Journal of Food Microbiology: 4 (3)

Open Access Article

1 - Identification of some of the biofilm forming bacteria from the pasteurized milk production line
Sayedeh Saleheh Vaezi Arezoo Tahmoures Mohammad Goli

Biofilm is a collection of microorganisms in an extracellular exopolysaccharide matrix (EPS) which is adhered to the surface. Biofilms are considered as the most important food industry`s problem, especially in the post-contamination of pasteurized products. It is due t More

Biofilm is a collection of microorganisms in an extracellular exopolysaccharide matrix (EPS) which is adhered to the surface. Biofilms are considered as the most important food industry`s problem, especially in the post-contamination of pasteurized products. It is due to the high resistance feature of biofilm to the antimicrobial factors and Cleaning in Place (CIP) process. In this study, the bacterial biofilm from the inner part of pasteurized milk production line were isolated and bacterial compositions were assessed in order to identification of effective agents of post-contamination of pasteurized products. In order to conduct this survey, after CIP process, sampling was done from ten different parts of the production line (in 3 replicates). Isolation, purification and probable identification of isolated bacteria according to Bergey’s Manual of systematic bacteriology were performed. Results showed the presence of bacteria from different genera of Listeria, Shigella, Staphylococcus, Pseudomonas, Escherichia, Corynebacterium, Bacillus, Aeromonas. Klebsiella, Proteus, Lactobacillus and Micrococcus in which Staphylococcus and Shigella sonnei were the most predominant isolated genus and specie with 19% and 11% of the whole population, respectively. Manuscript profile

Open Access Article

2 - The antimicrobial effects of Mentha longifolia L. essential oil on Salmonella enteritidis in mayonnaise sauce
shaghayegh Ghorbani Leila Rouzbeh-nasiraei Mohammad Hassan Juri

Now adays, there is a considerable tendency to use herbal essential oil as natural preservatives in foods and nutrition. Studies of their antimicrobial impact in the food models to achieve a safe and healthy food is growing. Mentha longifolia plant of the Laminacea fami More

Now adays, there is a considerable tendency to use herbal essential oil as natural preservatives in foods and nutrition. Studies of their antimicrobial impact in the food models to achieve a safe and healthy food is growing. Mentha longifolia plant of the Laminacea family has antimicrobial compounds, Carvacrol and Thymol which are found in the essential oil of this plant. The aim of this study is to survey and evaluate the antimicrobial activity of essential oils of Mentha longifolia and the possibility of its application as a natural preservative and flavor in mayonnaise. In this study, the antimicrobial effect of different concentrations (1250, 2500, 5000 and 10000 ppm) Mentha longifolia essential oil on Salmonella enteritidis in mayonnaise at 4 and 25 °C were evaluated in 30 days. Factorial experiments in a completely randomized design, with three repetitions were analyzed by SPSS software. The results showed that the antimicrobial effect of “essential oil of oregano” at 25 °C is higher than 4 °C (p<0.05) and this effect increased by increasing the density of oil in the samples. The greatest impact of the essential oil concentration was 10000 ppm at both temperatures. While the increase in essential oil concentration in the samples, the sensory acceptability of food was reduced considerably. According to the results of sensory evaluation and microbial tests, the concentration of 1250 ppm oil in mayonnaise samples, have favorable results in reducing the number of bacteria up to 6 logarithms and gain a sensory of acceptance. Manuscript profile

Open Access Article

3 - Evaluation of antimicrobial activity of Lactobacilli isolated from traditional sourdoughs against Bacillus cereus
Abolfazl Golshan Tafti Ghazal Yazdanpanah Mohammad Hassan Fooladi

In this study, the inhibitory effect of 71 Lactobacilli isolated from traditional sourdoughs against Bacillus cereus was evaluated and compared by using three methods (spot on lawn,well diffusion and disk diffusion). There was no inhibition zone around the discs and wel More

In this study, the inhibitory effect of 71 Lactobacilli isolated from traditional sourdoughs against Bacillus cereus was evaluated and compared by using three methods (spot on lawn,well diffusion and disk diffusion). There was no inhibition zone around the discs and wells in the well diffusion and disk diffusion methods. The inhibitory effect of Lactobacillus isolates against Bacillus cereus in the Spot on lawn method was observed as a clear zone around the colonies. All Lactobacillus isolates were able to inhibit the growth of Bacillus cereus in the spot on lawn method, but there was a significant difference (p<0.01) among the isolates in terms of antimicrobial activity. Among the Lactobacillus isolates, 8 isolates had significantly stronger antimicrobial activity and the diameter of clear zone around the colonies was reported in the range of 2.67-7.83 mm. The diameter of clear zone around the Lactobacillusisolates 70, 46, 21, 55, 59 and 11 was 7.83, 7.67, 7.33, 7.16, 7 and 7 mm, respectively. Therefore, they were reported as Lactobacillus isolates with strong antimicrobial activity in the spot on lawn method. These isolates can have potential to be used as starter cultures in production of sourdough and bread. Manuscript profile

Open Access Article

4 - Editorial Board

Manuscript profile

Open Access Article

5 - Study on antibacterial effect of rosemary extract in combination with nisin against staphylococcus aureus in minced meat during refrigerated temperature
Zhila Ghasemi Peyman Mahasti سکینه نوری سعیدلو

Synthetic preservatives have been used as food additives to extend shelf life of foods, but they are strictly regulated due to toxicological concerns and some health problems. So it is increasingly attractive to find out effective and nontoxic measures (e.g. use of natu More

Synthetic preservatives have been used as food additives to extend shelf life of foods, but they are strictly regulated due to toxicological concerns and some health problems. So it is increasingly attractive to find out effective and nontoxic measures (e.g. use of natural antimicrobial agent) to delay microbial spoilage. Nisin is a bacteriocin that it is the only bacteriocin permitted for use in foods. And rosemary is one of the medicinal plants. In this study the effect of antibacterial property of various concentration of rosemary extract alone (3 and 4 mg/ml), and with nisin (7 µg/ml nisin + 1.5 mg/ml RE and 8 µg/ml nisin + 2 mg/ml RE) against Staphylococcus aureus in minced meat were assessed throughout 14 days of storage at 4±1˚C. Leaves and stems of rosemary after drying in the shade were soaking in pure ethanol and alcoholic extract was obtained. The minimum inhibitory concentration (MIC) of RE and nisin were determined against S. aureus using the agar dilution method. Assessment of microbial parameters (total plate count and S. aureus count) was carried out in 0, 1, 3, 7 and 14 days. The data were statistically significant (P<0.05). The results reveals that treatment with both concentrations of RE showed significantly lower microbial indexes in comparison with controls, but treatment with both preservative (nisin & RE) had better results and results were statistically significant (P<0.05). As a consequence, using of RE with nisin was better than of RE alone. Manuscript profile

Open Access Article

6 - Table of contents

Manuscript profile

Open Access Article

7 - Isolation and Identification of Pediococcus Species from Raw Milk of Iranian One Humped Camel and Evaluation of Their Antibacterial Properties
Nafiseh Davati Farideh Tabatabaei yazdi Saeed Zibaei

Iran is a country with vast arid desert and camels have many adaptations that allow them to live successfully in desert conditions. Lactic Acid Bacteria such as Pediococcus play an important role in quality of fermented products of camel milk. A total of three samples o More

Iran is a country with vast arid desert and camels have many adaptations that allow them to live successfully in desert conditions. Lactic Acid Bacteria such as Pediococcus play an important role in quality of fermented products of camel milk. A total of three samples of raw milk of Iranian one humped camel (Camelus dromedarius) were collected from Golestan province in Iran under aseptic conditions. Among isolated bacteria, only six isolates were phenotypically characterized as pediococcus species. Six bacterial isolates were identified by amplification of the 16S rRNA gene by Polymerase Chain Reaction (PCR) and were then grouped by the Amplified Ribosomal DNA Restriction Analysis (ARDRA) method. Based on restriction analysis of 16S rRNA gene, the isolates of pediococcusgenus were grouped into one ARDRA pattern that were identified by ribosomal DNA sequencing as Pediococcus pentosaceus. The antimicrobial activity of Pediococcusisolatesagainst Salmonella typhi PTCC 1609 and Bacillus cereus ATCC 10876 was examined by the Spot on lawn method. The results showed that antimicrobial activity of P. pentosaceus isolated from raw milk of Iranian camel was remarkable was remarkable.  Manuscript profile

Open Access Article

8 - A Study on the Synergistic Effect of Sunflower Oil Based Nanoemulsion with Zataria multiflora Boiss. Essential Oil on the Quality of Rainbow Trout Fillets
Shabnam Shadman Sayyed Ebrahim Hosseini Hadi Ershad Langroudi Shahrokh Shabani

The quality changes of farmed rainbow trout (Oncorhynchus mykiss) fillets treated withsunflower oil based nanoemulsion with or without Zataria multiflora Boiss. essential oil was studied on days 0, 5, 10 and 15 during storage in (4oC±1) and evaluated by microbiol More

The quality changes of farmed rainbow trout (Oncorhynchus mykiss) fillets treated withsunflower oil based nanoemulsion with or without Zataria multiflora Boiss. essential oil was studied on days 0, 5, 10 and 15 during storage in (4oC±1) and evaluated by microbiological and sensory analyses. Total viable counts and psychrophilic bacteria were determined. The results showed that the nanoemulsion had significant effect (P<0.05) on total viable counts. No growth of psychrophilic bacteria was found. Sensory analysis showed that the nanoemulsion could improve colour features. Odour and texture were enhanced as well. Incorporation of Z. multiflora essential oil and the nanoemulsion increased the acceptability for taste, odoure and texture. The inhibitory effects of the nanoemulsion were closely related to the concentration of the essential oil due to high content of carvacrol and thymol. The quality of fillets treated with nanoemulsion and 1% Z. multiflora essential oil was significantly different compared with other treatments and had acceptable results until day 15 of storage. Therefore, the nanoemulsion developed in this study could be represented as an option as a food preservative. Z. multiflora Boiss. essential oil showed a synergistic effect with the nanoemulsion for shelf-life extension of rainbow trout fillets.  Manuscript profile

Open Access Article

9 - Designing predictive model for microbial load in sausage meat processing with using impedance method and survey on its correlation with reference
Reyhaneh Sororyan Laleh Roomiani Ali Fazlara

The objective of the present study was to employ the technique of Impedance Splitting Method, a technique of high accuracy and sensitivity, in the microbial count and characterization based on their rate of metabolic activity leading to a change in electrical resistance More

The objective of the present study was to employ the technique of Impedance Splitting Method, a technique of high accuracy and sensitivity, in the microbial count and characterization based on their rate of metabolic activity leading to a change in electrical resistance in the shortest possible time. A total bacterial count on samples (n= 80 of sausage) collected during the cold and warm seasons, were evaluated by the standard and the Impedance splitting methods (ISM). Based on the obtained coefficient of determination results in the resulting mathematical equations, the correlation coefficient between the two methods in relation to the total bacterial count in sausage, in the summer and winter seasons, as well as the cumulative results have been 93.9, 93.1and 95%, respectively. This study suggests that impediometric technique can be used as a rapid and reliable method to accurate estimation of sausage bacterial loads. This initial evaluation of the suitability of indirect impedance to generate microbial growth data in complex food matrices indicates significant potential for the technology as an alternative to plating methods. Manuscript profile

Open Access Article

10 - Prevalence rate and presence of virulence genes of Escherichia coli O157: H7 in raw milk and traditional cheese at Marand retails
Asgar Nagezadeh Hamid Mirzaei

The aim of this study was to estimate the prevalence rate of Escherichia coli O157: H7 in raw milk and traditional cheese at Marand retails. Moreover, the isolates were assessed for the presence of virulence gene of stx1, stx2, eaeA and hly. For this reason, 100 traditi More

The aim of this study was to estimate the prevalence rate of Escherichia coli O157: H7 in raw milk and traditional cheese at Marand retails. Moreover, the isolates were assessed for the presence of virulence gene of stx1, stx2, eaeA and hly. For this reason, 100 traditional cheese and 50 raw milk samples were collected randomly. The samples were enriched in EC broth containing novobiocin and were isolated on sorbitol MacConkey agar with cefixime and tellurite. The isolates were further assayed by VRBA, tryptone broth and Escherichia coli Chromogenic agar for the lactose fermentation, indole production and beta-glucuronidase activity, respectively. The selected colonies were confirmed by E. coli O157: H7 antiserum and finally the isolates were analyzed for the presence of virulence genes. According to the results, 9% (9/100) of cheese and 10% (5/50) of raw milk samples were found contaminated with sorbitol-negative E. coli. Using the anti-E. coli antiserum, 1 isolate (2%) among the milk samples was confirmed and the presence of virulence genes of eaeA and stx1 were determined by multiplex PCR. With respect to the occurrence of E. coli O157: H7 in raw milk and its high persistence to acidic environment, it was concluded that raw milks and traditional cheeses marketed at Marand could be considered as the potential source of infection to humans. Manuscript profile

Open Access Article

11 - Detection of zoonotic Lactococcus garvieae in rainbow trout meat and evaluation of virulence gene
Mehdi Raissy mahsa Ansari

Lactococcosis which is caused by Lactococcus garvieae is now widespread. This species is categorized in zoonosis agents and is able to cause endocarditis especially in immunosuppressed persons. This study was done to detect Lactococcus garvieae in cultured rainbow trout More

Lactococcosis which is caused by Lactococcus garvieae is now widespread. This species is categorized in zoonosis agents and is able to cause endocarditis especially in immunosuppressed persons. This study was done to detect Lactococcus garvieae in cultured rainbow trout meat collected from retail market and to evaluate the virulence of the isolates. A total of 90 fresh fish were randomly selected and were transferred to the laboratory in appropriate conditions. After collecting meat samples, the bacteria were investigated by culture on BHIA and standard biochemical tests. The results were confirmed by PCR. Presence of virulence gene in the isolates were studied and the results revealed that 4 isolates of a total of 9 collected isolates harbored cap virulence gene (44.4%). According to the results, rainbow trout meat can be contaminated with Lactococcus garvieae which is a potential danger for consumers. However, it depends on the nutritional habits and methods of reservation. Manuscript profile

XML

List of Articles