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Starter Culture (starter + culture)
Selected AbstractsEffects of Leuconostoc mesenteroides Starter Culture on Fermentation of Cabbage with Reduced Salt ConcentrationsJOURNAL OF FOOD SCIENCE, Issue 5 2007Suzanne Johanningsmeier ABSTRACT:, Sauerkraut fermentations rely upon selection of naturally occurring lactic acid bacteria by addition of 2.0% to 2.25% granulated sodium chloride (NaCl) to shredded cabbage. Excess brine generated is a waste product with high levels of organic material (BOD) and nonbiodegradable NaCl. The objective was to determine whether addition of Leuconostoc mesenteroides starter culture to reduced-salt cabbage fermentations would yield sauerkraut with reproducible and acceptable chemical composition and sensory qualities. Shredded cabbage was salted with 0.5%, 1.0%, or 2.0% NaCl (wt/wt) at 2 starter culture levels, none or L. mesenteroides strain LA 81, ATCC 8293 (106 CFU/g). Fermentation products were quantified by high-performance liquid chromatography, and pH was measured during the initial stages of fermentation and after 10 mo storage at 18 °C. A trained descriptive sensory panel used category scales to rate the flavor and texture of selected sauerkrauts. A modified Kramer shear test was used to measure firmness. Cabbage fermented with L. mesenteroides consistently resulted in sauerkraut with firm texture and reduced off-flavors across all salt levels (P < 0.05). Conversely, sauerkraut quality was highly variable, with softening and off-flavors occurring as salt concentrations were decreased in natural fermentations (P < 0.05). Fermentations were rapid, with a more uniform decline in pH when starter culture was added. L. mesenteroides addition to cabbage fermentations ensured that texture and flavor quality were retained, while allowing 50% NaCl reduction. Application of this technology to commercial sauerkraut production could improve the uniformity of fermentations and substantially reduce generation of nonbiodegradable chloride waste. [source] Alternative Drying Processes for the Industrial Preservation of Lactic Acid Starter CulturesBIOTECHNOLOGY PROGRESS, Issue 2 2007Chalat Santivarangkna The preservation of lactic acid starter cultures by alternative drying processes has attracted increasing attention due to the high costs and energy consumption of freezing and freeze drying. This review thus aims to provide a survey regarding the state of knowledge of starter culture production at high levels of viability. The results from numerous studies on various drying processes and lactic acid bacteria are summarized. The alternative drying processes considered, such as spray drying, fluidized bed drying, and vacuum drying, are mainly of industrial interest. The features, advantages, and disadvantages of these drying processes are described. In conclusion, the important factors that need to be considered, standardized, or optimized to achieve high levels of viability include intrinsic tolerance of cultures, growth media and conditions, stress induction, cell harvesting conditions, protective agents, rehydration conditions, enumeration of cells, and storage conditions. [source] PROTECTIVE CULTURES USED FOR THE BIOPRESERVATION OF HORSE MEAT FERMENTED SAUSAGE: MICROBIAL AND PHYSICOCHEMICAL CHARACTERIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2008JAZILA EL MALTI ABSTRACT In this paper, 150 isolates, originating from horse meat, were subjected to step-by-step screening and characterization to search for potential protective cultures to be used in the meat industry. Isolates were first tested on their homofermentative and salt tolerance. Second, the antibacterial capacities toward Listeria monocytogenes were determined in an agar spot test. In total, 50% of the tested isolates were inhibitory toward Listeria monocytogenes. However, only 12 isolates produced a bacteriocin. Finally, three isolates with the strong bacteriocin activity were evaluated on their competitive nature by comparing their growth rate, acidifying character and lactic acid production at 15C under anaerobic conditions in a liquid broth. All three isolates combined a fast growth rate with a deep and rapid acidification caused by the production of high levels of lactic acid. Lactobacillus sakei was used as starter culture for producing sausage horse meat. In this study, fermentations were followed analyzing the microbiological and physicochemical aspects of this product. The sausages were characterized by an important microbial activity of lactic acid bacteria that resulted in a product with a final pH of about 4.56. No Listeria monocytogenes, Salmonella spp. or sulfite reducing clostridia were ever isolated from the raw materials or the fermented sausages during the maturation, underlining the microbial safety of this product. The final water activity of the product was 0.85. Starter cultures showed that Lactobacillus sakei was really efficient in reducing the amine production since this strain caused a quick pH drop during sausage fermentation. PRACTICAL APPLICATIONS A starter culture can be defined as a microbial preparation of large numbers of cells of at least one microorganism to be added to a raw material to produce a fermented food by accelerating and steering its fermentation process. The group of lactic acid bacteria (LAB) occupies a central role in these processes, and has a long and safe history of application and consumption in the production of fermented foods and beverages. They cause rapid acidification of the raw material through the production of organic acids, mainly lactic acid. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides and several enzymes is of importance. The main reason for suitability of LAB is their natural origin, and they can contribute to food safety and/or offer one or more organoleptic, technological, nutritional or health advantages. [source] The effects of starter culture on chemical composition, microbiological and sensory characteristics of Turkish Ka,ar Cheese during ripeningINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2007DURMU Ka,ar cheese samples were produced from raw milk and starter culture-added pasteurized milk. Chemical, microbiological and organoleptic properties of ka,ar cheeses were analysed at certain times during the ripening periods (on the 1st, 7th, 15th, 30th, 60th, 90th days). Generally, chemical parameters were not affected by starter culture. The pH, ripening index, water-soluble nitrogen and non-protein nitrogen did not show significant differences between the cheese samples. The addition of starter affected the microbiological quality of the cheeses. Starter culture-added ka,ar cheeses contained low levels of total aerobic mesophilic bacteria, moulds and yeasts, and coliforms, and achieved higher organoleptic scores than those of cheeses made from raw milk. The starter cultures contributed to acidity and microbial quality of the cheese. [source] Probiotic lactic acid bacteria from Kung-Som: isolation, screening, inhibition of pathogenic bacteriaINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2010Noraphat Hwanhlem Summary Lactic acid bacteria (LAB) were isolated from Kung-Som at various fermentation periods. Only ten strains, named D2SM22, D6SM3, D6SM24, D6SM26, D8SM21, D10SM5, D10SM11, D10SM16, D10SM20 and D16SM26 showed a survival rate of more than 50% under the simulated gastric juice. After being subjected to simulated gastric juice, four strains (D6SM3, D8SM21, D10SM16 and D10SM20) showed a survival rate of more than 50% in simulated small intestinal juices. Growth of strain D6SM3, D8SM21 and D10SM16 under micro-aerobic and anaerobic conditions was not different. Tested pathogenic strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus and Salmonella sp.) were inhibited by probiotic LAB. However, none of strains could produce bacteriocins. All strains were identified as Lactobacillus plantarum. No differences in pH, acidity, LAB count and liking scores between Kung-Som produced with starter culture and conventional method were observed (P > 0.01). [source] Effect of fat and non-fat dry matter of milk, and starter type, on the rheological properties of set during the coagulation processINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2007Özlem Gün Summary The effect of fat and non-fat dry matter (NFDM) of milk, and starter type, on the rheological properties of set yoghurt during the coagulation process was studied using a rotational viscosimeter. The pH was monitored simultaneously with viscosity readings. Recombined milk was cultured with yoghurt starter culture (YC), consisting of Streptococcus thermophilus and Lactobacillus bulgaricus, or ABT1, consisting of S. thermophilus, Lactobacillus acidophilus and bifidobacteria, at 40 °C until the pH dropped to 4.7. Yoghurt made with ABT1 had higher viscosity values than yoghurt made with YC. The NFDM content of milk had a major effect on the viscosity of curd made using YC or ABT1. For YC and ABT1, three stages were identified on the viscosity,incubation time curves and viscosity behaviour was different in each stage. [source] Effect of manufacturing treatments on the rheological character of Mozzarella cheese made from microfiltration retentate depleted of whey proteins,INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2001Randall L. Brandsma Low-moisture, part-skim (LMPS) Mozzarella cheeses were made from highly concentrated skim milk microfiltration (MF) retentate and butteroil. Differing combinations of rennet concentration, coagulation temperature and post-coagulation curd cutting time were used, with comparisons made of the rheological and functional characteristics of cheeses during ageing. Lubricated squeezing flow, stress relaxation, melt and stretch measurements demonstrated that commercial LMPS Mozzarella had substantial textural and functional change between 7 and 30 days of age, while the rheological and functional behaviour of LMPS MF Mozzarella (MFM) exhibited substantial change between 30 and 60 days of age. Rennet concentration was the only experimental factor to significantly affect MFM rheological and functional development. The delayed development of MFM was partially attributed to inhibition of normal cheese proteolysis via whey protein (WP) incorporation, lack of starter culture protease, and homogenization of MF cheesemilk. Use of starter culture in MFM led to improved rheological and functional behaviour. [source] Probiotic characteristics of lactic acid bacteria isolated from kimchiJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2010J.-H. Chang Abstract Aims:, The present work was aimed at identifying strains of lactic acid bacteria (LAB) from kimchi, with properties suitable for use as starter cultures in yogurt fermentation. Methods and Results:, A total of 2344 LAB strains were obtained from two different sources, one group consisted of commercial LAB strains from kimchi, and the second group consisted of those strains isolated from various types of kimchi. The LAB strains from both groups were screened for resistance to biological barriers (acid and bile salts), and the four most promising strains were selected. Further analysis revealed that KFRI342 of the four selected strains displayed the greatest ability to reduce the growth of the cancer cells, SNU-C4. The in vivo efficacy of strains in quinone reductase induction assay was evaluated, and the extent of DNA strand breakage in individual cells was investigated using the comet assay. Strain KFRI342 was identified as Lactobacillus acidophilus by 16S rRNA sequence analysis, showed protection against tumour initiation and imparted immunostimulation as well as protection against DNA damage. Conclusions:, Strain KFRI342, which showed probiotic characteristics reducing cancer cell growth, could be a suitable starter culture for yogurt fermentation because of its strong acid production and high acid tolerance. Significance and Impact of the Study:, This is the first report to describe a bacterium, isolated from kimchi, Lact. acidophilus KFRI342 which has the probiotic characteristics and the acid tolerance needed for its use as a starter culture in yogurt fermentation. [source] Genotypic and technological characterization of Lactococcus lactis isolates involved in processing of artisanal Manchego cheeseJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2009P. Nieto-Arribas Abstract Aims:, Genotypic and technological characterization of wild lactococci isolated from artisanal Manchego cheese during the ripening process for selection of suitable starter cultures. Methods and Results:, A total of 114 isolates of lactococci were typed using randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Sixteen distinct RAPD-PCR patterns, at a similarity level of 73%, were obtained. On the basis of species-specific PCR reaction, the isolates were assigned to the species Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris with L. lactis subsp. lactis being predominant at both dairies. Twenty-six isolates were technologically characterized to select those with the best properties. Most of them showed good technological properties although some could produce tyramine. Conclusions:, The presence of coincident genotypes at both dairies has been demonstrated, which would suggest that they are well adapted to the Manchego cheese environment. Interesting differences were found in the technological characterization and the potential role of autochthonous lactococci strains as starter culture has been displayed. Significance and Impact of the Study:, The great economic importance of Manchego cheese encouraged a deeper knowledge of its microbiota, to select strains with the best properties to use as starter cultures in industrial Manchego cheeses, preserving the autochthonous characteristics. [source] Modelling the growth of Weissella cibaria as a function of fermentation conditionsJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2009A. Ricciardi Abstract Aims:, To investigate the effect of pH, water activity (aw) and temperature on the growth of Weissella cibaria DBPZ1006, a lactic acid bacterium isolated from sourdoughs. Methods and Results:, The kinetics of growth of W. cibaria DBPZ1006 was investigated during batch fermentations as a function of pH (4·0,8·0), aw (0·935,0·994) and temperature (10,45°C) in a rich medium. The growth curve parameters (lag time, growth rate and asymptote) were estimated using the dynamic model of Baranyi and Roberts (1994. A dynamic approach to predicting bacterial growth in food. Int J Food Microbiol23, 277,294). The effect of pH, aw and temperature on maximum specific growth rate (,max) were estimated by fitting a cardinal model. ,max under optimal conditions (pH = 6·6, aw = 0·994, T = 36·3°C) was estimated to be 0·93 h,1. Minimum and maximum estimated pH and temperature for growth were 3·6 and 8·15, and 9·0°C and 47·8°C, respectively, while minimum aw was 0·918 (equivalent to 12·2% w/v NaCl). Conclusions:,Weissella cibaria DBPZ1006 is a fast-growing heterofermentative strain, which could be used in a mixed starter culture for making bread. Significance and Impact of the Study:, This is the first study reporting the modelling of the growth of W. cibaria, a species that is increasingly being used as a starter in sourdough and vegetable fermentations. [source] Preliminary characterization of lactic acid bacteria isolated from Zlatar cheeseJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007K. Veljovic Abstract Aims:, Isolation, characterization and identification of lactic acid bacteria (LAB) from artisanal Zlatar cheese during the ripening process and selection of strains with good technological characteristics. Methods and Results:, Characterization of LAB was performed based on morphological, physiological and biochemical assays, as well as, by determining proteolytic activity and plasmid profile. rep-polymerase chain reaction (PCR) analysis and 16S rDNA sequencing were used for the identification of LAB. PCR analysis was performed with specific primers for detection of the gene encoding nisin production. Strains Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactobacillus brevis, Lactococcus lactis subsp. lactis, Enterococcus faecium and Enterococcus faecalis were the main groups present in the Zlatar cheese during ripening. Conclusions:, Temporal changes in the species were observed during the Zlatar cheese ripening. Mesophilic lactobacilli are predominant microflora in Zlatar cheese. Significance and Impact of the Study:, In this study we determined that Zlatar cheese up to 30 days old could be used as a source of strains for the preparation of potential starter cultures in the process of industrial cheese production. As the Serbian food market is adjusting to European Union regulations, the standardization of Zlatar cheese production by using starter culture(s) based on autochtonous well-characterized LAB will enable the industrial production of this popular cheese in the future. [source] Whey-cheese production using freeze-dried kefir culture as a starterJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2007D. Dimitrellou Abstract Aims:, The aim of the present study was to evaluate the use of a freeze-dried kefir culture in the production of a novel type of whey-cheese similar to traditional Greek Myzithra-cheese, to achieve improvement of the quality characteristics of the final product and the extension of shelf-life. Methods and Results:, The use of kefir culture as a starter led to increased lactic acid concentrations and decreased pH values in the final product compared with whey-cheese without starter culture. The effect of the starter culture on production of aroma-related compounds responsible for cheese flavour was also studied using the solid phase microextraction gas chromatography/mass spectrometry technique. Spoilage in unsalted kefir-whey-cheese was observed on the thirteenth and the twentieth day of preservation at 10 and 5°C, respectively, while the corresponding times for unsalted whey-cheese preservation were 11 and 14 days. Conclusions:, The cheeses produced were characterized as high-quality products during the preliminary sensory evaluation. An indication of increased preservation time was attributed to the freeze-dried kefir culture, which also seemed to suppress growth of pathogens. Significance and Impact of the Study:, The results suggested the use of kefir culture as a means to extend the shelf-life of dairy products with reduced or no salt content. [source] Inactivation of Staphylococcus aureus in raw milk cheese by combinations of high-pressure treatments and bacteriocin-producing lactic acid bacteriaJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2005J.L. Arqués Abstract Aims:, To investigate the combined effect of high-pressure treatments (HPT) and milk inoculation with bacteriocin-producing lactic acid bacteria (BP-LAB) on the survival of Staphylococcus aureus during ripening of raw milk cheese. Methods and Results:, Cheeses were manufactured from raw milk artificially contaminated with S. aureus at ca 5 log CFU ml,1, a commercial starter culture and one of seven strains of BP-LAB, added as adjuncts at 0·1%. HPT of cheeses were performed on days 2 or 50 at 300 MPa (10°C, 10 min) or 500 MPa (10°C, 5 min). On day 3, S. aureus counts were 6·46 log CFU g,1 in control cheese. Milk inoculation with different BP-LAB lowered S. aureus counts on day 3 when compared with control cheese by up to 0·46 log CFU g,1, HPT at 300 MPa on day 2 by 0·45 log CFU g,1 and HPT at 500 MPa on day 2 by 2·43 log CFU g,1. Combinations of BP-LAB with HPT at 300 and 500 MPa on day 2 lowered S. aureus counts on day 3 by up to 1·02 and 4·00 log CFU g,1 respectively. Conclusions:, The combined effect of milk inoculation with some of the BP-LAB tested and HPT of cheese on S. aureus inactivation was synergistic. Significance and Impact of the Study:, The combination of HPT at lower pressures with BP-LAB inoculation is a feasible system to improve cheese safety in case of deleterious effects on cheese quality caused by HPT at higher pressures. [source] DETERMINATION OF pH CHANGE KINETICS DURING DIFFERENT STAGES OF KASHAR CHEESE MANUFACTURING FROM RAW AND PASTEURIZED MILK WITH ADDITION OF THERMOPHILIC, MESOPHILIC AND MIXED THERMOPHILIC CULTUREJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2008AHMET FERIT ATASOY ABSTRACT The pH change kinetics during Kashar cheese production from raw and pasteurized milk with addition of thermophilic, mesophilic and mixed thermophilic-mesophilic lactic acid bacteria were evaluated. The kinetics of pH change were determined during milk ripening, cooking/holding and pressing/fermentation phases of Kashar cheese. The pH decreased logarithmically, nonlinearly, with time in the milk ripening period, and reduced linearly with time in the cooking/holding and pressing/fermentation stages. Pasteurization of milk retarded the rate of change in pH during the three periods. The highest rate of pH change was determined in the addition of thermophilic culture, followed by mixed thermophilic-mesophilic and then mesophilic ones during milk ripening. The pH change characteristics of cheese made with thermophilic starter were similar to the cheese made with mixed thermophilic-mesophilic culture, but different from mesophilic lactic acid bacteria during cooking/holding and pressing/fermentation stages. PRACTICAL APPLICATIONS One of the important factors in the control of cheese quality is the extent of acid production in the vat. Acid development at a desired rate is important during cheese making. The progress of acidification is monitored by pH change in the industrial Kashar cheese production. Three main stages have been recognized with respect to pH change: milk ripening, cooking/holding and pressing/fermentation. This study evaluated and compared the pH change kinetics during various stages of Kashar cheese making using raw, pasteurized milk with the addition of thermophilic, mesophilic and mixed thermophilic culture. This work may help in the comparison of raw and pasteurized milk, and in the selection of appropriate starter culture for Kashar cheese production. [source] EFFECT OF LACTIC ACID FERMENTATION OF CASSAVA ON FUNCTIONAL AND SENSORY CHARACTERISTICS OF FUFU FLOURJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2008A.O. SOBOWALE ABSTRACT The effects of lactic acid fermentation of cassava on the functional and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96 h. The resultant wet fufu samples were dried at 65C in a cabinet dryer for 48 h, and were analyzed for functional and sensory characteristics. Fermentation reduced the water-binding capacity of the fufu flour from 176.6% to between 118 and 125%. The pasting characteristics of the traditional and starter culture-fermented fufu flour samples were not significantly different from that of the unfermented cassava flour. When subjected to sensory evaluation, the traditional and starter culture-fermented cassava fufu flour were not significantly different in terms of color, odor and texture, but the cassava fufu flour produced, using starter culture SL19, had the highest overall acceptability (P < 0.05). PRACTICAL APPLICATIONS Traditionally, processing of cassava to fufu is usually carried out by using the old stock from a previous fermentation to initiate the fermentation of a new batch. This old method usually results in fufu that has a strong odor that may not be acceptable to some consumers. The use of starter culture like Lactobacillus plantarum will reduce the strong odor of fufu; this will increase its acceptability by consumers and ensure the overall quality. Also, the functional properties of fufu are not affected. The development of lactobacilli strains could help in optimizing the traditional processes, therefore increasing the economic returns. [source] PROTECTIVE CULTURES USED FOR THE BIOPRESERVATION OF HORSE MEAT FERMENTED SAUSAGE: MICROBIAL AND PHYSICOCHEMICAL CHARACTERIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2008JAZILA EL MALTI ABSTRACT In this paper, 150 isolates, originating from horse meat, were subjected to step-by-step screening and characterization to search for potential protective cultures to be used in the meat industry. Isolates were first tested on their homofermentative and salt tolerance. Second, the antibacterial capacities toward Listeria monocytogenes were determined in an agar spot test. In total, 50% of the tested isolates were inhibitory toward Listeria monocytogenes. However, only 12 isolates produced a bacteriocin. Finally, three isolates with the strong bacteriocin activity were evaluated on their competitive nature by comparing their growth rate, acidifying character and lactic acid production at 15C under anaerobic conditions in a liquid broth. All three isolates combined a fast growth rate with a deep and rapid acidification caused by the production of high levels of lactic acid. Lactobacillus sakei was used as starter culture for producing sausage horse meat. In this study, fermentations were followed analyzing the microbiological and physicochemical aspects of this product. The sausages were characterized by an important microbial activity of lactic acid bacteria that resulted in a product with a final pH of about 4.56. No Listeria monocytogenes, Salmonella spp. or sulfite reducing clostridia were ever isolated from the raw materials or the fermented sausages during the maturation, underlining the microbial safety of this product. The final water activity of the product was 0.85. Starter cultures showed that Lactobacillus sakei was really efficient in reducing the amine production since this strain caused a quick pH drop during sausage fermentation. PRACTICAL APPLICATIONS A starter culture can be defined as a microbial preparation of large numbers of cells of at least one microorganism to be added to a raw material to produce a fermented food by accelerating and steering its fermentation process. The group of lactic acid bacteria (LAB) occupies a central role in these processes, and has a long and safe history of application and consumption in the production of fermented foods and beverages. They cause rapid acidification of the raw material through the production of organic acids, mainly lactic acid. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides and several enzymes is of importance. The main reason for suitability of LAB is their natural origin, and they can contribute to food safety and/or offer one or more organoleptic, technological, nutritional or health advantages. [source] EFFECT OF THERMOPHILIC LACTIC ACID BACTERIA ON THE FATE OF ENTEROBACTER SAKAZAKII DURING PROCESSING AND STORAGE OF PLAIN YOGURTJOURNAL OF FOOD SAFETY, Issue 2 2008REYAD R. SHAKER ABSTRACT Survival and growth of Enterobacter sakazakii during processing and storage of plain yogurt were investigated. Preheated rehydrated milk was inoculated with a cocktail culture of E. sakazakii (103 cfu/mL of milk) and/or with thermophilic yogurt starter culture of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus salivarius ssp. thermophilus. The inoculated milk was incubated at 40C for 5 h, then the samples were cooled and subsequently stored at 4C for up to 7 days. The results showed that E. sakazakii grew at an early stage of fermentation but declined at the end of the process. There was no significant difference between the populations of E. sakazakii in the presence or absence of lactic acid bacteria during the first 4 h of the incubation period but there was significant difference during the last hour of the incubation period. The populations of E. sakazakii decreased significantly during cooling and storage of yogurt (pH 4.2,4.7) compared with nonfermented milk samples at 4C. The presence of E. sakazakii did not have a significant effect on the growth of LAB during fermentation and storage of yogurt. The results obtained from this study indicate that the pH of yogurt and storage temperature were critical to the survival and growth of E. sakazakii in the manufacture of plain yogurt. PRACTICAL APPLICATIONS Enterobacter sakazakii prevalence in milk products and the production environment has been documented. The results obtained from this study may be of use to dairy producers to manufacture safe products using thermophilic lactic acid bacteria. These bacteria decreased the pH of milk in less than 5 h, resulting in E. sakazakii reduction. pH of yogurt during the fermentation process is a critical control point that should be monitored to produce safe products. [source] ACID PH PRODUCED BY LACTIC ACID BACTERIA PREVENT THE GROWTH OF BACILLUS CEREUS IN BOZA, A TRADITIONAL FERMENTED TURKISH BEVERAGEJOURNAL OF FOOD SAFETY, Issue 2 2005KIYMET GÜVEN ABSTRACT The growth and survival of Bacillus cereus, a known pathogen commonly found in cereals, during lactic acid fermentation of boza, a traditional Turkish cereal beverage, was studied. In the boza base inoculated with both the starter culture and B. cereus, the acidity developed to pH 2.6 and 0.8% titratable acidity after 72 h; the growth of B. cereus was reduced from 3.9 log cfu/mL to 1 log cfu/mL within 72 h. The control boza base to which starter was not added had a pH of 3, titratable acidity of 0.8%. The B. cereus in this boza base to which no starter culture was added dropped to 1 log cfu/mL after 72 h. No strains of lactic acid bacteria were found to produce bacteriocins antagonistic to B. cereus. Low pH and acidity were found to be the major factors inhibiting growth of B. cereus in boza. [source] Effects of Leuconostoc mesenteroides Starter Culture on Fermentation of Cabbage with Reduced Salt ConcentrationsJOURNAL OF FOOD SCIENCE, Issue 5 2007Suzanne Johanningsmeier ABSTRACT:, Sauerkraut fermentations rely upon selection of naturally occurring lactic acid bacteria by addition of 2.0% to 2.25% granulated sodium chloride (NaCl) to shredded cabbage. Excess brine generated is a waste product with high levels of organic material (BOD) and nonbiodegradable NaCl. The objective was to determine whether addition of Leuconostoc mesenteroides starter culture to reduced-salt cabbage fermentations would yield sauerkraut with reproducible and acceptable chemical composition and sensory qualities. Shredded cabbage was salted with 0.5%, 1.0%, or 2.0% NaCl (wt/wt) at 2 starter culture levels, none or L. mesenteroides strain LA 81, ATCC 8293 (106 CFU/g). Fermentation products were quantified by high-performance liquid chromatography, and pH was measured during the initial stages of fermentation and after 10 mo storage at 18 °C. A trained descriptive sensory panel used category scales to rate the flavor and texture of selected sauerkrauts. A modified Kramer shear test was used to measure firmness. Cabbage fermented with L. mesenteroides consistently resulted in sauerkraut with firm texture and reduced off-flavors across all salt levels (P < 0.05). Conversely, sauerkraut quality was highly variable, with softening and off-flavors occurring as salt concentrations were decreased in natural fermentations (P < 0.05). Fermentations were rapid, with a more uniform decline in pH when starter culture was added. L. mesenteroides addition to cabbage fermentations ensured that texture and flavor quality were retained, while allowing 50% NaCl reduction. Application of this technology to commercial sauerkraut production could improve the uniformity of fermentations and substantially reduce generation of nonbiodegradable chloride waste. [source] Probiotic Strains as Starter Cultures Improve Angiotensin-converting Enzyme Inhibitory Activity in Soy YogurtJOURNAL OF FOOD SCIENCE, Issue 8 2005O.N. Donkor ABSTRACT Suitability of soy yogurt as a system for delivering probiotics and other bioactive compounds was assessed by fermenting soy milk using starter culture containing Lactobacillus delbrueckii ssp. bulgaricus Lb1466, Streptococcus thermophilus St1342, and probiotic organisms (Lactobacillus acidophilus LAFTI® L10, Bifidobacterium lactis LAFTI® B94, and Lactobacillus paracasei LAFTI® L26). Fermentations were terminated at different pH of 4.50, 4.55, and 4.60 and metabolic patterns of cultures (viability, proteolytic activity, organic acids production, angiotensin-converting enzyme (ACE) inhibitory activity) were investigated during 28 d of storage at 4 °C. The presence of probiotics enhanced the growth of L. delbrueckii ssp. bulgaricus Lb1466 and S. thermophilus St134 in soy yogurt in comparison to the control produced by sole yogurt culture. In general, different termination pH had no effect (P > 0.05) on the viability of probiotic organisms that maintained good viability in soy yogurt during cold storage. Higher levels of essential growth factors in the form of peptides and amino acids in soy yogurts may have promoted the growth of L. acidophilus LAFTI® L10, B. lactis LAFTI® B94, and L. paracasei LAFTI® L26. The use of probiotic strains as a part of starter culture in soy yogurt resulted in a substantial increase in in vitro ACE inhibitory activity compared with the control produced by yogurt culture only. This improvement of ACE inhibition in soy yogurt is partly due to higher proteolytic activity of probiotics. [source] Differential Glucose and Fructose Utilization During Cucumber Juice FermentationJOURNAL OF FOOD SCIENCE, Issue 1 2001Z. Lu ABSTRACT: Glucose (32 mM) and fructose (36mM) of cucumber juice were degraded simultaneously by Lactobacillus plantarum, but at different rates and extents. Glucose depletion was slightly more rapid than fructose during the exponential growth phase, but slower thereafter and stopped before exhaustion. In contrast, fructose degradation continued until all naturally present fructose was exhausted. When cucumber juice was supplemented with fructose and/or glucose, the starter culture continued to ferment fructose, but not glucose, resulting in an increase in lactic acid production and a decrease in terminal pH. Fructose utilization was not affected by the presence of glucose, but the presence of fructose reduced glucose utilization. [source] EFFECT OF COLD STORAGE ON CULTURE VIABILITY AND SOME RHEOLOGICAL PROPERTIES OF FERMENTED MILK PREPARED WITH YOGURT AND PROBIOTIC BACTERIAJOURNAL OF TEXTURE STUDIES, Issue 1 2008MARIA REGINA DAMIN ABSTRACT We examined the effect of storage time on culture viability and some rheological properties (yield stress, storage modulus, loss modulus, linear viscoelastic region, structural recuperation and firmness) of fermented milk made with Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus (LA) and Bifidobacterium animalis ssp. lactis in coculture with Streptococcus thermophilus (ST). Acidification profiles and factors that affect viability (postfermentation acidification, acidity and dissolved oxygen) were also studied during 35 days at 4C. Fermented milk prepared with a coculture of ST and Bifidobacterium lactis gave the most constant rheological behavior and the best cell viability during cold storage; it was superior to ST plus LA for probiotic fermented milk production. PRACTICAL APPLICATIONS Probiotic cultures should grow quickly in milk, provide adequate sensory and rheological properties to the product, and remain viable during storage. Commercially, it is very common to use yogurt starter culture (i.e. Streptococcus thermophilus[ST] and Lactobacillus delbrueckii ssp. bulgaricus) in combination with the probiotic bacteria in order to reduce fermentation time. However, LB tends to post acidify fermented milk, which reduces the viability of the probiotic bacteria; thus, it is recommended to use starter cultures devoid of this species. We found that the technological properties and the viability of the probiotic bacterium Bifidobacterium animalis ssp. lactis BL O4 in coculture with ST make it suitable for probiotic fermented milk production; it produces rheological characteristics similar to those of yogurt. [source] Use of a lactic acid bacteria starter culture during green olive (Olea europaea L cv Ascolana tenera) processingJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2005Vincenzo Marsilio Abstract Among the Italian olive germplasm, ,Ascolana tenera' is one of the best varieties for table olive production. This research addressed the impact of different processing types (Greek-style and Spanish-style) on the fermentation and phenolic composition of olive fruit. In particular, the effects of a lactic acid bacteria (LAB) starter culture on the fermentation of naturally green olives processed according to the traditional Greek method were studied. Results revealed that Spanish-style processing produced a dramatic loss of total phenolics, while natural olive processing favoured a higher retention of biophenols. Oleoside 11-methylester, a phenol-related compound, and hydroxytyrosol, tyrosol, vanillic acid, 3,4-dihydroxyphenylglycol, oleuropein and oleuropein aglycons, as the main phenols, were detected in olive fruit. More interestingly, this research indicated that inoculation with LAB affected the pH, total acidity, microbial profile and palatability of olives. Olives fermented with the LAB starter culture were perceived by panellists to be less bitter and more aromatic than those spontaneously fermented. Thus the use of LAB inoculants during olive fermentation could be applied with the currently available technology. Copyright © 2005 Society of Chemical Industry [source] The influence of pre-fermentative practices on the dominance of inoculated yeast starter under industrial conditionsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2002Maurizio Ciani Abstract The influence of pre-fermentative practices on the growth dynamics of a ,natural' starter culture with specific phenotype (H2S,) concurrently with wild yeast populations was evaluated under winery conditions. Different clarification procedures and added SO2 strongly influenced species and cell numbers isolable at the pre-fermentation stage. Independent treatments of must with sulphite addition or vacuum-filtering clarification caused a 30-fold reduction in viable cells. Clarification procedures, enhanced by the selective effect of SO2 addition, induced the appearance of Saccharomyces cerevisiae ,wild' yeasts. Correct application of the inoculum generally guarantees the dominance of fermentation by starter cultures. However, inoculated fermentations using unclarified white and red musts exhibited a consistent presence and persistence of non- Saccharomyces and/or Saccharomyces ,wild' yeasts during fermentation. The extent and composition of the initial wild microflora at the start of fermentation may affect the presence and persistence of wild Saccharomyces and non- Saccharomyces yeasts during guided fermentations under commercial conditions. The above findings confirm the results of previous works carried out at laboratory- or pilot-scale level. Furthermore, they suggest a clear correlation between the modality of pre-fermentative practices and the presence and persistence of ,wild' yeasts during fermentation. © 2002 Society of Chemical Industry [source] Influence of heat impact in reconstituted skim milk on the properties of yoghurt fermented by ropy or non-ropy starter culturesMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 5 2003Peter Chr. Abstract The paper describes studies on the influence of heat impact in reconstituted skim milk on chemical and functional properties of yoghurt products. Reconstituted skim milk was heated for 20 min at 85°C, 90°C, or 95°C. Ropy (producing exopolysaccharides, EPS) or non-ropy strains of S. thermophilus and L. delbrueckii subsp. bulgaricus were used as starter culture for yoghurt manufacture. The studies have shown that the fermentation times decreased with increasing heat impact when the ropy starter culture was used, while they remained to a far extent unchanged if the non-ropy starter culture was applied. The lactic acid contents of the yoghurt products were in the same range when the milk was heated at 85°C or 90°C, while they were different when milk was heated at 95°C. There was a tendency visible that an increase in preheating leads to increased L(+)- and decreased D(,)-lactic acid contents if the non-ropy culture was applied. Using the ropy culture, it was vice versa. A slightly decrease in proteolysis with increasing heat impact was to be noted with both starter cultures. Concerning the relation of proteolysis to acidification, the fermentation process could be subdivided into three sections with different slopes if the non-ropy starter culture was used, while a linear relation was found if the ropy starter culture was applied. Regarding final product characteristics it was found that the functional properties of yoghurt decreased with increasing heat impact when the ropy starter culture was applied, while they remained to a far extent unchanged when the non-ropy starter culture was used. It can be concluded from these studies that a preheating of milk at a temperature of 85°C (20 min) is optimal in regard to final yoghurt product characteristics. [source] Identification of a potent immunostimulatory oligodeoxynucleotide from Streptococcus thermophilus lacZANIMAL SCIENCE JOURNAL, Issue 5 2009Takeshi SHIMOSATO ABSTRACT Immunostimulatory sequences of oligodeoxynucleotides (ODNs), such as CpG ODNs, are potent stimulators of innate immunity. Here, we identified a strong immunostimulatory CpG ODN, which we named MsST, from the lac Z gene of Streptococcus (S.) thermophilus ATCC19258, and we evaluated its immune functions. In in vitro studies, MsST had a similar ability as the murine prototype CpG ODN 1555 to induce inflammatory cytokine production and cell proliferation. In mouse splenocytes, MsST increased the number of CD80+CD11c+and CD86+CD11c+ dendritic cells and CD4+CD25+ regulatory T cells. We also analyzed the effects of MsST on the expression of regulatory cytokines by real-time quantitative PCR. MsST was more potent at inducing interleukin-10 expression than the ODN control 1612, indicating that MsST can augment the regulatory T cell response via Toll-like receptor 9, which plays an important role in suppressing T helper type 2 responses. These results suggest that S. thermophilus, whose genes include a strong Immunostimulatory sequence-ODN, is a good candidate for a starter culture to develop new physiologically functional foods and feeds. [source] Biotransformation of tuna waste by co-fermentation into an aquafeed ingredientAQUACULTURE RESEARCH, Issue 9 2009Hena Vijayan Abstract Dried skipjack tuna (Katsuwonus pelamis) waste (red meat, gills, viscera, fins, etc.) were mixed with 25% wheat flour and inoculated with a starter culture of Lactobacillus plantarum National Collection of Industrial Microorganisms (NCIM) 2912 (108,109 cells mL,1) and Bacillus licheniformis MTCC 6824 (107,108 cells mL,1). Changes in the nutritional quality (crude protein, crude fat, crude ash, crude fibre and nitrogen-free extract and aminoacids) were monitored during a fermentation period of 14 days. The proximate analysis showed significant changes in the composition of L. plantarum -fermented tuna (LPFT) and B. licheniformis -fermented tuna (BLFT) from the unfermented raw materials. Fermentation of tuna waste has resulted in a significant (P<0.05) increase in the protein content of tuna waste between days 6 and 12. All the amino acid contents in BLFT increased during fermentation, whereas, in LPFT the levels of serine, histidine, tyrosine, methionine, cystine and phenylalanine contents were decreased. A marginal increase in calcium and phosphorus levels was recorded in the fermented products. The results of the study suggest that LPFT or BLFT can be used as a novel aquafeed ingredient for different fish species. [source] Flavour formation by lactic acid bacteria and biochemical flavour profiling of cheese productsFEMS MICROBIOLOGY REVIEWS, Issue 3 2005Gerrit Smit Abstract Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which the starter cultures provide the enzymes. Particularly the enzymatic degradation of proteins (caseins) leads to the formation of key-flavour components, which contribute to the sensory perception of dairy products. More specifically, caseins are degraded into peptides and amino acids and the latter are major precursors for volatile aroma compounds. In particular, the conversion of methionine, the aromatic and the branched-chain amino acids are crucial. A lot of research has focused on the degradation of caseins into peptides and free amino acids, and more recently, enzymes involved in the conversion of amino acids were identified. Most data are generated on Lactococcus lactis, which is the predominant organism in starter cultures used for cheese-making, but also Lactobacillus, Streptococcus, Propionibacterium and species used for surface ripening of cheeses are characterised in their flavour-forming capacity. In this paper, various enzymes and pathways involved in flavour formation will be highlighted and the impact of these findings for the development of industrial starter cultures will be discussed. [source] Effect of addition of amino acids, treatment with ,-galactosidase and use of heat-shocked cultures on the acetaldehyde level in yoghurtINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2002Barbaros Özer In this study, the biochemical activities of nonviscous and viscous yoghurt starter cultures were investigated. Yoghurt samples produced with nonviscous and viscous cultures, and viscous cultures + methionine (10 and 30 mg/100 mL milk), + threonine (5 and 10 mg/100 mL milk), + ,-galactosidase (1 mg/100 mL milk), and with a heat-shocked culture were analysed. In the experimental yoghurts, the pH, titratable acidity, lactic acid, tyrosine and acetaldehyde contents and the number of total starter organisms were determined. According to the results obtained, the samples produced with the viscous culture had the lowest acetaldehyde levels, whereas the highest acetaldehyde level was found in the samples manufactured with the nonviscous culture. Compared with the samples inoculated with the viscous culture alone, the amino acid supplementation, lactose hydrolysis and heat-shock treatments caused a significant increase in the level of acetaldehyde. [source] Combined use of bacteriocin-producing strains to control Listeria monocytogenes regrowth in raw pork meatINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2010Privat Kouakou Summary Avoiding the presence of Listeria in meat and dairy products is a major challenge for the food industry. In this work, a Lactobacillus curvatus strain producing the bacteriocin sakacin P and a Pediococcus acidilactici strain producing another bacteriocin, pediocin AcH, were used as starter cultures under laboratory conditions in a Listeria -seeded raw-pork-meat matrix, which was then stored for 6 weeks at 4 °C. At 1 week intervals during the storage period, the antilisterial activity was evaluated. When either strain was added alone, the Listeria monocytogenes cfu count initially dropped from 102 cfu g,1 to an undetectable level by the end of week 1 or 2, but this was followed by a rebound (regrowth) 1 week later. When both strains were added together to the meat matrix, rebound was delayed, Listeria remaining undetected from the end of week 1 to the end of week 5. A rebound was observed 6 weeks post-inoculation, but fewer than 10 cfu g,1 were counted. The use of more than one bacteriocin-producing strain may thus overcome some of the problems limiting the effectiveness of bacteriocins in food systems. [source] | |||||||||||||