Bacteriophage ecology in commercial sauerkraut fermentations

Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60- or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.     

Bacteriophage Ecology in Commercial Sauerkraut Fermentations

Knowledge of bacteriophage ecology in vegetable fermentations is essential for developing phage control strategies for consistent and high quality of fermented vegetable products. The ecology of phages infecting lactic acid bacteria (LAB) in commercial sauerkraut fermentations was investigated. Brine samples were taken from four commercial sauerkraut fermentation tanks over a 60- or 100-day period in 2000 and 2001. A total of 171 phage isolates, including at least 26 distinct phages, were obtained. In addition, 28 distinct host strains were isolated and identified as LAB by restriction analysis of the intergenic transcribed spacer region and 16S rRNA sequence analysis. These host strains included Leuconostoc, Weissella, and Lactobacillus species. It was found that there were two phage-host systems in the fermentations corresponding to the population shift from heterofermentative to homofermentative LAB between 3 and 7 days after the start of the fermentations. The data suggested that phages may play an important role in the microbial ecology and succession of LAB species in vegetable fermentations. Eight phage isolates, which were independently obtained two or more times, were further characterized. They belonged to the family Myoviridae or Siphoviridae and showed distinct host ranges and DNA fingerprints. Two of the phage isolates were found to be capable of infecting two Lactobacillus species. The results from this study demonstrated for the first time the complex phage ecology present in commercial sauerkraut fermentations, providing new insights into the bioprocess of vegetable fermentations.     

Fermentation of philippine vegetable blends

Seven blends of Philipphine vegetables, two of which contained soybeans and one mongo bean sprouts, were prepared for fermentation and study of microbiological and chemical changes. The fermentations were typical lactic acid bacterial fermentations, initiated by Leuconostoc mesenteroides and continued by Lactobacillus brevis, Pediococcus cerevisiae, and L. plantarum. The combination of high acidity and low pH resembled other vegetable fermentations, such as sauerkraut. The procedure offers a method of preserving surplus vegetables, and, in addition, a method for incorporating and preserving the high-protein-containing soybeans.     

Fermentation of the Yugoslavian Pickled Cabbage

In Yugoslavia, cabbage is preserved by fermentation using a variety of methods. Bacteriological study of these fermentations has shown that the relative influence of the various lactic acid producing bacteria varies somewhat with the method of preservation. The heterofermenters, Leuconostoc mesenteroides and Lactobacillus brevis, exert a greater effect when cabbage is shredded than when the whole heads are packed in salt brine. Whole heads of cabbage preserved by fermentation in salt brine are a good source of ascorbic acid and provide a flavorful food.     

Isolation and Characterization of Bacteriophages from Fermenting Sauerkraut

This paper presents the first report of bacteriophage isolated from commercial vegetable fermentations. Nine phages were isolated from two 90-ton commercial sauerkraut fermentations. These phages were active against fermentation isolates and selected Leuconostoc mesenteroides and Lactobacillus plantarum strains, including a starter culture. Phages were characterized as members of the Siphoviridae and Myoviridae families. All Leuconostoc phages reported previously, primarily of dairy origin, belonged to the Siphoviridae family.     

Phenotypic and genotypic analyses of lactic acid bacteria in local fermented food, breast milk and faeces of mothers and their babies

Lactic acid bacteria (LAB) are generally accepted as beneficial to the host and their presence is directly influenced by ingestion of fermented food or probiotics. While the intestinal lactic microbiota is well-described knowledge on its routes of inoculation and competitiveness towards selective pressure shaping the intestinal microbiota is limited. In this study, LAB were isolated from faecal samples of breast feeding mothers living in Syria, from faeces of their infants, from breast milk as well as from fermented food, typically consumed in Syria. A total of 700 isolates were characterized by genetic fingerprinting with random amplified polymorphic DNA (RAPD) and identified by comparative 16S rDNA sequencing and Matrix Assisted Laser Desorption Ionization-Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS) analyses. Thirty six different species of Lactobacillus, Enterococcus, Streptococcus, Weissella and Pediococcus were identified. RAPD and MALDI-TOF-MS patterns allowed comparison of the lactic microbiota on species and strain level. Whereas some species were unique for one source, Lactobacillus plantarum, Lactobacillus fermentum, Pediococcus pentosaceus and Lactobacillus brevis were found in all sources. Interestingly, identical RAPD genotypes of L. plantarum, L. fermentum, L. brevis, Enterococcus faecium, Enterococcus faecalis and P. pentosaceus were found in the faeces of mothers, her milk and in faeces of her babies. Diversity of RAPD types found in food versus human samples suggests the importance of host factors in colonization and individual host specificity, and support the hypothesis that there is a vertical transfer of intestinal LAB from the mother's gut to her milk and through the milk to the infant's gut.     

Isolation and characterization of lactic acid bacteria from yan-taozih (pickled peaches) in Taiwan

Two hundred cultures of lactic acid bacteria were isolated from eight yan-taozih (pickled peaches) samples, and four cultures were isolated from the main component of these samples, fresh peaches. Phenotypic and biochemical characteristics identified eight different bacterial groups (A–H) and showed that the majority of the isolates was heterofermentative lactic acid bacteria. The most common bacterial species in yan-taozih was Leuconostoc mesenteroides, although regional diversity was also observed among the lactic acid bacteria strains isolated. The antibacterial activities of the isolates were also determined, and 20 isolates were found to show inhibitory activity against the indicator strain Lactobacillus sakei JCM 1157^T. The results of the sensory evaluation suggested that the diversity of lactic acid bacteria has a great effect on the aroma and formation of taste in the food product. Our findings suggest that Leuconostoc mesenteroides is the most abundant lactic acid bacteria in yan-taozih (pickled peaches) and that lactic acid bacteria strains play an important role in affecting the aroma and taste of the food product.     

Flour carbohydrate catabolism and metabolite production by sourdough lactic acid bacteria

The aim of this study was to assess the mode of carbohydrate catabolism by lactic acid bacteria isolated from traditional sourdoughs, as well as to study their effect on the metabolites produced. For this purpose, single cultures of the heterofermentative lactic acid bacteria Lactobacillus sanfranciscensis, Lactobacillus brevis, Weissella cibaria, and the homofermentative Lactobacillus paralimentarius and Pediococcus pentosaceus were grown in liquid media containing glucose, fructose, maltose and sucrose, either as a single carbon source or in combination with glucose. Carbon catabolism and the production of metabolites were determined by HPLC analysis. W. cibaria could ferment all carbon sources, L. sanfranciscensis, L. paralimentarius and P. pentosaceus could not ferment sucrose, while L. brevis could only ferment maltose. The presence of glucose did not influence the utilization of fructose and maltose by L. sanfranciscensis, while it repressed the fermentation of fructose, maltose and sucrose by W. cibaria, and fructose and maltose by L. paralimentarius and P. pentosaceus. Moreover, L. sanfranciscensis and L. brevis could obtain extra ATP through the reduction of fructose to mannitol, which favored the production of acetic acid against ethanol. The utilization of fructose as an electron acceptor has a decisive effect on the prevailing of L. sanfranciscensis and L. brevis in spontaneously fermented sourdough and in the scarce appearance of the other lactic acid bacteria studied.     

Bloater Formation by Gas-forming Lactic Acid Bacteria in Cucumber Fermentations

The formation of “bloaters” (hollow stock) in cucumbers brined for salt-stock purposes at 5 to 10% salt has been associated with gaseous fermentation caused chiefly by yeasts. Recently, serious early bloater damage, not attributable to yeasts, has been observed in commercial-scale experiments on control of bloaters in overnight dill pickles brined in 50-gal barrels at 3.0 to 4.5% salt. Growth of fermentative species of yeasts was effectively controlled by the addition of 0.025, 0.05, and 0.1% sorbic acid or its sodium salt. In contrast to this, the fermenting brines showed extremely high populations of acid-forming bacteria, identified as Lactobacillus plantarum, L. brevis, and Pediococcus cerevisiae. The gas-forming species (i.e., L. brevis) constituted a high proportion of the total populations. Representative isolates from 36 barrels of overnight dill pickles were tested for their ability to produce bloaters in 1-quart jars of pasteurized cucumbers equilibrated at 4 to 5% salt, 0.25% lactic acid, and pH 4.0. Bloaters, identical with those made by yeast cultures, were produced in all jars inoculated with L. brevis. No bloaters were produced by L. plantarum and P. cerevisiae. These results suggest that the control of bloater damage in cucumber fermentations, particularly at low salt concentrations, may necessitate inhibition of gas-forming lactic acid bacteria.     

Microbiological Study of Lactic Acid Fermentation of Caper Berries by Molecular and Culture-Dependent Methods

Fermentation of capers (the fruits of Capparis sp.) was studied by molecular and culture-independent methods. A lactic acid fermentation occurred following immersion of caper berries in water, resulting in fast acidification and development of the organoleptic properties typical of this fermented food. A collection of 133 isolates obtained at different times of fermentation was reduced to 75 after randomly amplified polymorphic DNA (RAPD)-PCR analysis. Isolates were identified by PCR or 16S rRNA gene sequencing as Lactobacillus plantarum (37 isolates), Lactobacillus paraplantarum (1 isolate), Lactobacillus pentosus (5 isolates), Lactobacillus brevis (9 isolates), Lactobacillus fermentum (6 isolates), Pediococcus pentosaceus (14 isolates), Pediococcus acidilactici (1 isolate), and Enterococcus faecium (2 isolates). Cluster analysis of RAPD-PCR patterns revealed a high degree of diversity among lactobacilli (with four major groups and five subgroups), while pediococci clustered in two closely related groups. A culture-independent analysis of fermentation samples by temporal temperature gradient electrophoresis (TTGE) also indicated that L. plantarum is the predominant species in this fermentation, in agreement with culture-dependent results. The distribution of L. brevis and L. fermentum in samples was also determined by TTGE, but identification of Pediococcus at the species level was not possible. TTGE also allowed a more precise estimation of the distribution of E. faecium, and the detection of Enterococcus casseliflavus (which was not revealed by the culture-dependent analysis). Results from this study indicate that complementary data from molecular and culture-dependent analysis provide a more accurate determination of the microbial community dynamics during caper fermentation.     

Detection of Lactobacillus, Pediococcus, Leuconostoc, and Weissella Species in Human Feces by Using Group-Specific PCR Primers and Denaturing Gradient Gel Electrophoresis

Denaturing gradient gel electrophoresis (DGGE) of DNA fragments generated by PCR with 16S ribosomal DNA-targeted group-specific primers was used to detect lactic acid bacteria (LAB) of the genera Lactobacillus, Pediococcus, Leuconostoc, and Weissella in human feces. Analysis of fecal samples of four subjects revealed individual profiles of DNA fragments originating not only from species that have been described as intestinal inhabitants but also from characteristically food-associated bacteria such as Lactobacillus sakei, Lactobacillus curvatus, Leuconostoc mesenteroides, and Pediococcus pentosaceus. Comparison of PCR-DGGE results with those of bacteriological culture showed that the food-associated species could not be cultured from the fecal samples by plating on Rogosa agar. On the other hand, all of the LAB species cultured from feces were detected in the DGGE profile. We also detected changes in the types of LAB present in human feces during consumption of a milk product containing the probiotic strain Lactobacillus rhamnosus DR20. The analysis of fecal samples from two subjects taken before, during, and after administration of the probiotic revealed that L. rhamnosus was detectable by PCR-DGGE during the test period in the feces of both subjects, whereas it was detectable by culture in only one of the subjects.     

Presence of erythromycin and tetracycline resistance genes in lactic acid bacteria from fermented foods of Indian origin

Lactic acid bacteria (LAB) resistant to erythromycin were isolated from different food samples on selective media. The isolates were identified as Enterococcus durans, Enterococcus faecium, Enterococcus lactis, Enterococcus casseliflavus, Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus fermentum, Pediococcus pentosaceus and Leuconostoc mesenteroides. Of the total 60 isolates, 88 % harbored the ermB gene. The efflux gene msrA was identified in E. faecium, E. durans, E. lactis, E. casseliflavus, P. pentosaceus and L. fermentum. Further analysis of the msrA gene by sequencing suggested its homology to msrC. Resistance to tetracycline due to the genes tetM, tetW, tetO, tetK and tetL, alone or in combination, were identified in Lactobacillus species. The tetracycline efflux genes tetK and tetL occurred in P. pentosaceus and Enterococcus species. Since it appeared that LAB had acquired these genes, fermented foods may be a source of antibiotic resistance.     

Use of autochthonous lactic acid bacteria starters to ferment mango juice for promoting its probiotic roles

Strains of Leuconostoc mesenteroides, Pediococcus pentosaceus, and Lactobacillus brevis were identified from mango fruits by partial 16S rDNA gene sequence. Based on the ability of producing mannitol and diacetyl, Leuconostoc mesenteroides MPL18 and MPL39 were selected within the lactic acid bacteria isolates, and used as mixed starters to ferment mango juice (MJ). Both the autochthonous strains grew well in fermented mango juice (FMJ) and remained viable at 9.81 log cfu mL^?1 during 30 days of storage at 4°C. The content of total sugar of FMJ was lower than that of MJ, while the concentration of mannitol was higher than that of MJ, and the concentration of diacetyl was 3.29 ± 0.12 mg L^?1. Among detected organic acids including citric acid, gallic acid, lactic acid, and acetic acid, only citric acid and gallic acid were found in MJ, while all detected organic acids were found in FMJ. The concentration of lactic acid of FMJ was the highest (78.62 ± 13.66 mM) among all detected organic acids. The DPPH radical scavenging capacity of FMJ was higher than that of MJ. Total phenolic compounds were better preserved in FMJ. The acidity and sweetness had a noticeable impact on the overall acceptance of the treated sample.     

Isolation and characterization of bacteriophages from fermenting sauerkraut

This paper presents the first report of bacteriophage isolated from commercial vegetable fermentations. Nine phages were isolated from two 90-ton commercial sauerkraut fermentations. These phages were active against fermentation isolates and selected Leuconostoc mesenteroides and Lactobacillus plantarum strains, including a starter culture. Phages were characterized as members of the Siphoviridae and Myoviridae families. All Leuconostoc phages reported previously, primarily of dairy origin, belonged to the Siphoviridae family.     

Microbiology of sayur asin fermentation

Summary Sayur asin is a fermented mustard cabbage product of Indonesia. The cabbage is fermented naturally in the presence of brined water taken from boiled rice. Fermentation was characterized by a sequential growth of the lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus confusus, Lactobacillus curvatus, Pediococcus pentosaceus, and Lactobacillus plantarum. Starch degrading species of Bacillus, Staphylococcus and Corynebacterium exhibited limited growth during the first day of fermentation. The yeasts, Candida sake and Candida guilliermondii contributed to the fermentation. Lactic acid, acetic acid, succinic acid, ethanol and glycerol were products of fermentation. Glucose, generated by the degradation of rice starch and maltose, was metabolized by the species that grew.     

Screening and molecular identification of potential probiotic lactic acid bacteria in effluents generated during ogi production

Screening and molecular identification of probiotic lactic acid bacteria (LAB) in effluents generated during the production of ogi, a fermented cereal (maize, millet, and sorghum) were done. LAB were isolated from effluents generated during the first and second fermentation stages in ogi production. Bacterial strains isolated were identified microscopically and phenotypically using standard methods. Probiotic potential properties of the isolated LAB were investigated in terms of their resistance to pH 1.5 and 0.3% bile salt concentration for 4 h. The potential LAB isolates ability to inhibit the growth of pathogenic organisms (Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium) was evaluated in vitro. The pH and LAB count in the effluents ranged from 3.31 to 4.49 and 3.67 to 4.72 log cfu/ml, respectively. A total of 88 LAB isolates were obtained from the effluents and only 10 LAB isolates remained viable at pH 1.5 and 0.3% bile salt. The zones of inhibition of the LAB isolates with probiotic potential ranged from 7.00 to 24.70 mm against test organsisms. Probiotic potential LAB isolates were molecularly identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus reuteri, Enterococcus faecium, Pediococcus acidilactici, Pediococcus pentosaceus, Enterococcus faecalis, and Lactobacillus brevis. Survival and proliferation of LAB isolates at low pH, 0.3% bile salt condition, and their inhibition against some test pathogens showed that these LAB isolates could be a potential probiotics for research and commercial purposes.     

Über die Bildung von flüchtigen Gärungsnebenprodukten durch Milchsäurebakterien

Zusammenfassung Die Bildung von flüchtigen Gärungsnebenprodukten durch Milchsäurebakterien wurde gaschromatographisch durch Analyse des Dampfraumes über den Kulturlösungen und Analyse von Ätherextrakten untersucht. Da von den meisten Substanzen nur sehr geringe Mengen gebildet werden, war es wegen des Vorkommens störender Substanzen in den Medien erforderlich, zur Kultur der Organismen synthetische Nährlösungen zu verwenden. In den Kulturlösungen der 3 homofermentativen Milchsäurebakterien Lactobacillus plantarum, Pediococcus cerevisiae und P. pentosaceus wurden nur Acetaldehyd, Acetoin, Diacetyl, sowie Spuren von 2- oder 3-Methyl-1-butanol, Isobutanol und 2 nicht identifizierte Substanzen gefunden. Bei den heterofermentativen Arten Lactobacillus brevis und Leuconostoc oenos wurde (neben Äthanol) zusätzlich die Bildung von sehr geringen Mengen von Propanol, i-Propanol, Essigsäureäthylester, n-Hexanol, 2,3-Butandiol, n-Octanol, n-Nonanol (oder Phenylacetaldehyd) und einiger weiterer Verbindungen nachgewiesen.

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On the formation of volatile by-products of fermentation by lactic acid bacteria

Summary The formation of volatile by-products of fermentation by several strains of lactic acid bacteria was investigated by gas liquid chromatography. Since only very small amounts of volatile compounds were formed, the synthetic media used for the growth of the bacteria had to be stripped by vacuum distillation from substances interfering with the analysis. The culture solutions were analysed by gas chromatography using both the head-space-technique and extraction with ethyl ether. The homofermentative species Lactobacillus plantarum, Pediococcus pentosaceus, and P. cerevisiae were found to form small amounts of acetaldehyde, acetoin, diacetyl and traces of 2- or 3-methyl-1-butanol, isobutanol and two compounds that were not identified. In the culture solutions of the heterofermentative species L. brevis and Leuconostoc oenos a greater number of substances could be detected. These bacteria formed, besides ethanol and the products of the homofermentative organisms, small amounts of propanol, isopropanol, ethylacetate, n-hexanol, 2,3-butandiol, n-octanol and a few unidentified compounds.

     

An ecological study of lactic acid bacteria from Almagro eggplant fermentation brines

AIM: Identification of the predominant lactic acid bacteria (LAB) involved in spontaneous fermentations of Almagro eggplants, and evaluation of the biodiversity by molecular typing. METHODS AND RESULTS: Almagro eggplant fermentations in three factories (A, B and C) enjoying Protected Designation of Origin (PDO) status were monitored by chemical and microbiological analysis of brines. LAB isolates from brines were identified by phenotypic analysis and by species-specific PCR reactions and typed by randomly amplified polymorphic DNA (RAPD)-PCR. All isolates from factories A and C belonged to the genus Lactobacillus (Lact.), whereas isolates from factory B belonged to Lactobacillus (50%), Leuconostoc (Ln.) (25%) and Lactococcus (Lc.) (25%); 1.9% of this microbiota was considered cosmopolitan. The genera Leuconostoc and Lactococcus and the species Lact. acidophilus and Lact. paracasei had never previously been reported in Almagro eggplant fermentations. CONCLUSION: Considerable differences in the composition of the lactic acid microbiota participating in the Almagro eggplant fermentations exist. Brine NaCl concentration has a notable influence both in number and in the species participating. SIGNIFICANCE AND IMPACT OF THE STUDY: The original aspect of this work consists of an ecological study of the LAB taking part in spontaneous Almagro eggplant fermentations from different factories. Participation of Leuconostoc and Lactococcus species and of Lact. acidophilus and Lact. paracasei, which had never before been described for this pickle, and the evidence that a lactic fermentation does not always take place, were the most relevant results.     

Antimicrobial susceptibility of microflora from ovine cheese

Strains identified in ovine cheese and bryndza by matrix-assisted laser desorption/ionization time-of-flight analysis belonged to ten species of non-enterococcal lactic acid bacteria and included Lactobacillus casei/Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus helveticus, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus brevis, Lactococcus lactis, Pediococcus pentosaceus and Pediococcus acidilactici. The susceptibility toward antibiotics was determined in lactobacilli, lactococci and pediococci and also in Escherichia coli for comparison. Analysis of L. fermentum and pediococci revealed the presence of non-wild-type epidemiological cut-offs in streptomycin, clindamycin or gentamicin. E. coli were resistant to ampicillin, tetracycline, enrofloxacin and florfenicol. No extended spectrum β-lactamases were detected.     

Lactic Acid Bacteria and Yeasts as Means of Decreasing Wine Acidity

Two hundred monocultures of lactic acid bacteria and 30 associations of yeasts and lactic acid bacteria have been studied. A stable association was developed which was capable of decreasing wine acidity. The association contained two species of bacteria, Leuconostoc oenosand Pediococcus pentosaceus, and the yeast Saccharomyces cerevisiae. The physiology of the microorganisms was studied, and their effects on the chemical composition of wines were determined.