فهرست مطالب mohammad bagher habibi-najafi

Cronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. In this study, the effect of a Lactiplantibacillus plantarum strain (M17) along with the standard strain Lactobacillus plantarum (ATCC 8014) and the well-characterized probiotic strain Lactobacillus rhamnosus GG on the adhesion of C. sakazakii to intestinal epithelial cells was analyzed.

Acid and bile tolerance of M17 was evaluated in the presence of pepsin and pancreatin. L-arginine hydrolysis was investigated using an arginine-including medium. Auto-aggregation and co-aggregation assays were performed by absorbance measurement. Minimum inhibitory concentrations of the antimicrobials recommended by the European Food Safety Authority were established. Total lactic acid and the ratio of D/L lactate isomers were determined with a Megazyme enzymatic kit. The ability of the isolate to produce biogenic amines was tested by qualitative and quantitative monitoring. Hemolysis was assessed phenotypically on MRS agar enriched with sheep blood. The strain was tested for its capability to adhere to mucin and Caco-2 cells. The antagonistic effects of the strain against C. sakazakii were further evaluated in vitro on mucin and cultured Caco-2 cells. The LAB strain was added simultaneously with, before, and after C. sakazakii to Caco-2 cells for competition, exclusion and displacement assays, respectively. Data analysis was performed in R using one-way analysis of variance, and the experimental groups were compared with the controls using Tukey’s test. P values <0.05 were considered statistically significant.

There was no significant difference in the survival rate of M17 and L. plantarum ATCC 8014 at pH = 4. After 2 h of incubation at pH = 2.5, the survival rate of L. plantarum ATCC 8014 was estimated to be higher than strain M17, but this difference was not significant. After 4 hours of incubation at pH = 8, M17 showed a higher survival rate than L. plantarum ATCC 8014, and this difference was significant after transfer from pH = 4. These results confirm the appropriate viability of M17 in the gastrointestinal tract. Both M17 and L. plantarum ATCC 8014 developed the color yellow in the L-arginine hydrolysis assay, which confirms the safety of these strains. The percentage of auto-aggregation for M17, L. plantarum ATCC 8014, and Lactobacillus rhamnosus LGG was estimated at 24.38, 25.28, and 32 after 6 hours, respectively, and no statistically significant difference between the two isolates were noticed. Given the auto-aggregation and co-aggregation parameters of M17, this strain may constitute a defense mechanism against C. sakazakii. Strain M17 showed resistance to kanamycin and clindamycin antibiotics. With intrinsic resistance, the risk of transferring resistance genes is not only speculative, but practically impossible. Intrinsic resistance of lactic acid bacteria may be considered desirable because it ensures their survival when the host is treated with antibiotics. Both D and L isomers of lactic acid were produced by the studied strains. In humans, D(-)-lactic acidosis is a rare metabolic complication that has only been reported in individuals with short bowel syndrome). Clinical studies have shown that the consumption of probiotic bacteria producing D(-)-lactic acid is safe for children and does not cause a long-term increase in blood D(-)-lactic acid. The reference L. plantarum strain and M17 did not produce biogenic amine precursors, and had no ß-hemolytic activity. Mucin adhesion assay exhibited that M17 has less adhesion (12.10 ± 1.14 %) than L. plantarum ATCC 8014 (13.33 ± 2.30 %) and LGG (15.93 ± 2.06 %) although these differences were not statistically significant. However, the amount of adhesion for the positive control sample Escherichia coli K12 (25.19 ± 4.40 %) was significantly higher than those of the other strains. Compared to the positive control, M17 had a significantly lower adhesion rate (6.8 ± 1.41) to CaCo-2 cells. This value was estimated at 13.77 ± 3.53 % for the reference strain and 21.6 ± 7.54 % for Lactobacillus fermentum PCC (positive control). In antagonistic assays, M17 was able to reduce the adhesion of C. sakazakii to mucin and CaCo-2 cells in all three methods of exclusion/inhibition, competition and displacement. Statistical analysis of the results does not show a significant difference between M17 and LGG. Therefore, the performance of M17 is similar to that of the standard probiotic LGG.

Lactic acid bacteria with acceptable ability to adhere to epithelial cells can be suitable for colonization in the intestine. They can act as a barrier to fight pathogens through various competitive mechanisms, such as co-aggregation with pathogens and adhesion. The M17 strain has an acceptable immune profile and probiotic properties because it shows an acceptable antagonistic activity against C. sakazakii invasion.

Milk proteins are precursors of several biologically active peptides. One of the methods of producing these peptides is fermentation using lactic acid bacteria. The aim of this study was to investigate production of antioxidant and angiotensin-I converting enzyme inhibitory bioactive peptides in cow milk fermented by two strains of Levilactobacillus brevis.

Two strains of Levilactobacillus brevis KX572376 (M2) and Levilactobacillus brevis KX572382 (M8) were used in fermentation of low-fat cow milk. Moreover, pH changes, proteolytic activity, water-soluble extract biological activity (antioxidant activity and angiotensin-I converting enzyme inhibition) of the samples and peptide fraction less than 3 kDa were investigated at 24 and 48 h of fermentation (30 °C). Peptide profile of the superior sample was analyzed as well. Statistical analysis was carried out using one-way of variance, Tukey test and SPSS software v.25.

The two strains decreased milk pH to a similar level in the first 24 h. Quantities of free amine groups in the samples treated with M2 and M8 strains within 24 and 48 h of fermentation were significantly different (p≤0.05), compared to the control sample. In the first 24 h of fermentation, no difference was observed in the quantity of free amines of M2 and M8 samples. In the second 24 h, further free amine groups were produced due to the activity of M8 strain in milk. Antioxidant activity of the water-soluble extracts of M2 and M8 samples was significantly (p≤0.05) higher than that of the control sample during fermentation. Antioxidant activity in fractions less than 3 kDa did not show significant differences in M2 and M8 samples at 24 and 48 h of fermentation. In the control sample, no antioxidant activity was observed in fractions less than 3 kDa. The highest ACE inhibitory activity in fractions less than 3 kDa of M8 was observed after 48 h. No angiotensin-I converting enzyme inhibition was seen in fractions less than 3 kDa of M2 and control sample. The RP-HPLC peptide patterns of the fraction less than 3 kDa of M8 and control sample were different, which was a justification for the biological activity in this sample.

There are increasing concerns about transmission of some enteric viruses which are closely related to human-pathogenic strains via animals and their products, contaminated water and foods. Therefore, the use of appropriate processing methods to control these viruses is essential. The aim of this study was to assess the survival of enteric viruses in cheese processing. The role of fat content of cheese (1.5, 2.5 and 3.2%), MS2 bacteriophage spiked levels (100, 102, 104 and 106) in separation of enteric viruses in curd and whey in the press process, the effect of chemical parameters(acidity and pH) on the exchange of enteric viruses in cheese and salt water in processing time were evaluated. MS2 survival was studied by double layer agar and data were assessed in complete randomized design in triplicates. According to the results, it was concluded that MS2 bacteriophage had the maximum survival in whey at fat content of 3.2% and spiked level of 6 log10in which it was 4/67 based on the logarithmic scale. Also, the maximum survival in curd was at fat content of 3.2%. In brine process, the most survival of bacteriophages in cheese and whey was at fatcontent of 3.2% and spiked level of 6 log10. In general, MS2 bacteriophage had the most survival in brine than curd.

One of the most important factors in producing yogurt is choosing the right starter. Native isolates of any country are among the genetic resources of that country, which play a major role in the production and development of the organoleptic properties of fermented products. Therefore, it seems necessary to study the industrial applications of native isolates. In this study, the production of yogurt was investigated by using native starter isolates from traditional Khorasan yogurts and its comparison with yogurts produced with two types of commercial starters.  

Six strains of Streptococcus thermophilus and three strains of Lactobacillus delbrueckii subsp. Bulgaricus isolated from traditional Khorasan yogurts were selected. The proteolytic activity of Streptococcus thermophilus strains was determined according to the method of Erkus et al(2012) and the proteolytic activity of Lactobacillus delbrueckii subsp. Bulgaricus was determined according to the method of Nespolo et al.(2010). Milk acidification activity byall examined strains was evaluated according to the method of Erkus et al.(2012). The production property of gamma-aminobutyric acid of native isolates was also evaluated using the method of Lacroix et al. (2013). Yogurt was produced using commercial starters and native isolates. Acidity and pH were measured according to Iranian National Standard No. 2852. Synersis of yogurt samples was measured using centrifugation according to Çelik (2007) method. In order to measure textural properties, a combination of backward extrusion techniques and Texture Profile Analysis (TPA) was used (Yang et al, 2010). Sensory characteristics of yogurt samples were evaluated by 20 panelists using five-point hedonic scale. This study was conducted based on factorial experiment using a completely randomized design. Statistical analysis of data was performed using Minitab Statistical Software (version 17) and ANOVA. Comparison of means was performed using Tukey’s test at the significant level (p < 0.05).  

The results of proteolytic activity of Lactobacillus delbrueckii subsp. Bulgaricus showed that the L3 code was weaker than the other two strains. All Streptococcus thermophilus strains were positive protease. All Streptococcus thermophilus strains of the study decreased the pH of the milk to 4.6 in less than five hours, and Streptococcus thermophilus strain S6 code, as the fastest acid producer, decreased the pH of the milk to 4.6within 3 and half hours (Figure 2). The results of GABA production showed that among the streptococcus thermophilus strains, S1, S5 and S6 codes had distinct blue discoloration. Among the Lactobacillus strains, except the L3 strain, two other strains produced green color. Of the 18 samples of the yoghurt, S5L2 and S2L2 samples showed the highest decrease in pH and increased in acidity compared to other samples after being stored refrigerated overnight (P <0.05). The other samples had the same pH and acidity changes as the control samples after overnight refrigeration. The results show the ability of yogurt producion by native starters to compete with those produced by commercial starters in terms of technological characteristics. Thus, samples with codes S2L2, S3L1, S3L2, and S1L1 showed less Synersis of   yogurt than commercial starters. This decrease in the Synersis of yogurt might due to the possibility of exopolysaccharide production by these strains. Textural characteristics of yogurt samples were the hardness of the samples in the range of 3 to 4 N, which was significantly different (P <0.05). The lowest hardness was observed for the S3L3, which can be attributed to the poor proteolytic activity of the strain. L3, S6L2, S3L2 and S2L2 had the highest   hardness compared to other compounds and control samples (P <0.05). This differences in the hardness of the samples can be attributed to the possible production of some metabolites by the strains. There was no statistically significant difference in the adhesion properties of the samples (p <0.05). Considering the sensory evaluation scores, it was found that in all respects, S3L3 had the lowest score among the other samples (P <0.05). This was in good correlation with the results of the textural properties of the test. Therefore, this compound was eliminated compared to the control samples. Finally, considering the proteolytic behavior of the strains and the ability to produce acid and GABA, as well as the sensory, rheological and physicochemical properties of 18 samples in comparison to the two control samples, Streptococcus thermophilus strains with codes S4, S2, S5, S1, S6, and Lactobacillus delbrueckii subsp. Bulgaricus strains with codes L1 and L2 have the potential to be used as commercial starters in the form of compounds S1L1, S2L2, S5L1, S6L2, S4L2.

 Rotavirus is the most prevalent cause of severe gastroenteritis, hospitalizations, and deaths among infants and young children, globally. No specific antiviral drug is available against rotavirus infection. 

 The current study aimed to assess the antiviral effect of human cathelicidin antimicrobial peptide LL-37 on rotavirus infection in vitro. 

  This study was conducted in the laboratory conditions of Iran University of Medical Sciences, in Tehran City, Iran. The neutral red assay was performed to assess the cytotoxicity of different concentrations of the peptide on the MA-104 cell line, and its antiviral activity was determined by TCID50 (50% tissue culture infective dose) assay. 

According to the cytotoxicity results, viability maintained more than 90% up to the concentration of 50 μg/mL of LL-37 peptide. The antiviral assays results revealed that the concentration of 50 μg/mL LL-37 peptide could significantly reduce (3.36 log10 TCID50) the production of rotavirus progeny when administered before virus exposure (P= 0.0001). However, no inhibitory effect was detected after cell exposure to virus.

 The obtained data suggested that LL-37 can be considered as a new antiviral agent for protecting infants and young children against gastroenteritis caused by rotaviruses. However, further in vivo investigations are required to confirm this finding.

Yoghurt drink or Doogh has gained great attention in recent years in different countries. On the other hand, this desirable commodity has showed some drawbacks especially from microbial point of view. One of the main problems in Doogh production and storage is considered to be the presence and activity of gas producing microorganisms especially in warm conditions and environments. From the consumer point of view, blowing of container is not acceptable and is regarded as a defect. Since lactic acid bacteria (LAB) possess the potential use as adjunct or co-culture in fermented dairy products for inhibition of gas – producing microorganisms’ especially gas-producing yeasts in doogh, inclusion of these bacteria (LAB) can be a solution for this problem in aforementioned product. In this study, antimicrobial effects of two selected strains of Lactobacillus brevis assigned as M2 and M4 isolated from Motal cheese were investigated on the gas-producing and food spoilage microorganisms in Doogh. Two strains of lactobacillus namely M2 (Lactobacillus brevis KX572376) and M4 (Lactobacillus brevis KX572378) were selected from traditional Motal cheese isolates. Doogh production was carried out according to National Iranian Standard No. 2453. Each of these two strains was inoculated in Doogh at two levels of 106 and 108 cfu / ml and control sample was taken without inoculation followed by subjecting to microbial and sensory analysis at three temperatures of 4, 25 and 37°C, at intervals of 10, 7 and 7 days, respectively. Microbial profiles including coliforms, E. coli, Mold & yeast and Staphylococcus aureus were determined according to National Iranian Standard Number (2 and 1) –5486, 5234 and 5486, 997 and 6806, respectively. Sensory evaluation was carried out according to Iranian National Standard No. 4691. Sensory evaluation parameters such as taste, texture, color and total acceptance were evaluated by 10 senior food industry students. The results showed that sample inoculated with M4106 strain, received the highest score for antimicrobial activity at all three storage temperatures. Results demonstrated that, at 4 ° C, the control sample was contaminated (spoiled) on 50th day and was positive for mold and yeast count, but sample inoculated with M4106 was acceptable (negative) for mold and yeast count. At 25 C, mold growth was detected in control sample on the 14th day of storage, but the sample inoculated with M4106 remained completely un-spoiled until the 21st day. At 37°C, the control sample on day 7 was positive for mold and yeast count, but the sample inoculated with M4106, mold and yeast was not detected until the 14th day. Coliform, Staphylococcus and Escherichia coli counts in M4106 sample were negative. Sensory evaluation was carried out according to Iranian National Standard No. 4691.Sensory evaluation data showed that samples inoculated with M4106 were superior to the control sample. Doogh samples inoculated with Lactobacillus brevis strains experienced acceptable sensory evaluation so that they gained better score than control sample. The highest score was obtained for the M4106 sample. The texture of the Doogh samples showed a decreasing trend at all three temperatures during the storage period. Moisture and pH are factors influencing texture changes during the initial stages of storage. Based on the taste evaluation results, at 4°C, the highest score was related to M4108 until day-20, but from the 20th to the 60th day of storage, the M4106 has gained the highest one. At 25°C until day 7, the highest score belonged to sample M4108 but from this day on, M4106 has been more favorable. At 37°C on production day, highest score for the M4108 sample but on day- 7 and 14, the M4106 took the highest score. Regarding to color index, M2108 has gained the highest score at all 3 temperatures on the production day and for the rest of storage time, the highest scores were obtained for the M4108 and M4106 samples. Maximum total acceptance, was obtained for M2108 on the production day but this was replaced by M4106 for the rest of the time .The results showed that the Lactobacillus strain M4106 strain had the highest antimicrobial activity and the optimum score for sensory evaluation, as well as a significant increase in Doogh shelf life and reduced gas production in the bottle.

Nowadays, consumers prefer foods produced without synthetic preservatives. These chemical preservatives have been gradually replaced by natural preservatives in formulation of edible films and coating. Since, edible films can be applied as carriers of antimicrobial agents, so, these aforementioned ingredients can be incorporated in such films. Among edible films, protein-based films such as whey protein concentrate (WPC)-based films are more attractive because they also supply valuable nutrients and introduce acceptable mechanical resistance. On the other hand, these films present moderate barriers to moisture due to the hydrophilic nature of whey proteins. Essential oils (Eos) can be incorporated in to edible films in order to compensate (overcome) this defect. Since no published research has been found on integrating mastic tree sap (Pistacia atlantica sub sp. kurdica) essential oil into whey protein edible films, this essential oil was applied for WPC-based film in this research. Some species belong to Penicillium have been known as contaminants of dairy and fruit products. Among Penicillium sp., P. expansum is more popular for causing post-harvest damage of apples. In this study, our objective was focused on mechanical and anti-fungal properties of WPC-based films incorporated with mastic gum essential oil.
WPC, mastic tree sap and P. expansum were obtained from Multi Milk Company, Kurdistan mastic Gum Company and Persian Type Collection Culture, respectively. Extraction of EO from mastic gum was accomplished using water distillation or hydro distillation with the help of Clevenger-type apparatus for 5 hours to obtain a pale yellow oil. Solution (10%w/w) of WPC in distilled water was prepared. Glycerol (as plasticizer) was added to WPC solution at a ratio of 1:1 WPC: Glycerol. Then concentrations of EO (1000, 2000, 3000 and 4000 ppm) was added to solution and mixed for 2 min. In the next step, some characteristics of film were measured including: thickness and density, water solubility, stability in acidic and alkaline solutions, water vapor permeability and light transmission / film transparency. Some mechanical properties of films such as tensile strength (TS) and elongation at break (%E) of films were also determined.
Regarding microbial assays, following the activation and preparation of fungi spore, MIC was determined using Agar Dilution Method. Determination of antimicrobial activity of film was performed according to film disk agar diffusion assay
With increasing essential oil concentration, film thickness exhibited increasing trend which was due to entrapment of micro-droplets of essential oil in film. Along with increasing EO concentration in film samples, WVP declined significantly (P-value

Nowadays, consumers prefer foods produced without synthetic preservatives. These chemical preservatives have been gradually replaced by natural preservatives in formulation of edible films and coating. Since, edible films can be applied as carriers of antimicrobial agents, so, these aforementioned ingredients can be incorporated in such films. Among edible films, protein-based films such as whey protein concentrate (WPC)-based films are more attractive because they also supply valuable nutrients and introduce acceptable mechanical resistance. On the other hand, these films present moderate barriers to moisture due to the hydrophilic nature of whey proteins. Essential oils (Eos) can be incorporated in to edible films in order to compensate (overcome) this defect. Since no published research has been found on integrating mastic tree sap (Pistacia atlantica sub sp. kurdica) essential oil into whey protein edible films, this essential oil was applied for WPC-based film in this research. Some species belong to Penicillium have been known as contaminants of dairy and fruit products. Among Penicillium sp., P. expansum is more popular for causing post-harvest damage of apples. In this study, our objective was focused on mechanical and anti-fungal properties of WPC-based films incorporated with mastic gum essential oil.
WPC, mastic tree sap and P. expansum were obtained from Multi Milk Company, Kurdistan mastic Gum Company and Persian Type Collection Culture, respectively. Extraction of EO from mastic gum was accomplished using water distillation or hydro distillation with the help of Clevenger-type apparatus for 5 hours to obtain a pale yellow oil. Solution (10%w/w) of WPC in distilled water was prepared. Glycerol (as plasticizer) was added to WPC solution at a ratio of 1:1 WPC: Glycerol. Then concentrations of EO (1000, 2000, 3000 and 4000 ppm) was added to solution and mixed for 2 min. In the next step, some characteristics of film were measured including: thickness and density, water solubility, stability in acidic and alkaline solutions, water vapor permeability and light transmission / film transparency. Some mechanical properties of films such as tensile strength (TS) and elongation at break (%E) of films were also determined.
Regarding microbial assays, following the activation and preparation of fungi spore, MIC was determined using Agar Dilution Method. Determination of antimicrobial activity of film was performed according to film disk agar diffusion assay
With increasing essential oil concentration, film thickness exhibited increasing trend which was due to entrapment of micro-droplets of essential oil in film. Along with increasing EO concentration in film samples, WVP declined significantly (P-value

In this research, the chemical and microbiological characteristics of white brined cheeses produced with five different starter cultures, namely: traditional kefir grain, commercial kefir, commercial yogurt, traditional yogurt and commercial cheese starter culture, were examined during 60-day ripening period. Results of statistical analysis showed that the type of starter culture had a significant effect on pH, acidity, fat, protein, moisture, enterobacteria, total counts, mold and yeast as well as on lactococcus (p < 0.01), and lactobacillus level (p < 0.05). pH, acidity, fat, protein, total count, mold and yeast, and lactobacillus level (p < 0.01) were significantly affected by starter culture type during ripening period. However, moisture, enterobacteria and lactococcus level in all cheese samples were not affected by ripening period. Whereas other parameters including pH, fat and protein content showed decreasing trend during ripening. Among chemical analyses, cheese produced with traditional kefir had highest pH and cheese produced using commercial kefir showed highest acidity and moisture. Among microbial parameters cheese produced with commercial kefir starter had the lowest total microbial count and after that cheese using traditional kefir starter. It is concluded that traditional kefir grain can be used as a starter culture in production of functional white brined cheese.

Along with the increase in pizza cheese production and consumption, identifying the trends of altering the functional properties of this product in order to control its quality is becoming very important. In this study, the changes in Functional properties of processed pizza cheese and low moisture mozzarella cheese samples collected from local manufactures in Khorasan province, Iran were analyzed. Three samples of commercial processed pizza cheeses and one commercial low moisture Mozzarella cheese as well as a sample of processed pizza cheese prepared according to the formulation previously optimized in our laboratory, were collected and stored at 4 ° C in vacuum packages until the day of experiment. Functional properties of all samples such as stretch length, max load, oiling off and meltability were measured and analyzed in days 0, 14 and 28 after production. In general, Statistical analysis showed that storage time had a significant (p≤ 0.05) effect on all measured properties, so that the stretch properties of low moisture mozzarella cheese and all samples of processed pizza cheese were decreased significantly (p≤ 0.05) during the storage period, whereas meltability and oiling off, follow a significant increase in trend. None of the properties evaluated were out of their standard and acceptance levels at the end of the shelf life, Therefore, it is concluded that the storage of pizza cheese in the fridge instead of freezer up to one month after production is suggested to be an alternative to protect the product from the damage caused by freezing and defrosting while maintaining the quality of the product at the end of the shelf life. The efficacy of TPA and image processing techniques in the measurement of functional properties (stretchability, oiling off and meltability) of pizza cheese samples was also confirmed in this study.

Celiac disease is an autoimmune digestive disease that is caused by the digestion of gluten. and the only treatment of this disease is gluten-free diet. Therefore the production of gluten-free foods with acceptable quality to the patient is important. So the aim of this study was to investigate the effect of soy milk powder (0, 3, 5, 7 and 10%) as a natural additive on the technological and sensory properties of sorghum flour based gluten-free oil cake. Based on the results, the addition of soy milk powder to gluten free cakes formulation (especially at the level of 5%) decreased the specific weight of the dough. Also the results showed that soy milk powder increased moisture content of samples in all levels of addition. Moreover the highest specific volume and porosity were observed in samples containing 5% soy milk powder. In addition, the results of texture evaluation showed by adding soy milk powder the firmness decreased in both periods (2hr and 1 week after baking). The sample containing 10% soy milk powder had firmer texture than the control sample during 2 hours after baking. Finally the samples containing less than 7% soy milk powder gain the highest scores in sensory evaluation and these samples introduced as the best gluten-free products to the market.

Nowadays, attention to foods free from chemical preservatives is on the rise. Recently, consumers have concerned about foods containing these preservatives in their formulation .Therefore,the use of antimicrobial peptides produced by Lactic acid bacteria (LAB) are strongly highlighted. Ribosomally-synthesized peptides, which possess antimicrobial properties, are produced by a vast range of organisms including prokaryotes and Eukaryotes.
Yeasts are the most important microorganisms which are responsible for fruit juice and soft drink spoilage. In case of growth and production of by-products like CO2, acid and other contaminants, the spoilage will be visible.
Lactic acid bacteria isolated from natural, local sources such as dairy products have presented potentially antifungal features against food spoilage fungi. Among these, Rodotorula and Penicillium are regarded as the most critical genera in fruit juice spoilage.
The main objective ofthis study was the evaluation of anti-yeast activity of Lactobacillus plantarum isolates from different stages of Lighvan production against Rodotorulamucilaginosa as fruit juice spoilage indicator. In the next step, technological parameters effects were analyzed on antimicrobial potential of cell-free supernatant of these isolates. Finally, we aimed at finding the most effective isolate on aforementioned yeast.
NineteenLb.plantarumisolates, which were identified previously, were subjected to antifungal assay. For this purpose, RodotorulamucilaginosaPTCC 5257 was selected. Agar spot and Well Diffusion Assay (WDA) were applied for antifungal assay in solid and liquid media, respectively.Determination of yeast colony: Following the cultivation of yeasts in Potato Dextrose Broth, it was determined using Spectrophotometer.
Preparation of Lb.plantarum cell-free supernatant (CFS) was carried out. In agar spot method, clear zones of inhibition around the spotted colonies were evaluated after 24-48h incubation. In WDA, CFS of Lb.plantarum isolates were poured in wells and clear zones were evaluated around each well after 24-48 h incubation.
Technological properties: The influence of different levels of pH (2, 3, 4, 5, 6, and 7) was analyzed on CFS of Lb.plantarum isolates. This assay was done according to Wang et al., 2011. Finally, results were reported using the measurement of clear zone diameter in mm. All experiments were performed in duplicates.
The effects of various temperatures were applied on CFS and remaining the antifungal activity was evaluated according to Rouse et al., 2008. Finally, all CFS of Lb.plantarum isolates were subjected to Proteniase K and antifungal properties of CFS were assayed by WDA according to Ghrairi et al., 2005.
Agar spot results showed the highest and lowest clear zone of inhibition related to C28 and LF49 with 16 and 6 mm diameter, respectively. In this method, 11 out of 19 isolates (60%) presented anti-yeast activity with clear zone formation. In comparison between two incubation temperatures (25 and 30◦C), all isolates stronger clear zone in 30◦C than in 25◦C. This was due to enhancement of yeast growth in 25C rather than in 30C. Also, with respect to the mesophilic nature of Lb.plantarum isolates, the possibility of metabolite production are more likely in 30C. It was reported that antifungal activity of LAB is mostly due to synergistic effect of lactic acid and acetic acid. In agar spot, some colony-associated antimicrobial compounds are responsible for antifungal activity.
In WDA, 8 out of 19 isolates (42%) were positive for their inhibitory effects. The highest anti-yeast activity was seen at pH=2. It seems that antimicrobial compounds are likely more stable at acidic conditions than at alkaline ones. Among isolates, C28 presented the highest stability at alkaline conditions. With pH increase, the antifungal activity decreased so that no anti-yeast activity was seen at pH=7. Regarding the different temperatures, we should mention that thermal resistance of isolate's CFSwitnessed declining trend with increasing of temperature. This fact implies the presence of low- molecular weight compounds in CFS. Finally, all isolate's CFS was subjected to proteinase K. All isolates have lost their anti-yeast activity after enzyme treatment showing their proteinaceous nature.
In WDA, the number of positive isolates showing anti-yeast activity declined in comparison with agar spot. Since some isolates retain their inhibitory activity toward food spoilage yeast at low pH, their CFS can be applied in acidic foods like fruit juice. Also, some isolates showed their antifungal activity at high temperatures (80C and 100C) which are applied for fruit juice pasteurization, so they can be applied in fruit juices as a bio-preservative.

In this research different methods of DNA extraction from Aspergillus niger in tomato paste have been optimized and compared with each other. For this purpose classical optimization techniques and commercial Kit base methods were used. Mold spores of Aspergillus niger at different levels (101, 103 and 105 CFU/g) were added to the tomato paste. After mycelium growth DNA extraction was perfomed by five methods. Different methods employed by use the Liquid nitrogen, ultrasonic and lysis solution in the cell wall. These methods in terms of quality and quantity of DNA extracted were studied using spectrophotometer with NanoDrop. The absence of smear, protein contamination and no presecnce of PCR inhibitors determined with PCR that performed forward and reverse primers. Result of gel electrophoresis and PCR assay showed that Method 1 is the most appropriate method for DNA extraction is the mold of tomato paste.

Food consumers tend to use natural products without any synthetic additives. Therefore, many studies have been conducted to investigate the possibility of replacing synthetic additives with natural substances in various food products.
Annatto dye is a natural carotenoid pigment extracted from the pericarp of BixaorellanaL. seeds. The major fraction of the annatto extract is 9´-cis-bixin that is soluble in oil and 9´-cis-norbixin is the major dye fraction of the alkaline extract that is soluble in water. Annatto dye creates orange to red color in food and to be used as a natural pigment in a variety of food materials including cheese, butter, margarine, confectionary and bakery products, different kinds of drinks, snacks and jams. In addition, annatto dye has antioxidant and antimicrobial activity.
Nowadays, the extraction of natural dye from plant resources has become a common technology. However, complementary information using new methods and optimization of the extraction conditions seems to be necessary in order to accomplish the highest yield of extraction. Response surface method (RSM) is effective and efficient in optimizing color extraction conditions.
In this study, the different conditions of extraction process were optimized through RSM in order to obtain maximum yield and best quality of annatto dye.
Materials Annatto seeds were purchased from Hyderabad, India. All solvents were analytical grade, Merck, Germany.
Extraction of annatto dye
A certain amount of annatto seeds was soaked in n-hexane for 6 hours in order to remove oils. After filtration, the defatted seeds were used for dye extraction. Since chloroform and acetone showed the highest yields of extraction during preliminary experiments, these two solvents and their mixtures were exploited for the final experiments assigning 0 for pure acetone and 100 for pure chloroform. The extracts were filtered through Whatman filter paper NO.1 and then vacuum-dried in the 1410D-2E vacuum oven (Shel Lab, USA) to produce dye powder. Low temperatures (40°C) were applied to prevent thermal dissociation of conjugated double bonds during drying.
Dye measurement
The coloring strength was measured according to Vasu et al. method; model UV-160A spectrophotometer Shimadzu, Japan, at 502 nm in which bixin has the maximum absorbance value when it is dissolved in chloroform.
Determination of extraction efficiency
The obtained powder was weighed and the mass ratio of the powder to the weight of the seeds was taken into account as the extraction yield.
Experimental design
In this study, Minitab® software version 16.1.1 (Minitab Inc. USA. 2010), was used and a five level four factor central composition design was created to investigate the effect of the independent variables such as temperature, extraction time, seed to solvent ratio and chloroform concentration on the dependent variables namely the extraction efficiency and absorbance values.
The values of R2, R2-adj and R2-pred revealed that the full quadratic models were the most adequate for the extraction efficiency and absorbance values.
The all of the linear terms show a significant effect except the extraction time (P 0.05). The interactive terms of extraction temperature* seed to solvent ratio(X1X3) and the seed to solvent ratio*Chloroform concentration (X3X4) had a significant effect on the extraction efficiency (P 0.05).For the absorbance values, the all of the linear terms show a significant effect (P 0.05). The all of interactive terms was insignificant (P> 0.05).
An increase in the extraction efficiency was observed with the increasing temperature. Banik and Pandey while extracting oleanolic acid from Lantana camararoots demonstrated that as temperature increases extraction efficiency improves too. However, at temperatures higher than 70 °C, the annatto seed pigments were degraded and the response was reduced so the quadratic effect of temperature was negative.
The absorbance value was increased by increasing the temperature; however, the absorbance value decreased at higher temperature by thermal decomposition and damage of the conjugate double bond.The absorbance value increased by increasing the chloroform concentration and seed to solvent ratio initially, however, subsequently decreased due to the damage of the conjugate double bond in higher chloroform concentration and saturation of solvent in higher seed to solvent ratio.
Temperature of 48.33 ˚C, extraction time of 2 hr, the ratio of seed to the solvent of 12.88 and chloroform concentration of 100% were found to be as the optimum conditions of the process. The extraction efficiency of 3.95 percent of annatto seed and absorbance value of 0.597 were acquired as the predicted results.

Fructans are an important product of the industry of prebiotics. In addition to their interesting nutritional and health benefit properties, fructans are also used in food formulations for their techno-functional properties such as fat substitute, bulk agent, water retention. Serish (Eremurus spectabilis) belongs to the family of Liliaceae and geographically distributed in the region of South Asia and Central Asia. Their roots accumulate high levels of fructans during their growth and are traditionally used to cure jaundice, liver disorders, stomach irritation, pimples and bone fractures and even as a glue for industrial application. Recently fructan extraction from numerous plants and fungus has drawn the attention of researchers. Also, several methods for fructan extraction have been developed such as hot-water extraction, precipitation by alcohol and ultrasound-assisted extraction. To the best of our knowledge, there are no reports on the fructan extraction from Serish. The present study is considered the first attempt aiming to determine the optimal conditions for water extraction of Serish fructans.
The Serish root powders were obtained from the local medical plant market, Mashhad, Iran. Moisture, ash, fat, protein, Carbohydrate and total dietary fiber were determined according to standard AOAC methods. All variables were examined in triplicate. Conventional extraction was carried out in a water bath. Total carbohydrate was assayed colorimetrically using the phenol–sulphuric acid method. The concentrations of soluble reducing sugars were measured using a 3,5-dinitrosalicylic acid (DNS) method. The fructan content was measured by the difference between total carbohydrate and reducing sugars. The percentage of fructan yield (%) was evaluated based on equation of Lingyun, Jianhua, Xiaodong & Yalin (2007). The purity was evaluated according to the method of Paseephol, Small & Sherkat (2007). As an index of degree of polymerization, the average chain length, was calculated according to Lingyun, Jianhua, Xiaodong & Yalin (2007). A Box-Behnken design was constructed using the software Design Expert Version 6.0.10 and was used for estimating the effect of independent variables on the extraction parameters. Three extraction variables considered for this research were x1 (extraction time), x2 (extraction temperature) and x3 (water: solid) for conventional extraction method. Lack of fit, coefficients of determination (R2), adj-R2, coefficient of variation (CV) and significant probabilities were calculated to check the model adequacy. Optimization was based on generation of the best results for fructan extraction. In order to determine the validity of the model, the experimental and predicted values were compared by paired t-test.
It has a marked amount of protein and fats. The ash value is relatively high, suggesting an important mineral content. The composition of total fiber suggests its possible use as a source of dietary fiber for enrichment of foods. In addition, results show that Serish root powder is a polysaccharide-rich material. The results indicated that extraction temperature has the most effect on the extraction yield. Increase of time, temperature and water to solid ratio led to significantly increase in extraction yield. Considering the significant quadratic term of extraction time, it becomes clear that yield rises as extraction time increase from 0 to 22.5 min but it decreases at higher times. The yield increase between 0 to 22.5 min might be due to the time requirement for contact of fructan to the release medium where the liquid penetrated into the Serish powder, dissolved the fructan and subsequently diffused out from the root. On the other hand, the yield decrease after 22.5 min may be ascribed to degradation of fructan to free sugar and enhancement of impurities extraction at higher times. When extraction time goes by certain threshold, the yield started to decrease. The yield showed a large tendency to increase when the extraction temperature was increased. This is maybe due to the enhancement of the mass transfer resulting from the increased solubility of fructan and the decreased viscosity of the solvent. Yield was increased by portion of water to solid. This might be attributed to the availability of liquid that increases the driving force of fructan out of the root. Based on the sum of squares, temperature had the most effect on degree of polymerization. The results indicated that increase of time, temperature and W/S ratio resulted in increase of the degree of polymerization which might be due to the enhancement of overall carbohydrates extraction. On the other hand, the degree of polymerization of extracted fructan was lower than 10. This is probably because the disruption of fructan branch to reducing sugars with increasing temperature that leads to chain length decrease. Thus, the produced oligosaccharides could be used as sweetener. W/S ratio had the most effect on purity. The results showed that increase of time, temperature and W/S ratio resulted in increase of the purity which might be due to the enhancement of overall carbohydrates extraction. With the increase in extraction time, the purity of extract increased gradually, but decreased after the purity reached a maximum at 22.5 min. This decrease may be ascribed to degradation of fructan to free sugar and enhancement of impurities extraction at higher times. Multiple response optimizations were performed to measure the optimum levels of independent variables to achieve the desired response goals. Extraction yield and purity were desired maximal.
The final results for this optimization was found to be extraction time of 28.38 min, extraction temperature of 88ºC and water to solid ratio of 50:1 v⁄w. Response surface methodology was an efficient statistical tool to model the influence of extraction conditions of fructan from Serish root powder on the extraction yield. These results also suggested that by modifying the proportion of these components, a large range of variations may be obtained. There was a good agreement between the experimental data and their predicted counterparts, showing the effectiveness of the proposed conditions and reliability of Box–Behnken analysis on fructan precipitation.

One of the most important aspects of food preservation is controlling the growth of microorganisms, which if overlooked it leads to uncontrolled growth of microorganisms associated with food spoilage and food poisoning. Microbial contamination of foods is important because of pathogens are capable to transfer to foods during the processing, distribution, and storage. Escherichia coli and Bacillus cereus can cause spoilage in food; intake food contains plenty of bacteria and toxic. Therefore it is important to eliminate or control these bacteria safely. Ultraviolet (UV) radiation is considered as non-ionizing radiation and the first time in 1940 was used as a method for infection elimination in air. This approach nowadays is widely used for controlling microbial growth and as disinfection in food industry. Wavelength range of ultraviolet radiation is approximately 328-210 nm. The beam is naturally present in the sunlight. The bactericidal effect of UV irradiation depends on the type of bacteria, the distance, and dose of radiation. The most cytotoxic effect of UV irradiation is obtained at the wavelength of 260 nm, which corresponds to the intense absorption of energy by organic bases in the nucleic acid. UV irradiation causes radicals generation, which subsequently attack the nucleic acid and develop mutations in their genomes and gene transcription and translation processes. In this study, the antibacterial effect of different exposure times of ultraviolet radiation on the growth of E. coli and B. cereus was evaluated.

All media used in this study was procured from Merck Company. Ultraviolet device (Camag, USA) was used at wavelength of 254 nm, Nr= 29000, Amp= 0.25. B. cereus isolation: 1 mL of different dilutions of rice (0.1, 0.01, and 0.001) was transferred to Brain-heart infusion (BHI) and it was incubated at 32 °C for 24 h. A loop containing the bacteria was then transferred to Mannitol Egg Yolk Polymyxin (MYP) agar and it was incubated at 35 °C for 24 h. B. cereus produce big and round colonies, with a halo around the colonies. Starch test was carried out as confirming test for B. cereus colonies. Briefly, some colonies of B. cereus were added to test tube with sterile distilled water containing starch and a few drops of lugol. Development of blue color indicates the presence of B. cereus due to starch hydrolysis. E. coli isolation: E. coli was isolated from raw milk following the method described by Kargar et al. (2005). Briefly, raw milk was first homogenized; 0.1 ml of each dilution of homogenized raw milk was inoculated on Escherichia coli broth medium containing 20 mg novobiocin. E. coli was then isolated after transferring the former media on EMB specific culture and incubation at 36 °C for 24 h. After confirming colonies by Durham tube and complementary tests, pure cultures were obtained from them by streak-plate method. UV irradiation: A loop of E. coli colonies was transferred to nutrient broth and it was treated with UV beam (254 nm) at three times (40, 60, and 80 s). After preparing dilution of 0.0001 for each of the treatments and incubating for 24 h, survival curve was plotted. These operations were also carried out on B. ceruse colonies. A control sample also was considered for each examined bacterium.

Rate of Bacillus cereus growth was reduced under UV radiation. As it is shown, Death curve of E. coli, E. coli count was decreased by increasing the time of UV radiation, so that count of this bacteria reached to about zero after UV radiation for 80 s. However, reduction of B. cereus count was less than E. coli count at same wavelength (254 nm) and time of irradiation. This revealed that B. cereus have more resistance to UV radiation compared to E. coli. These results were consistent to observation of Sharp (1940) who evaluate the effects of UV light on bacteria suspended in air and reported that required energy for air sterilization containing B. cereus is more than twice the energy is needed to eliminate E. coli. UV light more penetrates to cell wall of Gram-negative bacteria compared to Gram-positive bacteria due to having a small amount of peptidoglycan in the cell wall and caused mutations in regulating genes of transcription and translation.

The efficiency of the two main processes of cell is reduced in the presence of UV irradiation and leads to growth reduction and death. The more resistance of B. cereus can be for several reasons, such as having a thicker cell wall compared to E. coli, and the capability to produce spore, and the capability to proofing mutations.

Annatto dye is used extensively in food industry that has antibacterial and antioxidant properties. Aim of this paper was comparison of the antibacterial and antioxidant properties of annatto dye was extracted by conventional and ultrasound-assisted extraction (UAE) methods. In this experimental study minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of annatto dye against the bacteria were determined by agar dilution method. Antioxidant activity of annatto dye was evaluated by DPPH method. Gram-positive bacteria show more sensitivity to annatto dye than Gram-negative bacteria. Annatto dye extracted by UAE has more antibacterial and antioxidant activity compared to conventional method. Bacillus subtilis and Escherichia coli have the highest and the lowest sensitivity to annatto dye, respectively. Annatto dye extracted by UAE showed a bactericidal effect against Salmonella enteritidis, however the dye extracted by conventional method the opposite is true.

The objective of this experiment was to investigate the antimould effect of 19 Lactobacillus plantarum strains isolated from different production stages of Lighvan cheese (3, 8 and 8 strains from raw milk, curd and fresh cheese stages, respectively) a traditional raw milk cheese, on Penicillium expansum (PTCC 89046) as an indicator in fruit juice spoilage. This antimould spectrum was determined by agar spot and well diffusion method, followed by determination the influence of different technological or physico-chemical factors including temperature (80°C for 1 h, 100°C for 10 min, 100°C for 30 min and 121° C for 15 min) and pH(2 to 7) and different dilution (Titre test). Serial twofold dilutions were conducted to the CFE in order to assess of CFE Titre against mould indicator. Findings revealed that Lactobacillus plantarum strain C28 has the highest antimould properties in both antimicrobial methods (Agar Spot and Well Diffussion Assay) and antimould effect showed decreasing trend with pH increasing. In 121 ° C for 15 min, no antimould effect was observed. The Lactobacillus plantarum strain C28 showed the highest titre factor of 160 (AU / ml). Finally, we can assume that these strains which isolated from different production stages of Lighvan cheese or their Cell Free Extract (CFE) can be used as biopreservative in food systems.

The goal of this study was applying the genetic algorithm–artificial neural network (GA-ANN) modeling to predict the antibacterial effect of annatto dye on Escherichia coli population in mayonnaise. Annatto has antimicrobial and antioxidant properties in foods. Annatto dye was extracted and after filtration and concentration, was dried by vacuum oven. In this study, sauce samples containing 0, 0.1, 0.2 and 0.4 percent of annatto dye were prepared and stored at 4 and 25 ˚C. Sampling and colony counting were performed during 17 days and in triplicate. In order to predict the Escherichia coli population multi-layer perceptron neural network with 3 inputs and 1 output were used. Genetic algorithm method was used to optimization number of neurons in ANN hidden layer. The results showed a network with 7 neurons in hidden layer and using a Sigmoid tangent transfer function and the Levenberg–Marquardt (LM) optimization technique and 30%-20%-50% for training/ testing/ validating process can be well predict the Escherichia coli population (r=0.999) in the presence of annatto dye. Sensitivity analysis results by optimum ANN showed the storage time as the most factor for the predicting the Escherichia coli population.

Annatto color is one of the oldest of natural carotenoids that have wide applications in food technology. Annatto color is the second natural color additives used in world industry, of economic. It is predicted that demand for it is increasing day by day. Color extraction from annatto seed is done by conventional methods, mainly. Little information is available about the use of new techniques such as response surface methodology of ultrasound technology in the extraction of annatto color. The subject of this study was to optimize the ultrasound-assistant extraction process of annatto color and determination of the best process conditions by using response surface methodology and central square design. The central composite design was used in order to evaluate the effect of extraction temperature (80-20 °C), extraction time (10-2 min), seed to solvent ratio (5-20 %) and duty cycle (0.2-0.8 s), on efficiency of dye extraction from annatto seed and to optimize the extraction process. ANOVA shows the seed to solvent ratio variable (X4) and it square effect (X42) have the greatest impact on dye extraction from the annatto seeds. In temperature of 72.7 °C, extraction time of 7.25 min, the seed to solvent ratio of 14 percent and duty cycle of 0.8 s were found as the optimum conditions of the ultrasound-assistant extraction process in order to obtain the maximum efficiency of color under which the absorbance value and extraction efficiency was determined as 0.865 and 6.35 percent of annatto seed, respectively.

Today, disadvantages of antibiotics and synthetic preservatives have been identified, and researchers are seeking natural and safe alternatives. Annatto dye is one of the commonly used dyes in the food industry, which has antimicrobial and antioxidant properties. The objective of this study was to determine the antimicrobial effect of annatto dye on some pathogenic bacteria. In this study, annatto dye was extracted from annatto seeds by maceration methods and after filtration, it was powdered by vacuum oven. Antimicrobial activity was evaluated by disc diffusion method and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using agar dilution method against Staphylococcus aureus, listeria innocua, Bacillus cereus and Salmonella enteritidis. In this study, Bacillus cereus and Salmonella enteritidis, respectively, showed the highest and the lowest sensitivity to annatto dye. S. enteritidis had the highest MIC among the tested bacteria, and MBC was not observed only for S. enteritidis in the tested concentrations of annatto dye. According to the results of this study, annatto dye was effective on the growth of all tested bacteria. Also, annatto dye had more antimicrobial effect on the tested gram-positive bacteria compared to gram-negative bacteria. Thus, considering the results of the experiment, annatto dye can be used as an inhibitor of bacterial growth.

Ozone is a strong oxidant and a potent disinfecting agent. There are numerous application areas of ozone in food industry. While there are many investigations on the application of ozone in food industry, relatively little information is available on the potential of ozone to reduce microbial populations in fresh-cut fruits and vegetables and the visual quality of lettuce. In this study, ozone water was applied at five concentrations (0.6, 0.8, 1.2, 1.6 and 2 ppm) for four exposure times (1, 3, 5 and 10 min) on natural microflora and E. coli O157:H7 and Salmonella inoculated of lettuce. The reduction in the total bacterial count, yeast and mold, total coliform, as well as lactic acid bacteria counts were examined. The promising results indicated the efficacy of ozone water to reduce the microbial populations on lettuce. In the best condition, the inoculated samples of E. coli O157:H7 (ATCC 35150, NCTC 12900), Salmonella typhi morium (ATCC 14028, NCTC 12023) and Salmonella enterica subsp, enterica (PTCC 1709) on lettuce were decreased further than 2 log10 cfu/g. The results showed the population of aerobic mesophilic bacteria, yeast/ moulds, total coliforms and lactic acid bacteria were decreased to 1.54, 0.94, 1.94 and 1.35 log10 cfu/g respectively. The method of ozone generation, type of application, as well as the optimal exposure time and concentration of ozone as an antimicrobial agent on lettuce is mentioned in detail.

Fructan is widely used throughout the world for its health-promoting and functional properties. Eremurus spectabilis which has traditionally been used in different industries as well as in folk medicine is considered one of the valuable resources of fructan. However, there is little information about fructan extraction from this plant. Ultrasound-assisted extraction is considered one of the most important methods for extraction of the most valuable compounds from plant sources and is applicable in both laboratory and industrial scales. In this study, boxbehnken design was used in order to investigate the effect of time (5-40 min), temperature (30- 70º C) and ultrasound amplitude (20–100 %) on the yield of fructan extraction from Eremurus spectabilis and optimization the extraction process using ultrasound waves. To describe the extraction yield, a first-order model was developed and verified its performance. The model was subsequently used to assess the appropriate conditions affected by the interaction between parameters and estimate the best process conditions with maximum extraction yield. Results showed that maximum yield is achieved with extraction time of 29.31 min, extraction temperature of 60º C and ultrasound amplitude of 80.04%.

The objective of this study was to evaluate lactic flora identification in fresh (one-day) and ripened (90-day) Koozeh cheese samples as one of the raw milk cheeses. In first step, in order to isolate the different genera of Lactic acid bacteria (LAB), selective and differential (corresponding) media were used as follow: MRS for lactobacilli and pediococci, MRS+ vancomycin for leuconostocs, M17 for lactococci and KAA for enterococci. Totally, 48 single, purified colonies were selected and identified using confirmatory, biochemical and phenotypic tests down to the genus level. Lactobacilli (33.33%), lactococci (12.5%), pediococci (2.08%), enterococci (47.91%) and aerococci (4.16%) were determined as the most abundant genera. At last, carbohydrate fermentation profile using API 50 CH and API 20 STREP kits was used for identification down to species level. Finally, following species were identified: Lactobacillus. plantarum, Lb. brevis, Lb. lindneri, Lb. helveticus, Lb. delbrueckii ssp. delbrueckii, Lb. pentosus, Lb. fermentum, Lactococcus. lactis ssp. lactis, Enterococcus. faecium, Ent. faecalis, Ent. avium, Ent. durans and Aerococcus. viridans. In fresh cheese, the Lactococci and lactobacilli genera were predominant but in ripened cheese the enterococci replaced them. Predominant species in fresh cheese were as follow: Lac. lactis ssp. lactis (44.44%) and Lb. plantarum (22.22%) but Ent. faecium (43.58%), Lb. brevis (12.82%) and Ent. faecalis (7.69%) constituted the major part in ripened cheese. We can mention that these predominant lactic acid bacteria play an important role during ripening and also flavor production in raw milk cheeses like Koozeh. So, more precise identification is very necessary using culture- based molecular and culture- independent methods down to strain level.

We investigated the microbiological quality of raw vegetables in Mashhad, Iran. In order to document the incidence of indicator and pathogenic microorganisms in this area. ninety eghit raw vegetable samples collected during 7 months were analyzed. All samples were examined for the presence of aerobic mesophilic bacteria, coliforms, Enterobacteriaceae, Escherichia coli, Escherichia coli O157:H7, Salmonella spp., Staphylococcus aureus, yeast and mould. Our data showed that the incidence levels of aerobic mesophilic bacteria was less than 107 cfu/g on 83% raw vegetables and 100% of raw vegetables were contained Entrobacteriace and total coliforms, and their range varied from 1 log to 6 log cfu/g. The mean counts of Lactic acid bacteria and yeasts and moulds were 4.1 log cfu/g and 4.5 log cfu/g, respectively, and the incidence levels of yeasts and moulds in 83% of raw vegetables was less than 5 log cfu/g. Our results were similar with other studies that determined microbial levels on raw vegetables. 12.7% of samples raw vegetables contained E.coli, but only 4.1% were higher than ≥ 2 log cfu/g. The incidence levels for E.coli O157:H7 and Salmonella on raw vegetables were 6% and 12.7% respectively. 94.9% of raw vegetables were contaminated with S. aureus and 7.8% of them were coagulase positive.