-ultrasound, aqueous, aqueous-ultrasound), at eight different levels (5, 10, 15, 20, 25, 30, 35 and 40 mg/ml) against Escherichia coli and Listeria innocua was investigated. Results showed that, all models were capable of modeling the inhibition zone diameter, while, semicircular shape model was the best in investigation of inhibition zone diameter against Listeria innocua (R2=0. 89-0. 94, R2adj=0. 87-0. 93, cross R2adj=0. 80-0. 85 and RMSE=0. 96-1. 45), as well, S shape model was the best in assessment of inhibition zone diameter against Escherichia coli (R2=0. 90-0. 95, R2adj=0. 88-0. 93, cross R2adj=0. 82-0. 87 and RMSE=0. 25-0. 42). Furthermore, results showed that different extracts of Avicennia marina imparted a greater effect on Listeria innocua than Escherichia coli. It's worth mentioning that, the novel differential models with important biological parameters are able to provide better insight into biological systems.

Post-harvest diseases are one of the most common causes of damage to fruits and vegetables, and the use chemical fungicides is the fastest method to control it. Therefore, in this study, it was investigated the effect of Neem, Thyme, fennel and Zataria extracts on apple blue mold, as an alternative to chemical fungicides. In this study, it was studied the effect of the plant extracts in vitro on the growth of fungal pathogen apple blue mold (P. expansum) by two methods included the paper disks and mixed media culture. Then, the effect of some plant extracts of Thyme and Fennel was studied on the rate of symptoms in a cold storage (4 ̊ C). The results showed that the aqueous and alcoholic extracts of thyme with a concentration of 500 ppm and with 24. 79 and 26. 65 mm diameter inhibition zone of pathogen, respectively, were the best extract. The results of another in vitro test, the mixing test of plant extracts with the culture medium, were exactly the same as the disk test, and the concentration of 2000 ppm of aqueous and alcoholic extracts of thyme was 62. 49 and 72. 66, respectively, it reduced the pathogen growth when it was compared to the control. The results of the storage test showed that the area of spot formed in the treatment of aqueous and alcoholic extracts of thyme with a concentration of six in 1000 was 70. 52 and 85. 69% in comparison with the control, in other words, this concentration of thyme aqueous extracts showed the highest control of the disease in the storage. Based on the findings of this study, Thyme and Zataria extracts had the potential to control plant diseases, especially post-harvest diseases.

Medicinal herbs contain large secondary compounds that often have important biological activity, and since extracts of plants are widely used in the pharmaceutical, food, and health industries, various extraction methods are very important. One of these herbs is the olive leaf, which has more beneficial properties than other parts due to its phenolic compounds, its antioxidant and antimicrobial effects. The purpose of this study was to determine the optimal conditions for extraction of bioactive compounds in the olive leaf of Minoodasht area of Golestan province, using by subcritical water method and its antibacterial effect on Staphylococcus aureus and Escherichia coli bacteria by the methods of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) and Disc Distribution. Optimum extraction conditions were carried out at temperatures 120-180 ° C, under a pressure corresponding to the extraction temperature and mixing ratio of 1: 20, with physicochemical properties (efficiency, turbidity, and brix). Antimicrobial properties (MIC and MBC) of extracts extracted by each and every one (soaking and subcritical water) against Staphylococcus aureus and Escherichia coli bacteria in concentrations of 25-5130 ppm with three replications, the results showed that the effect of high concentrations of bioactive compounds in extracts obtained by the subcritical water method on gram-positive bacteria of Staphylococcus aureus. Also, in the disk diffusion method, resistant gram-negative bacteria of Escherichia coli and Staphylococcus aureus was the most sensitive bacteria.

The use of probiotic supplements in the beekeeping industry can increase the growth rate and improve the feed conversion ratio and improve resistance to the disease and increase the production of honey. In this study, probiotics of two species of Lactobacillus vermiform and Lactobacillus fermentum isolated from honey bee stomach, under the diagnostic tests. The mentioned probiotic bacteria in quantities 108 cfu/ml as individually and mixed inoculated into natural peach and strawberries juice. The product tests included acidity acidity and pH assessment, soluble solids content (Brix), viability assessment of probiotic bacteria, evaluation of sugary regeneration, as well as sensory evaluation. The results showed that increasing the duration of maintenance and increasing the probiotic population increased acidity, pH, brix and also the percentage of reducing sugars significantly (p≤ 0. 05) deacreased. Also sensory properties of the treatments were significantly associated with decreasing acceptability during storage and also increasing the probiotic population (p≤ 0. 05). Over time, survival of probiotics was reduced in all treatments that the least reduction was observed in treatments contain mixing of two types of probiotics. Althought the number of probiotic bacteria during 21 days decreased but their number after 21 days of storage was higher than 106 cfu/ ml, so they were considered as probiotics in accordance with national standard for jouices. The results showed that the tratment contains peach juice with a population of 108 cfu/ml from the 50% mixture of Lactobacillus vermiform and Lactobacillus fermentum was selected as the optimal treatment.

Secondary metabolites with bioactive and functional properties in essential oils of plants can be effective in improving the quality and shelf life of most foods as natural preservatives. On the basis RSM, Essences from Thymus, Satureja and Dianthus in three levels 300, 600 and 900 ppm were added to 2cm cube beef and coated by 4% modified starch suspention. The effective levels of these components to prevent microbial growth, fat oxidation and texture deterioration were evaluated. Results and Discussion: Results showed that Dianthus in 900 ppm level had the highest effect in preventing total count increase while thymus was the most effective essence against the psychrophilic bacteria. The mixture of Thymus, Satureja and Dianthus in 900ppm was the most effective on the peroxide value. The combination of 500ppm Dianthus and 600ppm Saturia was the most effective item to keep the meat firmness during the storage. Optimizing the parameter levels showed that Thymus in 703. 019ppm, Dianthus in 900ppm and Saturia in 482. 17ppm mixture can meet 87% of our expectations. In this study, using 4% hydroxyl propylene starch suspensions, essential oils of Thymus, Satureja, Dianthus are used while maintaining the quality of the product and increasing the length of the meat storage period. The purpose of this study was to determine the effective concentration of these compounds in preventing the growth of microorganisms and fat oxidation. The results of the experiments showed that for 15 days of microbial tests, such as Total Kant, Staphylococcus aureus, Hemostatus, for the physical test of hardness and adhesion, and for the chemical test of peroxide number, the equation was obtained according to the test response, Which well describes the relationship between the concentration of essential oils of Thymus, Satureja, Dianthus and the test. At the end the optimal conditions were determined.

In the poultry industry, additives such as antibiotics are used to increase performance and reduce mortality. In recent years, probiotics are used in poultry nutrition due to their beneficial effects on production and absence in carcasses. In the poultry industry, Bacillus spp. probiotics are used to help increase feed intake and reduce the risk of salmonella infection. The purpose of this study was to isolate native probiotic strains with these abilities. In this research, 25 samples from freshly feces from 7 poultry and 16 samples from 3 rice field regions of Golestan province were collected. After isolation of Bacillus spp. on nutrient agar, their probiotic characteristics such as enzyme production, bile salt, acid, pepsin, trypsin and antibiotic resistance, and the ability of attachment to intestinal epithelial cells and inhibit Salmonella enterica serovar Typhimurium invasion were evaluated. The selected strain was identified by polymerase chain reaction (PCR) and 16S rDNA sequence. Top strain was identified as Bacillus tequilensis, which showed the highest binding to epithelial cells of the intestine and prevented the binding of Salmonella spp. This strain can improve the quality of poultry as a chicken diet and reduce the incidence of salmonellosis in chickens and humans, which, if this is achieved, will be a step towards consumer health. Considering the results obtained in this project, it is hoped to produce native probiotic for the prevention of Salmonella infection in Iran.