Effect of Lactobacillus plantarum as a starter on the food quality and microbiota of kimchi

Lactobacillus plantarum has been reported to be responsible for acid increase at the later stage of kimchi fermentation and considered not inappropriate as a starter of kimchi. If functional L. plantarum strain can survive in large quantity in kimchi during fermentation, it may endow new functionality to kimchi. After 12 day fermentation at 4°C, L. plantarum, Leuconostoc mesenteroides, Weissella cibaria, Weissella confusa, and Lactobacillus sakei were the most prevalent ones in kimchi without a starter. In kimchi with a starter, L. plantarum was detected from the 1 day fermentation and throughout 25 day fermentation. There was no difference in pH between 2 kinds of kimchi. The acid content after the 21 day increased more in kimchi with starter when most kimchi is consumed before this time. Survival of a starter strain throughout the whole fermentation suggested the possible use of various functional lactic acid-producing bacterias (LABs) to kimchi endowing a new beneficial function to kimchi.     

Identification of the lactic acid bacteria in Kimchi according to initial and over-ripened fermentation using PCR and 16S rRNA gene sequence analysis

This paper aimed to identify the lactic acid bacteria species involved in kimchi fermentation at different fermentation periods by using culture-independent 16S rRNA gene clone libraries, and develop polymerase chain reaction for the detection of lactic acid bacteria (LAB). We investigated 6 commercially produced kimchi samples, including kimchi at an initial stage of fermentation and kimchi that was fermented to an over-ripened stage. The results of our study show that the analysis with cultureindependent 16S rRNA gene clone libraries could successfully identify 134 clones, 11 species, including Weissella, Lactobacillus, Pediococcus, and Leuconostoc from the 6 commercial kimchi samples. Weisella koreensis and Lactobacillus brevis were the predominant LAB in the initial stage of kimchi fermentation at 4°C (pH 4.96–5.27 and acidity 0.81–0.88), and Leuconostoc gelidum and Lactobacillus sakei subsp. sakei may play an important role in kimchi fermentation at the over-ripened stage (pH 3.61–3.91 and acidity 1.70–1.79).     

Source Tracking and Succession of Kimchi Lactic Acid Bacteria during Fermentation

This study aimed at evaluating raw materials as potential lactic acid bacteria (LAB) sources for kimchi fermentation and investigating LAB successions during fermentation. The bacterial abundances and communities of five different sets of raw materials were investigated using plate‐counting and pyrosequencing. LAB were found to be highly abundant in all garlic samples, suggesting that garlic may be a major LAB source for kimchi fermentation. LAB were observed in three and two out of five ginger and leek samples, respectively, indicating that they can also be potential important LAB sources. LAB were identified in only one cabbage sample with low abundance, suggesting that cabbage may not be an important LAB source. Bacterial successions during fermentation in the five kimchi samples were investigated by community analysis using pyrosequencing. LAB communities in initial kimchi were similar to the combined LAB communities of individual raw materials, suggesting that kimchi LAB were derived from their raw materials. LAB community analyses showed that species in the genera Leuconostoc, Lactobacillus, and Weissella were key players in kimchi fermentation, but their successions during fermentation varied with the species, indicating that members of the key genera may have different acid tolerance or growth competitiveness depending on their respective species.     

Analysis of volatile compounds produced by different species of lactobacilli in rye sourdough using multiple headspace extraction

Profiles of volatile organic compound (VOC) produced by nine individual lactic acid bacteria (LAB) during rye sourdough fermentation were compared by automated SPME and GC/MS‐Tof. The dough samples were inoculated with individual strains, placed inside the headspace vials and incubated during next 24 h. The production or loss of VOC‐s was followed by adsorbing volatiles onto 85‐m Car/PDMS fibre in every 4 h. Volatile profiles differed among LAB species and divided LAB into two main groups – hetero‐ and homofermentative. Hetrofermentative LAB (Lactobacillus brevis; Leuconostoc citreum; Lactobacillus vaginalis, Lactobacillus panis) showed high production of acetic acid, CO₂, ethanol, ethylacetate, producing also hexyl acetate, ethyl hexanoate and isopentyl acetate. Whereas homofermentative LAB species (Lactobacillus helveticus; Lactobacillus casei; Lactobacillus sakei; Lactobacillus curvatus) produced a considerable amount of 2,3‐butanedione. Production of l ‐leucine methyl ester was unique for Lb. sakei, Lb. casei and Lb. curvatus strains. Lb. helveticus was the only LAB that produced benzaldehyde.     

Effects of Leuconostoc mesenteroides starter cultures on microbial communities and metabolites during kimchi fermentation

Kimchi fermentation usually relies upon the growth of naturally-occurring various heterofermentative lactic acid bacteria (LAB). This sometimes makes it difficult to produce kimchi with uniform quality. The use of Leuconostoc mesenteroides as a starter has been considered to produce commercial fermented kimchi with uniform and good quality in Korea. In this study, a combination of a barcoded pyrosequencing strategy and a ¹H NMR technique was used to investigate the effects of Leu. mesenteroides strain B1 as a starter culture for kimchi fermentation. Baechu (Chinese cabbage) and Chonggak (radish) kimchi with and without Leu. mesenteroides inoculation were prepared, respectively and their characteristics that included pH, cell number, bacterial community, and metabolites were monitored periodically for 40 days. Barcoded pyrosequencing analysis showed that the numbers of bacterial operational taxonomic units (OTU) in starter kimchi decreased more quickly than that in non-starter kimchi. Members of the genera Leuconostoc, Lactobacillus, and Weissella were dominant LAB regardless of the kimchi type or starter inoculation. Among the three genera, Leuconostoc was the most abundant, followed by Lactobacillus and Weissella. The use of Leu. mesenteroides as a starter increased the Leuconostoc proportions and decreased the Lactobacillus proportions in both type of kimchi during kimchi fermentation. However, interestingly, the use of the kimchi starter more highly maintained the Weissella proportions of starter kimchi compared to that in the non-starter kimchi until fermentation was complete. Metabolite analysis using the ¹H NMR technique showed that both Baechu and Chonggak kimchi with the starter culture began to consume free sugars earlier and produced a little greater amounts of lactic and acetic acids and mannitol. Metabolite analysis demonstrated that kimchi fermentation using Leu. mesenteroides as a starter was completed earlier with more production of kimchi metabolites compared to that not using a starter, which coincided with the decreases in pH and the increases in bacterial cell number. The PCA strategy using all kimchi components including carbohydrates, amino acids, organic acids, and others also showed that starter kimchi fermented faster with more organic acid and mannitol production. In conclusion, the combination of the barcoded pyrosequencing strategy and the ¹H NMR technique was used to effectively monitor microbial succession and metabolite production and allowed for a greater understanding of the relationships between the microbial community and metabolite production in kimchi fermentation.     

Combination of culture-dependent and culture-independent molecular methods for the determination of lactic microbiota in sucuk

In this study, the culture-dependent and culture-independent molecular methods were used for the identification of lactic acid bacteria (LAB) in sucuk a Turkish fermented dry sausage. On the one hand, the PCR-DGGE method targetting the V1 and V3 regions of 16S DNA was applied to DNA that was directly extracted from sucuk samples. On the other hand, rep-PCR fingerprinting was performed for the primary differentiation and grouping of the isolates, and the results were confirmed by sequencing of the 16S rDNA and 16S-23S rDNA intergenic spacer region. As a result of the PCR-DGGE analysis of all the samples, total 8 different lactic acid bacteria were identified, and Lactobacillus sakei, Lactobacillus curvatus and Weissella viridescens were the dominant microbiota among these bacteria. The culture-dependent approach indicated that the majority of the strains belonged to the Lactobacillus genera including Lb. sakei, Lactobacillus plantarum, Lb. curvatus, Lactobacillus brevis, Lactobacillus farciminis and Lactobacillus alimentarius. However, Leuconostoc and Weisella were also detected as minor genera. Again, Lactococcus piscium, Weissella halotolerans, Staphylococcus succinus and the comigrated Staphylococcus piscifermentans/Staphylococcus condimenti/Staphylococcus carnosus group were detected only with the culture-independent method while Lb. plantarum, Leuconostoc mesenteroides and Leuconostoc citreum were identified only by using the culture-dependent method. In the results, it was concluded that the combination of culture-dependent and culture-independent methods was necessary for reliable and detailed investigation of LAB communities in fermented food products.     

Isolation and characterisation of lactic acid bacteria from jiang-gua (fermented cucumbers), a traditional fermented food in Taiwan

BACKGROUND: Jiang‐gua (fermented cucumbers) is a popular traditional fermented food in Taiwan. The microflora of lactic acid bacteria (LAB) in jiang‐gua have not been investigated in detail. In this study, LAB from jiang‐gua were isolated, characterised and identified. RESULTS: A total of 103 LAB were isolated; 70 cultures were isolated from jiang‐gua samples and 33 cultures were isolated from its raw substrate, cucumber. These isolates were mainly characterised phenotypically and then divided into seven groups (A‐G) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. The isolates were identified as Enterococcus casseliflavus, Leuconostoc lactis, Leuconostoc mesenteroides, Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus paraplantarum, Lactococcus lactis subsp. lactis, Weissella cibaria and Weissella hellenica. The antibacterial activities of the isolates were determined and 11 Lc. lactis subsp. lactis strains showed inhibitory activity against the indicator strain Lactobacillus sakei JCM 1157^T. CONCLUSION: Heterofermentative W. cibaria and Leu. lactis were the major LAB found in jiang‐gua samples without soy sauce. In soy sauce‐added samples, homofermentative L. pentosus and L. plantarum were the most abundant LAB. In addition, the results also suggested that HhaI and RsaI restriction enzymes could be applied to distinguish W. hellenica and Weissella paramesenteroides. Copyright © 2012 Society of Chemical Industry     

Diversity of lactic acid bacteria in suan-tsai and fu-tsai, traditional fermented mustard products of Taiwan

Fu-tsai and suan-tsai are spontaneously fermented mustard products traditionally prepared by the Hakka tribe of Taiwan. We chose 5 different processing stages of these products for analysis of the microbial community of lactic acid bacteria (LAB) by 16S rRNA gene sequencing. From 500 LAB isolates we identified 119 representative strains belonging to 5 genera and 18 species, including Enterococcus (1 species), Lactobacillus (11 species), Leuconostoc (3 species), Pediococcus (1 species), and Weissella (2 species). The LAB composition of mustard fermented for 3 days, known as the Mu sample, was the most diverse, with 11 different LAB species being isolated. We used sequence analysis of the 16S rRNA gene to identify the LAB strains and analysis of the dnaA, pheS, and rpoA genes to identify 13 LAB strains for which identification by 16S rRNA gene sequences was not possible. These 13 strains were found to belong to 5 validated known species: Lactobacillus farciminis, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Weissella cibaria, and Weissella paramesenteroides, and 5 possibly novel Lactobacillus species. These results revealed that there is a high level of diversity in LAB at the different stages of fermentation in the production of suan-tsai and fu-tsai.     

Biodiversity of lactic acid bacteria and yeasts in spontaneously-fermented buckwheat and teff sourdoughs

In this study, four different laboratory scale gluten-free (GF) sourdoughs were developed from buckwheat or teff flours. The fermentations were initiated by the spontaneous biota of the flours and developed under two technological conditions (A and B). Sourdoughs were propagated by continuous back-slopping until the stability was reached. The composition of the stable biota occurring in each sourdough was assessed using both culture-dependent and -independent techniques. Overall, a broad spectrum of lactic acid bacteria (LAB) and yeasts species, belonging mainly to the genera Lactobacillus, Pediococcus, Leuconostoc, Kazachstania and Candida, were identified in the stable sourdoughs. Buckwheat and teff sourdoughs were dominated mainly by obligate or facultative heterofermentative LAB, which are commonly associated with traditional wheat or rye sourdoughs. However, the spontaneous fermentation of the GF flours resulted also in the selection of species which are not consider endemic to traditional sourdoughs, i.e. Pediococcus pentosaceus, Leuconostoc holzapfelii, Lactobacillus gallinarum, Lactobacillus vaginalis, Lactobacillus sakei, Lactobacillus graminis and Weissella cibaria. In general, the composition of the stable biota was strongly affected by the fermentation conditions, whilst Lactobacillus plantarum dominated in all buckwheat sourdoughs. Lactobacillus pontis is described for the first time as dominant species in teff sourdough. Among yeasts, Saccharomyces cerevisiae and Candida glabrata dominated teff sourdoughs, whereas the solely Kazachstania barnetti was isolated in buckwheat sourdough developed under condition A. This study allowed the identification and isolation of LAB and yeasts species which are highly competitive during fermentation of buckwheat or teff flours. Representatives of these species can be selected as starters for the production of sourdough destined to GF bread production.     

Molecular and technological characterization of lactic acid bacteria from traditional fermented sausages of Basilicata region (Southern Italy)

Lactic acid bacteria (LAB) from traditional fermented sausages of the Basilicata region were investigated by ARDRA-PCR and RAPD-PCR for taxonomic identification at species and strain level and characterized on the basis of the growth and acidification at different temperatures, incubation times, levels of NaCl and KNO₂, hydrolysis of sarcoplasmatic and myofibrillar proteins and antimicrobial, peptide/amino acid release and nitrate reductase activities.Lactobacillus sakei was the predominant species (67%) followed by Pediococcus pentosaceus (16%), Leuconostoc carnosum (8%), Lactobacillus plantarum (4%), Lactobacillus brevis (2%) and Leuconostoc pseudomesenteroides (2%). The technological characterization revealed that most of the isolates had good acidifying and proteolytic properties. Moreover, Lb. sakei strains showed antimicrobial ability, while Leuconostoc strains the highest reduction of nitrates.This work was a preliminary study in the formulation of autochthonous starter cultures in order to standardize the production process of sausages, to preserve their typical organoleptic and sensory characteristics and to improve the quality of final product.     

Characterization of Proteolytic Effect of Lactic Acid Bacteria Starter Cultures on Thai Fermented Sausages

The objective of this study was to investigate the effect of starter culture addition on proteolysis of Thai fermented sausages. Sausages inoculated with six different external starter cultures—Pediococcus pentosaceous, Pediococcus acidilactici, Weissella cibaria, Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus sakei—were compared with naturally fermented sausages. The results of microbiological analysis indicated that the dominance of lactic acid bacteria (LAB) could inhibit the growth of pathogens and spoilage. Proteolysis was observed during fermentation by the reduction of myofibrillar and sarcoplasmic proteins and the increase in nonprotein nitrogen (NPN) and total free amino acids. The highest increase in concentration of NPN and free amino acids was obtained from sausages inoculated with LAB. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed a similar pattern of proteolysis of sarcoplasmic proteins in all sausages, while that of the inoculated sausages with L. plantarum, L. pentsus, and L. sakei exhibited increased degradation of myofibrillar protein bands at 200 and 45 kDa.     

Effects of Different Salt Treatments on the Fermentation Metabolites and Bacterial Profiles of Kimchi

The effects of purified salt (PS) and mineral‐rich sea salt (MRS), both with different mineral profiles, on kimchi fermentation were studied using a culture‐dependent 16S rRNA sequencing technique and mass‐based metabolomic analysis. The different mineral profiles in the fermentation medium caused changes in the bacterial profiles of the 2 kimchi products. An increase of Leuconostoc species in MRS‐kimchi decreased the Lactobacillus/Leuconostoc ratio, which led to changes in metabolites (including sugars, amino acids, organic acids, lipids, sulfur compounds, and terpenoids) associated with kimchi quality. Although further studies on the relationship between these salt types and kimchi fermentation are needed, these results suggested that the MRS treatment had positively affected the changes of the kimchi mineral contents, bacterial growth, and metabolite profiles, which are linked to kimchi quality.     

Natural populations of lactic acid bacteria isolated from vegetable residues and silage fermentation

Natural populations of lactic acid bacteria (LAB) and silage fermentation of vegetable residues were studied. Fifty-two strains of LAB isolated from cabbage, Chinese cabbage, and lettuce residues were identified and characterized. The LAB strains were gram-positive and catalase-negative bacteria, which were divided into 6 groups (A to F) according to morphological and biochemical characteristics. The strains in group A were rods that did not produce gas from glucose and formed the d and l isomers of lactate. Groups B and C were homofermentative cocci that formed l-lactic acid. Groups D, E, and F were heterofermentative cocci that formed d-lactic acid. Based on 16S rDNA gene sequence analysis, group A to F strains were identified as Lactobacillus plantarum, Lactococcus piscium, Lactococcus lactis, Leuconostoc citreum, Weissella soli and Leuconostoc gelidum, respectively. The prevalent LAB, predominantly homofermentative lactobacilli, consisted of Lactobacillus plantarum (34.6%), Weissella soli (19.2%), Leuconostoc gelidum (15.4%), Leuconostoc citreum (13.5%), Lactococcus lactis (9.6%), and Lactococcus piscium (7.7%). Lactobacillus plantarum was the dominant member of the LAB population in 3 types of vegetable residues. These vegetable residues contained a high level of crude protein (20.2 to 28.4% of dry matter). These silages prepared by using a small-scale fermentation system were well preserved, with low pH and a relatively high content of lactate. This study suggests that the vegetable residues contain abundant LAB species and nutrients, and that they could be well preserved by making silage, which is a potentially good vegetable protein source for livestock diets.     

Isolation and characterisation of lactic acid bacteria from yan-jiang (fermented ginger), a traditional fermented food in Taiwan

BACKGROUND: Yan‐jiang (fermented ginger) is a popular traditional fermented food in Taiwan. The lactic acid bacteria (LAB) microflora in yan‐jiang has not been studied in detail. In this study, LAB from yan‐jiang were isolated, characterised and identified. RESULTS: A total of 176 LAB were isolated; 160 cultures were isolated from yan‐jiang samples and 16 cultures were isolated from raw ginger. These isolates were characterised phenotypically and then divided into nine groups (A to I) by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA. Lactobacillus sakei and Lactococcus lactis subsp. lactis were the major LAB found in the initial 2 days of fermentation without pickled plums; these species were mostly replaced by Weissella cibaria and L. plantarum after 3 days of fermentation. In the fermentation bucket with added pickled plums, W. cibaria was the most abundant LAB found during fermentation. The antibacterial activities of the isolates were determined. Twenty‐four Lc. lactis subsp. lactis and 19 W. cibaria strains showed inhibitory activity against the indicator strain L. sakei JCM 1157^T. CONCLUSION: Results demonstrate that various LAB species were more numerous when fermentation was carried out without pickled plums. LAB also had effects on the aroma and flavour of yan‐jiang. Copyright © 2011 Society of Chemical Industry     

Distribution of lactic acid bacteria in garlic (Allium sativum) and green onion (Allium fistulosum) using SDS-PAGE whole cell protein pattern comparison and 16S rRNA gene sequence analysis

Distributions of lactic acid bacteria (LAB) in garlic and green onion samples as kimchi sub-ingredients were analyzed by comparing the SDS-PAGE whole cell protein patterns and 16S rRNA gene sequence analysis. In total, 245 LAB were isolated from 10 garlic samples and differentiated into 7 groups by comparing SDS-PAGE whole cell protein patterns. The groups were identified as Leuconostoc, Weissella, and Lactobacillus through the 16S rRNA gene sequence analysis. A total of 115 LAB were isolated from 7 green onion samples, differentiated into 6 groups, and identified as Weissella, Leuconostoc, and Lactococcus. Leuconostoc was the most dominated LAB in garlic and Weissella was the most dominated LAB in green onion. The LAB identified in this study was found as dominant microorganisms in kimchi. This result suggests the possible contribution of LAB in garlic and green onion to the bacterial microflora of kimchi, especially during early stage of fermentation.     

Species diversity,community dynamics,and metabolite kinetics of spontaneous leek fermentations

Leek (Allium ampeloprasum var. porrum) is one of Belgium's most important vegetables. All or part of the green leek parts are often left on the fields because of their limited cooking applications compared to the white leek parts. Therefore, the possibility to perform leek fermentations in view of product valorization and diversification was investigated. This study deals with the community dynamics, species diversity, and metabolite kinetics of spontaneous leek fermentations, thereby studying the influence of added NaCl concentration, harvesting season, and duration of the fermentation. The combination of a culture-dependent and culture-independent approach revealed the prevalence of lactic acid bacteria (LAB) from the third day of fermentation onwards, which was not influenced by the fermentation conditions applied. Enterobacteriaceae, Pseudomonadaceae, and yeasts disappeared after one week of fermentation. Leuconostoc mesenteroides, Lactobacillus sakei, and Lactobacillus plantarum, Lactobacillus brevis, and Lactobacillus parabrevis were the most frequently isolated LAB species. Both added NaCl concentrations were suitable to perform successful fermentations within three weeks. By that time, glucose and fructose, the main leek carbohydrates, were metabolized into mainly lactic acid, acetic acid, ethanol, and mannitol. A sensory analysis revealed that the fermented white leek parts were generally more appreciated than the fermented green leek parts.     

Halotolerance and Survival Kinetics of Lactic Acid Bacteria Isolated from Jalapeño Pepper (Capsicum annuum L.) Fermentation

The microbiota associated with spontaneous fermentation of vegetables in a saline substrate may represent an important group of bacteria in the food industry. In this work, the lactic acid bacteria (LAB) Weissella cibaria, Lactobacillus plantarum, Lactobacillus paraplantarum, and Leuconostoc citreum were identified by partial 16S rRNA gene sequence analysis. In addition, entophytic bacteria such as Pantoea eucalypti, Pantoea anthophila, Enterobacter cowanii, and Enterobacter asburiae were detected, but they were irrelevant for the fermentation process and were inhibited after 12 h of fermentation when the pH decreased from 6.5 to 4.9. Moreover, 2 species of yeast were isolated and identified as Hanseniaspora pseudoguilliermondii and Kodamaea ohmeri by their partial 26S rRNA gene sequence. The growth of LAB was evaluated at different sodium chloride contents. L. citreum was the most halotolerant species followed by L. plantarum and W. cibaria with a concentration index to obtain a 50% population reduction (IC₅₀) of 7.2%, 6.6%, and 5.2%, respectively. Furthermore, the growth of LAB and Escherichia coli O157:H7 was evaluated in the presence of the main phenylpropanoids from chilli peppers such as p‐coumaric and ferulic acid. It was determined that LAB can grow in both acids at 4 mM, unlike E. coli O157:H7, whose growth is inhibited in the presence of these acids.     

A novel NADH fluorescence-based method for identifying and monitoring lactic acid bacteria growths in kimchi

NADH-based fluorescence method was developed to enumerate and differentiate lactic acid bacteria (LAB). The growths of LAB were determined at −1.5–30 ℃ in MRS medium and kimchi juice. LAB growths were measured by viable cell counting and measuring culture turbidity (A₆₀₀) and NADH fluorescence at 460 nm (F₄₆₀). Each LAB strain had a unique F₄₆₀ value at different growth temperatures. Based on the F₄₆₀ values of LAB strains cultivated at different temperatures, LAB were identified and counted at the species and genus levels in MRS medium and kimchi juice. The fluorescence method was also used to measure changes in LAB dynamics during kimchi fermentation. Obvious increases in F₄₆₀ values were observed for kimchi samples with LAB counts of > 8 log CFU mL⁻¹, except for Weissella koreensis. Our results indicate that the devised NADH fluorescence method can be used to determine the progress of kimchi fermentation and LAB growths during kimchi storage.     

Monitoring the lactic acid bacterial diversity during shochu fermentation by PCR-denaturing gradient gel electrophoresis

The presence of lactic acid bacteria (LAB) during shochu fermentation was monitored by PCR-denaturing gradient gel electrophoresis (DGGE) and by bacteriological culturing. No LAB were detected from fermented mashes by PCR-DGGE using a universal bacterial PCR primer set. However, PCR-DGGE using a new primer specific for the 16S rDNA of Lactococcus, Streptococcus, Tetragenococcus, Enterococcus, and Vagococcus and two primers specific for the 16S rDNA of Lactobacillus, Pediococcus, Leuconostoc, and Weissella revealed that Enterococcus faecium, Lactobacillus casei, Lactobacillus fermentum, Lactobacillus nagelii, Lactobacillus plantarum, Lactococcus lactis, Leuconostoc citreum, Leuconostoc mesenteroides, and Weissella cibaria inhabited in shochu mashes. It was also found that the LAB community composition during shochu fermentation changed after the main ingredient and water were added during the fermentation process. Therefore, we confirmed that PCR-DGGE using all three primers specific for groups of LAB together was well suited to the study of the LAB diversity in shochu mashes. The results of DGGE profiles were similar to the results of bacteriological culturing. In conclusion, LAB are present during shochu fermentation but not dominant.     

Lactic acid bacteria population dynamics during minced beef storage under aerobic or modified atmosphere packaging conditions

A total of 266 lactic acid bacteria (LAB) have been isolated from minced beef stored at 0, 5, 10 and 15 °C aerobically and under modified atmosphere packaging consisting of 40% CO₂–30% O₂–30% N₂ in the presence MAP (+) and absence MAP (−) of oregano essential oil. Sequencing of their 16S rRNA gene along with presence of the katA gene demonstrated dominance of the LAB microbiota by Leuconostoc spp. during aerobic storage at 5, 10 and 15 °C, as well as during MAP (−) and MAP (+) storage at 10 and 15 °C; Lactobacillus sakei prevailed during aerobic storage at 0 °C, as well as at MAP (−) and MAP (+) storage at 0 and 5 °C. The sporadic presence of other species such as Leuconostoc mesenteroides, Weisella viridescens, Lactobacillus casei and Lactobacillus curvatus has also been determined. Pulsed-Field Gel Electrophoresis of high molecular weight genomic DNA revealed the dynamics of the isolated LAB strains. Prevalence of Leuconostoc spp. was attributed to one strain only. On the other hand, packaging conditions affected Lb. sakei strain spoilage dynamics.