List of Articles Starter culture

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  1 - Comparison of the Antibiotic Resistance of Lactobacilli Isolated from Traditional Dairy Products with the Antibiotic Resistance of Lactobacilli Isolated from Industrially Produced Dairy Products
  B. Moghimi M. Ghobadi Dana R. Shapouri
  Introduction: Lactobacilli are a member of the Lactic Acid Bacteria (LAB) family that are used as starter culture in the production of industrial and traditional dairy products. Lactobacilli could potentially play an important role in the transition of antibiotic resist More

  Introduction: Lactobacilli are a member of the Lactic Acid Bacteria (LAB) family that are used as starter culture in the production of industrial and traditional dairy products. Lactobacilli could potentially play an important role in the transition of antibiotic resistance to gastrointestinal bacteria or pathogenic bacteria.Materials and Methods: In this study, Lactobacilli were isolated from traditional yogurts, yogurt drinks and industrial yogurts and yogurt drinks and the antibiotic resistance to  13 antibiotic including: Penicillin, Ampicillin, Tetracycline, Erythromycin, Gentamicin, Streptomycin, Vancomycin, Nalidixic acid, Trimethoprim Sulfamethoxazole, Kanamycin, Rifampin, Ciprofloxacin, and Chloramphenicol have been investigated and the results were compared.Results: According to the results, vancomycin resistance was the most prevalent phenotype in traditional yogurt (45.8%) and yogurt drink (40%) and in industrial yogurt (59%) and yogurt drink (50%) respectively. Except in the case of Penicillin and rifampin there was no significant difference between the resistances of Lactobacilli isolated from industrial yogurt to other studied antibiotics in this study are compared to the resistance of Lactobacillus isolated from traditional yogurt. Ciprofloxacin resistance in Lactobacilli isolated from industrial yogurt drink is significantly higher than the resistance of Lactobacilli isolated from traditional yogurt drink and there was no significant difference between the resistances to the other studied antibiotics inLactobacillus isolated from industrial and traditional yogurt drink.Conclusion:Antibiotic resistance was observed in Lactobacilli isolates of traditional and industrial samples. It seems that there is a need to pay attention to the antibiotic resistance in starter cultures used in the food industries in order to prevent the spread of antibiotic resistance. Manuscript profile
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  2 - Effect of Heracleum persicum (Golpar) essential oil on some microbial, chemical and sensory characteristics of heat treated Dough
  A.R. Yousefi H. Sheikhloie Bonab J. Seyfi Hachesou M. Hatami
  Nowadays, many studies have been conducted to substitute the chemical preservatives with naturally occurring compounds, including plant essential oils. In this research, Golpar essential oil was added to Dough samples at concentrations of 0 (control), 100, 250, 500 and More

  Nowadays, many studies have been conducted to substitute the chemical preservatives with naturally occurring compounds, including plant essential oils. In this research, Golpar essential oil was added to Dough samples at concentrations of 0 (control), 100, 250, 500 and 1000 ml/l and after packaging, were stored at refrigerator for 40 days. The samples were subjected to microbial (enumeration of yeasts and molds, yoghurt starter bacteria and coliforms), chemical (acidity, pH, fat and solids-non-fat) as well as sensory characteristics (taste and odor) assays. Results showed that with the increasing of the essence concentration, the populations of yeast and mold were reduced (P<0.05), however, the effect of Golpar essential oil on starter bacteria was insignificant. The number of starter bacteria increased towards day 10, followed by a decrease until the end of storage time. Although during the storage period, acidity and pH were increased and decreased, respectively, the effect of essential oil on fat content and solids-non-fat was not significant. Sensory evaluations in terms of taste and odor revealed that the treated samples had significant (p< 0.05) difference in comparison with control groups. Besides, the samples containing 250 µl/l gained the highest score. It was concluded that Golpar essential oil can be efficiently used in Dough formula as a good natural preservative and flavoring agent. Manuscript profile
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  3 - Behavior of various strains of Yersinia enterocolitica in Ultra-filtered cheese and inhibitory effect of lactic starter bacteria
  رضا Vaseghi Bakhshayesh شهرام Hanifian
     This study aimed to assess the behavior of various strains of Yersinia enterocolitica in ultra-filtered (UF) cheese and to evaluate the inhibitory effect of lactic starter bacteria on survival of Y. enterocolitica. To this end, pasteurized ultra-filtered mi More

     This study aimed to assess the behavior of various strains of Yersinia enterocolitica in ultra-filtered (UF) cheese and to evaluate the inhibitory effect of lactic starter bacteria on survival of Y. enterocolitica. To this end, pasteurized ultra-filtered milk was inoculated with 3 log cfu/g of two standard strains (DSM 11502 and DSM 9499) and one native strain of Y. enterocolitica. UF cheese samples were produced with and without starter culture. Enumeration of Y. enterocolitica was performed at the time of inoculation, after incubation time and during the 2-months storage period on CIN agar. The enumerated colonies were confirmed by PCR. Results revealed that after incubation, the populations of Y. enterocolitica in both groups increased by 4.14 log cfu/g (P < 0.01). However, during the storage period the number of Y. enterocolitica decreased only in the samples made with starter cultures. pH values revealed a significant difference (P < 0.01) between the samples made with and without starter culture; therefore, it seems that acidic pH is the major factor inhibiting the survival of Y. enterocolitica in UF cheese. Besides, a significantly (P < 0.01) different behavior was observed among native and standard strains. Considering the inhibitory effect of starter bacteria,it seems that creation of proper conditions in terms of temperature and the time necessary for proliferation and activity of starter bacteria or application of cultures capable of producing antagonistic products can be effective in controlling possible microbial contaminations along with the development of desirable aroma and texture in UF cheese. Manuscript profile
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  4 - Effect of different concentrations of nisin on starter culture of model Cheeses manufactured from ultrafiltrated milk
  Kh Mohammadi حسین Jodeiri
     Nisin is a natural preservative produced by strains of Lactococcuslactis subsp. Lactis, has been approved for use in food by the Joint Food and Agricultural Organization/World Health Organization (FAO/WHO) Committee on Food Additives and has been awarded ge More

     Nisin is a natural preservative produced by strains of Lactococcuslactis subsp. Lactis, has been approved for use in food by the Joint Food and Agricultural Organization/World Health Organization (FAO/WHO) Committee on Food Additives and has been awarded generally recognized as safe (GRAS). It remains the only bacteriocin allowed in food as an addedpreservative. Nisin has a broad spectrum of antimicrobial activity againstgram-positive bacteria, thus one of the problems associated with nisin application is inhibition of starter culture and prevention of ripening, which is required for development of cheese characteristics during ripening. In the current study, the effects of different concentrations of nisin and temperature on growth and activity of lactic acid bacteria in model cheeses manufactured from ultrafiltrated milk was evaluated. Cheese samples were supplemented with nisin at concentrations of 0, 2, 4 and 6 µg/g and stored at 8 and 25 °C up to 60 days. Microbiological and physico-chemical properties of the cheese samples were analyzedat 0, 1, 8, 15, 30, 45 and 60 days. Results showed that addition of nisin at concentrations of 4 and 6 µg/g affects (p<0.01) the growth of lactic acid bacteria and so prevents pH reductionduring cheese ripening (p<0.01). Moreover, roomtemperature decreased significantly (p<0.01)nisin activity. According to the results, nisin at concentrations less than 4 µg/g along with refrigeratorstorage temperature could be used as a natural preservative in Cheese manufactured fromultrafiltered milk. Manuscript profile
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  5 - Combined effects of different concentrations of starter culture and incubation temperatures on physicochemical, microbial and sensory features of stirred yogurt produced from Sheep’s milk
  Golsa Mehrabadiyan Ali Reza Shahab Lavasani Sara Movahed
  Yogurt gels are a type of soft solid. Streptococcus thermophilus and Lactobacillus bulgaricus are yogurt starter cultures widely used in the dairy industry. Co-culture of these bacteria leads to higher biomass yield than their separate single strain culture. Incubation More

  Yogurt gels are a type of soft solid. Streptococcus thermophilus and Lactobacillus bulgaricus are yogurt starter cultures widely used in the dairy industry. Co-culture of these bacteria leads to higher biomass yield than their separate single strain culture. Incubation temperature also affected some physicochemical and sensory features of yogurt, so the aim of this work is to determined physicochemical and sensory features of yogurt containing different concentrations starter and different incubation temperatures made from sheep’s milk. The preparation of all treatments(T) as follows, Yogurt produced from: 2% starter culture and incubation temperature 42˚C ,T(A);  1% starter culture and incubation temperature 37˚C,T(B); 1% starter culture and incubation temperature 42˚C,T(C: as a Control); 2% starter culture and incubation temperature 37ᵒC, T(D); 3% starter culture and incubation temperature 42˚C, T(E) and 3% starter culture and incubation temperature 37˚C,T(F).the results indicated that fat%, dry matter% and moisture% did not change during 22 days of storage period and parallel to drop of pH, acidity (Dornic scale) continuously increased. The protein content of treatments B,C; continuously increased during 22 days storage period. The starter culture bacterial counts of yogurt  showed that both Streptococcus thermophilus and Lactobacillus bulgaricus decreased during storage period. Sensory evaluation was performed for two features (flavor and texture). The scores for these features decreased during storage period but scores that allocated for treatment D were highly similar to control sample. According to above mentioned, it was concluded that treatment D was more similar to treatment C as a control sample. Manuscript profile