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This work aimed to evaluate the impact of inoculation single and co-cultivation of LAB and yeasts during the wet process of Coffea canephora using the self-induced anaerobic fermentation method. Saccharomyces cerevisiae, Totulaspora delbrueckii delbrueckii, Leuconostoc mesenteroides, and Lactiplantibacillus plantarum were monitored during fermentation. L. mesenteroides was detected in high concentrations in the coffee fruits (8.54 log10 cells/mL) and remained until the end of fermentation. Lactic and acetic acids were the main acids produced during fermentation. After 36 h of fermentation, 75.39% of malic acid was consumed in the L. mesenteroides + S. cerevisiae (MC) fermentations. In roasted coffee, the caffeine concentration reached 3.29 higher than the green beans in MC fermentation. Specific volatile compounds were detected in inoculated fermentation and may contribute to the beverage quality. Coffee inoculated with Leuconostoc mesenteroides was classified as fine (80.0-89.0), while the other fermentations were classified as premium (70.0-79.0). L. mesenteroides inoculation showed the best sensory score, and the beverage was characterized by caramel, fruity, and spices notes. L. mesenteroides inoculated alone or in co-culture with S. cerevisiae are promising starter cultures to improve Conilon coffee quality and obtain beverages with differentiated sensory profiles.

To investigate the fermentative characteristics of Bacillus and lactic acid bacteria, the key microbes known to be involved in doenjang-meju (a Korean traditional fermented soybean brick) fermentation, we prepared and analyzed two sets of doenjang-meju inoculated with either Aspergillus oryzae and Bacillus velezensis (BDM) or A. oryzae and Leuconostoc mesenteroides (LDM). A large decrease in pH was observed during the early fermentation period in LDM, whereas the pH remained relatively constant in BDM. Although observed in higher levels in BDM during the early fermentation period, free sugar and amino acid contents and Aspergillus abundance were higher in LDM thereafter, which aligned with α-amylase and protease activity profiles in LDM and BDM, suggesting their association with Aspergillus. Higher levels of isoflavone aglycones and glycerol along with greater β-glucosidase and lipase activities in LDM and BDM, respectively, were suggestive of the characteristics of Leuconostoc and Bacillus, respectively. More diverse and higher amounts of volatile compounds were observed in BDM than in LDM. The α-amylase, lipase, protease, β-glucosidase, and antimicrobial activities of A. oryzae, B. velezensis, and L. mesenteroides were examined through genomic analyses and in vitro assays, which well supported the results of their fermentative characteristics in LDM and BDM.

Repetitive-PCR (rep-PCR) is a well-established genetic method for bacterial strain fingerprinting that is used mostly with REP, ERIC, (GTG)5, BOXA1R and occasionally BOXA2R repetitive primers. In this study, it was demonstrated that BOXA2R-PCR could effectively discriminate between Lactococcus lactis, Leuconostoc mesenteroides and Streptococcus thermophilus; differentiate Lactococcus lactis strains and subspeciate them into lactis and cremoris in a single reaction; generate unique strain fingerprints of various lactic acid bacteria (LAB species) commonly isolated from fermented dairy products, including occasional spoilage bacteria and yeasts. Furthermore, using direct colony PCR a reproducible and rapid method was developed for the differentiation and identification of lactic acid cocci. The simplicity and speed of this microbial identification method has potential practical value for dairy microbiologists, which was demonstrated through a microbiota investigation of select Australian retail dairy products.

Lactococcus lactis subsp. lactis biovar diacetylactis and Leuconostoc mesenteroides are considered to be the main aroma producers in Dutch-type cheeses. Both species of lactic acid bacteria were grown in retentostat mono- and co-cultures to investigate their interaction at near-zero growth rates and to determine if co-cultivation enhances the aroma complexity compared to single species performance. During retentostat mono-cultures, the growth rates of both species decreased to less than 0.001 h −1 and a large fraction of the cells became viable but not culturable. Compared to Lc. mesenteroides, L. lactis reached a 3.4-fold higher biomass concentration caused by i) a higher ATP yield on substrate, ii) a higher biomass yield on ATP and iii) a lower maintenance requirement (m ATP ). Dynamic models estimated that the m ATP of both species decreased approximately 7-fold at near-zero growth rates compared to high growth rates. Extension of these models by assuming equal substrate distribution resulted in excellent prediction of the biomass accumulation in retentostat co-cultures with L. lactis dominating (100:1) as observed in ripened cheese. Despite its low abundance (∼1%), Lc. mesenteroides contributed to aroma production in co-cultures as indicated by the presence of all 5 specific Lc. mesenteroides compounds. This study provides insights in the production of cheese aroma compounds outside the cheese matrix by co-cultures of L. lactis and Lc. mesenteroides, which could be used as food supplements in dairy or non-dairy products.

Kimchi is one of the primary sources of high sodium content in the Korean diet. Low-sodium kimchi is commercially manufactured to minimize the health effects of high salt. We investigated the influence of lactic acid bacteria (LAB) as starter culture in combination with 1% or 2.5% salt on the survival of pathogenic Escherichia coli and physicochemical properties of kimchi during fermentation at 10 °C and 25 °C. Among ten strains of LAB isolated from kimchi, Leuconostoc mesenteroides (KCTC 13374) and Lactobacillus plantarum (KCTC 33133) exhibited antimicrobial activities against pathogenic E. coli (EPEC, ETEC, and E. coli O157:H7) and strong tolerance to low pH (2 and 3) and 0.3% bile salts. Thus, L. mesenteroides and L. plantarum were used as starter cultures for kimchi that contained 1% and 2.5% salt. All pathogenic E. coli strains survived in kimchi regardless of starter cultures or salt concentration for over 15 days at 10 °C, but they died off within 4 days at 25 °C. Survival of pathogenic E. coli was better in naturally fermented kimchi (titratable acidity:0.65%) than kimchi fermented with starter cultures (titratable acidity:1.0%). At 10 °C, the average delta value of E. coli O157:H7 (16.15 d) was smaller than those of EPEC (20.76 d) and ETEC (20.20 d) in naturally fermented kimchi. Overall, survival ability of E. coli O157:H7 was lower than EPEC and ETEC, although differences were not significant. Reduced salt concentration from 2.5% to 1% in kimchi did not affect the growth of LAB and the fermentation period. Pathogenic E. coli died at a faster rate in kimchi fermented with starter cultures and 1% salt than in naturally fermented kimchi with 2.5% salt.

International audience; The microbiota of fresh French pork sausages were characterised in five batches of comminuted pork meat that were equally divided into two formulations either containing the acid-based preservatives lactate and acetate, or no preservatives. Conventional microbiological analysis and high-throughput 16S rDNA amplicon sequencing methods were performed on meat batches packed under modified atmosphere (70% oxygen and 30% carbon dioxide) during chilled storage. In addition, meat pH and colour, and gas composition of the packages were monitored until the end of the shelf-life. During storage, the population of mesophilic and lactic acid bacteria increased from 4 log CFU/g to 8 log CFU/g after 15 days of chilled storage, both with and without preservatives. Despite similar changes of the physical and chemical parameters, such as pH and package gas composition, spoilage was delayed in the meat containing the preservatives, suggesting that lactate and acetate are effective against spoilage. Metagenetic analysis showed that at the end of the shelf-life, the species distribution differed between both the formulations and the batches. Lactic acid bacteria were shown to dominate both with and without preservatives; however, samples containing no preservatives were characterised by the presence of an increased population of Brochothrix spp. and Pseudomonas spp. whereas, Leuconostoc mesenteroides/pseudomesenteroides and Lactobacillus curvatus/graminis were more abundant in the meat with preservatives.

The effect of iodine present in 1.0% table salt in combination with the use of starter cultures in sauerkraut fermentations were investigated in order to determine whether iodine interferes with lactic acid bacteria responsible for the fermentation. The effect of iodine was tested in fermentations performed using selected starter cultures or without starters (spontaneous fermentation). Lactobacillus plantarum and Leuconostoc mesenteroides used as starters at levels of ca. 1 × 107 cfu ml−1 led to a quick establishment of lactic acid bacteria (LAB) as predominant microorganisms, reaching 1 × 109 cfu ml−1 after 24 h decreasing the pH to below 4.0. In contrast, LAB counts in control fermentations without starters increased slower from 1 × 105 cfu ml−1 to 1 × 109 cfu ml−1 and a pH reduction below 4.0 was achieved only after 3 days fermentation. A metagenomic investigation showed a more diverse bacterial community in fermentations without starters, consisting of enterobacteria and pseudomonads in the first days of fermentation, and of LAB such as lactococci in the later stages. In fermentations with starters, lactobacilli predominated. Leuconostocs also occurred, but at much lower sequence abundance than lactobacilli, and thus were not able to predominate. Determination of iodine in the fermentation with starter bacteria and with iodized salt showed that the fermentation did not affect iodine concentration. The use of iodized salt did not statistically significantly influence microbial populations in the fermentation. Thus, there is no basis for the popular held belief that the use of iodized salt inhibits the growth of the bacteria important for the sauerkraut fermentation. A statistically near significant effect (p = 0.06), however, was noted for the effect of iodine on yeasts and mould populations in the fermentations performed without starter cultures. As sauerkraut is usually produced without starters, this should be further investigated.

This study investigated the influence of the addition of soy products on the microbiology, nutritional and physico-chemical characteristics of garri, a fermented cassava product. Malted soy flour (MSF) and soy protein (SP) were separately added (12% w/w) to cassava mash prior to controlled fermentation, while non-supplemented cassava mash served as a control. Identification of lactic acid bacteria (LAB) and aerobic mesophilic bacteria was accomplished by repetitive sequence based (rep)-PCR analysis and 16S rRNA gene sequencing. Physicochemical, nutritional and sensory characterisation of control and soy-fortified garri was performed using conventional methods. rep-PCR allowed differentiation of 142 isolates into 41 groups corresponding to 6 species of LAB and 25 species of aerobic mesophiles. LAB isolates belonged to the genera Lactobacillus, Weissella, Leuconostoc and Lactococcus with Leuconostoc mesenteroides being the dominant species in control and MSF-cassava while Weissella cibaria dominated SP-cassava fermentation. Aerobic mesophiles included Gram positive and negative bacteria including species of the genera Bacillus, Clostridium, Staphylococcus, Serratia, Acinetobacter and Raoultella. Diversity of aerobic mesophiles varied between control, MSF- and SP- cassava mash. Protein content of soy-fortified garri increased from 0.73% to 10.17% and 10.05% in MSF and SP garri respectively with a significant decrease in total cyanide from 26 to 11 ppm. Results from physicochemical and organoleptic evaluation indicate that supplementation of cassava with soy products prior to fermentation can produce acceptable garri. Soy products can be considered a viable option for protein fortification of garri, a low protein food with the aim of combating malnutrition.

Rapid colorimetric methods using various indicator reagents have been developed to monitor bacterial viability. Here, we examined the applicability of a method based on the reduction of resazurin or water-soluble tetrazolium salt-8 (WST-8) to screen lactic acid bacteria (LAB) for growth, tolerance against bile acid and low pH. The resazurin reduction test proved unsuitable for screening LAB such as Lactobacillus plantarum and Leuconostoc mesenteroides since it reacted with acid present in the cultures. LAB growth could be indirectly quantified by measuring WST-8 reduction. This method proved more sensitive and quickly results than counting bacterial colony forming units and turbidity at 600 nm in the presence of bile and acid. Our results suggested that the WST-8-based method could be useful for the characterization of growth and tolerance of the lactic acid producing bacteria.

Strains of Leuconostoc mesenteroides were identified from raw prickly pear (Opuntia ficus-indica L.). Five autochthonous strains were selected based on the kinetics of growth and acidification on prickly pear fruit juice, and the capacity to synthesize exo-polysaccharides. All selected Leuc. mesenteroides strains showed an in vitro mucilage-degrading capability. A protocol for processing and storage of fermented prickly pear fruit puree (FP) was set up. Unstarted FP and chemically acidified FP were used as the controls. Starters grew and remained viable at elevated cell numbers during 21 days of storage at 4 °C. Contaminating Enterobacteriaceae and yeasts were found only in the controls. Viscosity and serum separation distinguished started FP compared to the controls. Colour parameters, browning index, sensory attributes, antimicrobial activity, vitamin C and betalains levels were positively affected by lactic acid fermentation. Increase of free radical scavenging activity in ethyl acetate soluble extract suggested an effect of selected strains on phenolic profiles. Started FP markedly inhibited the inflammatory status of Caco-2/TC7 cells, and also contributed to maintaining the integrity of tight junctions. Started FP scavenged the reactive oxygen species generated by H2O2 on Caco-2 cells. All selected strain variously affected the immunomodulatory activity towards anti- and pro-inflammatory cytokines.

Cereal-based functional beverages represent social, economic, and environmental sustainable opportunities to cope with emerging trends in food consumption and global nutrition. Here we report, for the first time, the polyphasic characterization of three cereal-based kefir-like riboflavin-enriched beverages, obtained from oat, maize and barley flours, and their comparison with classical milk-based kefir. The four matrices were successfully fermented with commercial starters: i) milk-kefir and ii) water-kefir, proving the potential of cereal ingredients in the formulation of dairy-like fermented beverages with milk-kefir starter behavior better in these matrices. In the light of their potentiality, seven riboflavin-producing Andean Lactic Acid Bacteria (LAB) were tested for tolerance to food stresses commonly encountered during food fermentation. Moreover, the LAB strains investigated were screened for spontaneous riboflavin overproducing derivatives. Lactobacillus plantarum M5MA1-B2 with outstanding response to stress, was selected to improve riboflavin content in an in situ fortification approach. The combination of L. plantarum M5MA1-B2 riboflavin overproducing strain with milk kefir starter in oat, lead to cover, for one serving of 100 g, 11.4% of Recommended Dietary Allowance (RDA). Besides, addition of L. plantarum M5MA1-B2 improved performance of water kefir in oat and maize matrices. Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) analysis provided the on-line Volatile Organic Compounds profiles supporting the best combination of starter, LAB and cereal matrix for novel functional foods development.

This study aimed to gain deeper insights into the microbiota composition and population dynamics, monitor the dominant bacterial populations and identify the specific spoilage microorganisms (SSOs) of vacuum-packed bacon during refrigerated storage using both culture-independent and dependent methods. High-throughout sequencing (HTS) showed that the microbial composition changed greatly with the prolongation of storage time. The diversity of microbiota was abundant at the initial stage then experienced a continuous decrease. Lactic acid bacteria (LAB) mainly Leuconostoc and Lactobacillus dominated the microbial population after seven days of storage. A total of 26 isolates were identified from different growth media using traditional cultivation isolation and identification method. Leuconostoc mesenteroides and Leuconostoc carnosum were the most prevalent species since day 15, while Lactobacillus sakei and Lactobacillus curvatus were only found on day 45, suggesting that they could be responsible for the spoilage of bacon. Serratia, Rahnella, Fusobacterium and Lactococcus underwent a dramatic increase at some point in individual batchs which may be considered as potential contributors to the spoilage.

Enset (Ensete ventricosum) provides staple food for 15 million people in Ethiopia after fermentation into kocho. The fermentation process has hardly been investigated and is prone to optimization. The aim of this study was to investigate the physicochemical and microbial dynamics of fermentation practices in the Gamo highlands. These practices show local variation, but two steps were omnipresent: scraping of the pseudostem and fermenting it in a pit or a bamboo basket. Enset plants were fragmented and fermented for two months in order to investigate the physicochemical (temperature, moisture content, pH and titratable acidity) and microbial dynamics (total viable aerobic counts, counts of Enterobacteriaceae, lactic acid bacteria, yeasts and moulds and Clostridium spores counts, and Illumina Miseq sequencing). Samples were taken on days 1, 7, 15, 17, 31 and 60. The pH decreased, whereas the titratable acidity increased during fermentation. Of all counts those of lactic acid bacteria and Clostridium spores increased during fermentation. Leuconostoc mesenteroides initiated the fermentation. Later on, Prevotella paludivivens, Lactobacillus sp. and Bifidobacterium minimum dominated. These three species are potential candidates for the development of a starter culture. ispartof: FOOD MICROBIOLOGY vol:73 pages:342-350 ispartof: location:England status: published

The aim of this study was to investigate the composition of lactic acid bacteria (LAB) in autochthonous young cheeses, sweet creams and sweet kajmaks produced in the Vlašić mountain region of central Bosnia and Herzegovina near the town of Travnik over a four season period. These three products were made from cow's milk by a traditional method without the addition of a starter culture. Preliminary characterization with phenotype-based assays and identification using rep-PCR with a (GTG)5 primer and 16S rDNA sequence analysis were undertaken for 460 LAB isolates obtained from all the examined samples. Fifteen species were identified as follows: Lactococcus lactis, Lactococcus raffinolactis, Lactococcus garviae, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus helveticus, Enterococcus faecium, Enterococcus durans, Enterococcus faecalis, Enterococcus italicus, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Leuconostoc lactis, Streptococcus thermophilus and Streptococcus mitis. A wide genotypic and phenotypic heterogeneity of the species was observed, particularly within the Lc. lactis strains. In all of the tested dairy products across four seasons, a significantly positive correlation (r = 0.690) between the presence of lactococci and enterococci and a negative correlation (r = 0.722) between the presence of lactococci and leuconostocs were recorded. Forty-five percent of the lactobacilli and 54.4% of the lactococci exhibited proteolytic activity, whereas 18.7% of the total LAB isolates exhibited antimicrobial activity.

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.

The present study aims to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from naturally fermented olives and select candidates to be used as probiotic starters for the improvement of the traditional fermentation process and the production of newly added value functional foods. Seventy one (71) lactic acid bacterial strains (17 Leuconostoc mesenteroides, 1 Ln. pseudomesenteroides, 13 Lactobacillus plantarum, 37 Lb. pentosus, 1 Lb. paraplantarum, and 2 Lb. paracasei subsp. paracasei) isolated from table olives were screened for their probiotic potential. Lb. rhamnosus GG and Lb. casei Shirota were used as reference strains. The in vitro tests included survival in simulated gastrointestinal tract conditions, antimicrobial activity (against Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli O157:H7), Caco-2 surface adhesion, resistance to 9 antibiotics and haemolytic activity. Three (3) Lb. pentosus, 4 Lb. plantarum and 2 Lb. paracasei subsp. paracasei strains demonstrated the highest final population (>8 log cfu/ml) after 3 h of exposure at low pH. The majority of the tested strains were resistant to bile salts even after 4 h of exposure, while 5 Lb. plantarum and 7 Lb. pentosus strains exhibited partial bile salt hydrolase activity. None of the strains inhibited the growth of the pathogens tested. Variable efficiency to adhere to Caco-2 cells was observed. This was the same regarding strains' susceptibility towards different antibiotics. None of the strains exhibited β-haemolytic activity. As a whole, 4 strains of Lb. pentosus, 3 strains of Lb. plantarum and 2 strains of Lb. paracasei subsp. paracasei were found to possess desirable in vitro probiotic properties similar to or even better than the reference probiotic strains Lb. casei Shirota and Lb. rhamnosus GG. These strains are good candidates for further investigation both with in vivo studies to elucidate their potential health benefits and in olive fermentation processes to assess their technological performance as novel probiotic starters.

The microflora of must and wine consists of yeasts, acetic acid bacteria and lactic acid bacteria (LAB). The latter group plays an important role for wine quality. The malolactic fermentation carried out by LAB leads to deacidification and stabilisation of wines. Nevertheless, LAB are often associated with wine spoilage. They are mainly responsible for the formation of biogenic amines. Furthermore, some strains produce exopolysaccharide slimes, acetic acid, diacetyl and other off-flavours. In this context a better monitoring of the vinification process is crucial to improve wine quality. Moreover, a lot of biodiversity studies would also profit from a fast and reliable identification method. In this study, we propose a species-specific multiplex PCR system for a rapid and simultaneous detection of 13 LAB species, frequently occurring in must or wine: Lactobacillus brevis, Lb. buchneri, Lb. curvatus, Lb. hilgardii, Lb. plantarum, Leuconostoc mesenteroides, Oenococcus oeni, Pediococcus acidilactici, P. damnosus, P. inopinatus, P. parvulus, P. pentosaceus and Weissella paramesenteroides.

A systematic study about the intrinsic resistance of 29 strains (26 autochthonous and 3 commercial ones), belonging to Leuconostoc genus, against diverse stress factors (thermal, acidic, alkaline, osmotic and oxidative) commonly present at industrial or conservation processes were evaluated. Exhaustive result processing was made by applying one-way ANOVA, Student's test (t), multivariate analysis by Principal Component Analysis (PCA) and Matrix Hierarchical Cluster Analysis. In addition, heat adaptation on 4 strains carefully selected based on previous data analysis was assayed. The strains revealed wide diversity of resistance to stress factors and, in general, a clear relationship between resistance and Leuconostoc species was established. In this sense, the highest resistance was shown by Leuconostoc lactis followed by Leuconostoc mesenteroides strains, while Leuconostoc pseudomesenteroides and Leuconostoc citreum strains revealed the lowest resistance to the stress factors applied. Heat adaptation improved thermal cell survival and resulted in a cross–resistance against the acidic factor. However, all adapted cells showed diminished their oxidative resistance. According to our knowledge, this is the first study regarding response of Leuconostoc strains against technological stress factors and could establish the basis for the selection of “more robust” strains and propose the possibility of improving their performance during industrial processes. Fil: D'Angelo, Luisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina Fil: Cicotello, Joaquín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina Fil: Zago, Miriam. Crea-consiglio Per la Ricerca In Agricoltura E L'analisi Dell'economia Agrari; Fil: Guglielmotti, Daniela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina Fil: Quiberoni, Andrea del Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina Fil: Suárez, Viviana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina

This study aims to determine physio-chemical properties of tempoyak, characterise the various indigenous species of lactic acid bacteria (LAB) present at different stages of fermentation and also to determine the survival of selected foodborne pathogens in tempoyak. The predominant microorganisms present in tempoyak were LAB (8.88-10.42 log CFU/g). Fructobacillus durionis and Lactobacillus plantarum were the dominant members of LAB. Other LAB species detected for the first time in tempoyak were a fructophilic strain of Lactobacillus fructivorans, Leuconostoc dextranicum, Lactobacillus collinoides and Lactobacillus paracasei. Heterofermentative Leuconostoc mesenteroides and F. durionis were predominant in the initial stage of fermentation, and as fermentation proceeded, F. durionis remained predominant, but towards the end of fermentation, homofermentative Lb. plantarum became the predominant species. Lactic, acetic and propionic acids were present in concentrations ranging from 0.30 to 9.65, 0.51 to 7.14 and 3.90 to 7.31 mg/g, respectively. Genotyping showed a high degree of diversity among F. durionis and Lb. plantarum isolates, suggesting different sources of LAB. All tested Lb. plantarum and F. durionis (except for one isolate) isolates were multidrug resistant. Salmonella spp., Listeria monocytogenes and Staphylococcus aureus were not detected. However, survival study showed that these pathogens could survive up to 8-12 days. The results aiming at improving the quality and safety of tempoyak.

During collection, maple sap is contaminated by bacteria and fungi that subsequently colonize the tubing system. The bacterial microbiota has been more characterized than the fungal microbiota, but the impact of both components on maple sap quality remains unclear. This study focused on identifying bacterial and fungal members of maple sap and correlating microbiota composition with maple sap properties. A multiplex automated ribosomal intergenic spacer analysis (MARISA) method was developed to presumptively identify bacterial and fungal members of maple sap samples collected from 19 production sites during the tapping period. Results indicate that the fungal community of maple sap is mainly composed of yeast related to Mrakia sp., Mrakiella sp., Guehomyces pullulans, Cryptococcus victoriae and Williopsis saturnus. Mrakia, Mrakiella and Guehomyces peaks were identified in samples of all production sites and can be considered dominant and stable members of the fungal microbiota of maple sap. A multivariate analysis based on MARISA profiles and maple sap chemical composition data showed correlations between Candida sake, Janthinobacterium lividum, Williopsis sp., Leuconostoc mesenteroides, Mrakia sp., Rhodococcus sp., Pseudomonas tolaasii, G. pullulans and maple sap composition at different flow periods. This study provides new insights on the relationship between microbial community and maple sap quality.

Isolation and identification of the autochthonous starter from a naturally fermented meat allows control of the fermentation process and promises microbiological safety for this specialty. Thus the purpose of this study was to identify the lactic acid bacteria and coagulase-negative cocci present in a traditional Taiwanese naturally fermented ham (TNFH) and to study the microbial dynamics at different ripening stages; the approach was a combination of conventional microbiological cultivation, polymerase chain reaction-denaturing gradient gel electrophoresis and DNA sequencing. In total, twelve different strains of lactic acid bacteria and three Staphylococcus strains were identified in the TNFH samples, whereas only 5 dominant strains were observed in the TNFH samples when the DGGE as a culture-independent method was applied. The bacterial ecology on the surface of the samples was mainly characterized by the stable presence of Lactobacillus sakei and Staphylococcus saprophyticus; nonetheless Leuconostoc mesenteroides and Carnobacterium divergens were the most abundant bacteria found in the final product. These results are also agreed with the findings of the culture-independent method. In addition, Microbacterium spp., Carnobacterium spp., Enterobacter spp., Brochothrix spp., Enterococcus spp., and Bacillus spp. were also present at the beginning of the ripening, but few bacteria were found at the center of the TNFH samples during the early ripening stages. However, after 30 days of ripening, the microbial ecology at the center of the TNFH samples paralleled that of the surface. Finally, as far as we have been able to determine, our report is the first to investigate the microbiological dynamics in fermented meat products using combination of cultivation, the Harrison disc method, DGGE and DNA sequencing as the culture-dependent method. Our report is also the first to show the presence of Staphylococcus arlettae in a fermented sausage and ham product.

The diversity and dynamics of the dominant bacterial population during the manufacture and the ripening of two artisanal Pecorino Crotonese cheeses, provided by different farms, were investigated by the combination of culture-dependent and -independent approaches. Three hundred and thirty-three strains were isolated from selective culture media, clustered using Restriction Fragment Length Polymorphism and were identified by 16S rRNA gene sequencing. The results indicate a decrease in biodiversity during ripening, revealing the presence of Lactococcus lactis and Streptococcus thermophilus species in the curd and in aged cheese samples and the occurrence of several lactobacilli throughout cheese ripening, with the dominance of Lactobacillus rhamnosus species. Bacterial dynamics determined by Denaturant Gradient Gel Electrophoresis provided a more precise description of the distribution of bacteria, highlighting differences in the bacterial community among cheese samples, and allowed to detect Lactobacillus plantarum, Lactobacillus buchneri and Leuconostoc mesenteroides species, which were not isolated. Moreover, the concentration of flavour compounds produced throughout cheese ripening was investigated and related to lactic acid bacteria presence. Fifty-seven compounds were identified in the volatile fraction of Pecorino Crotonese cheeses by Gas Chromatography-Mass Spectrometry. Esters, alcohols and free fatty acids were the most abundant compounds, while aldehydes and hydrocarbons were present at low levels.

This paper focuses on the functional properties of maize sour-dough microflora selected and tested for their use as starter cultures for sour maize bread. Lactic acid bacteria and yeasts isolated from spontaneously fermented maize dough were selected based on dominance during fermentation and presence at the end of fermentation. Functional properties examined included acidification, leavening and production of some antimicrobial compounds in the fermenting matrix. The organisms previously identified as Lactobacillus plantarum, Lb. brevis, Lb. fermentum, Lb. acidophilus, Pediococcus acidilactici, Leuconostoc mesenteroides and Leuconostoc dextranicum and Saccharomyces cerevisiae were used singly and as mixed cultures in the fermentation (fermentation time: 12h at 28+/-2 degrees C) of maize meal (particle size >0.2mm). The pH fell from an initial value of 5.62-3.05 in maize meals fermented with Lb. plantarum; 4.37 in L. dextranicum+S. cerevisiae compared with the value for the control (no starter) of 4.54. Significant differences (P

Lactic acid bacteria (LAB) in different original kefir grains were first assessed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) by a culture-dependent way, and were further confirmed by DNA sequencing techniques. Results indicated that a combined method of cultivation with PCR-DGGE and subsequent DNA sequencing could successfully identify four LAB strains from three kefir grains from Taiwan (named Hsinchu, Mongolia and Ilan). Lactobacillus kefiri accounted, in the three kefir grains, for at least half of the isolated colonies while Lb. kefiranofaciens was the second most frequently isolated species. Leuconostoc mesenteroides was less frequently found but still in the three kefir grains conversely to Lactococcus lactis which based on culture-dependent isolation was only found in two of the kefir grains. It was interesting to find that all three kefir grains contain similar LAB species. Furthermore, the DGGE as a culture-independent method was also applied to detect the LAB strains. Results indicated that Lb. kefiranofaciens was found in all three kefir grains, whereas Lb. kefiri was only observed in Hsinchu kefir grain and Lc. lactis was found in both Mongolia and Ilan samples. Two additional strains, Pseudomonas spp. and E. coli, were also detected in kefir grains.

To evaluate lactic acid fermentation as a means to increase the availability of iron in carrot juice, two strains (Lactobacillus pentosus FSC1 and Leuconostoc mesenteroides FSC2), two types of carrot juice and two modes of fermentation were compared. Fermentation improved iron solubility up to 30 fold. The total mineral content and the yield of soluble iron differed between the two types of juice. Addition of pectolytic enzyme and cellulase further improved iron solubility in fermented juice by about 10%. L. pentosus FSC1 yielded the largest improvement in soluble iron, which was not simply a result of a decrease in pH. The concentration of soluble iron in Ln. mesenteroides FSC2 fermentation was linearly related to the major acids produced. Besides, the mineral inhibitor phytate was completely degraded in all the fermentations. Lactic acid fermentation strongly improves iron solubility in carrot juice. The level of improvement was strain specific and related to the produced acids rather than a simple pH effect. Composition of carrot juice and addition of viscosity-reducing enzymes also contributed to this improvement. Our study suggests that carrot juice with high mineral availability may be achieved by fermentation using selected starter cultures, substrate and process.

Lactic acid bacteria (LAB) strains, isolated from dry fermented sausages were tested as protective cultures in vacuum- or modified atmosphere-packaged sliced cooked cured pork shoulder at 4°C. The inhibitory capacity of the bacteriocins produced by Leuconostoc mesenteroides L124 and Lactobacillus curvatus L442 against different strains of Listeria monocytogenes and L. innocua were also studied. In samples inoculated with the LAB, the listeriae population decreased by about 1.5 log 10 cfu g −1 . Addition of bacteriocins in samples reduced the listeriae population below the enumeration limit (10 2 cfu g −1 ). Similar results were obtained with samples stored in modified atmosphere. Acetate concentration was increased in all samples. Thus, these lactic acid strains may be used as protective cultures to inhibit growth of L. monocytogenes or their bacteriocins in meat.

Strain NK24 was isolated from Jeot-gal and identified as a bacteriocin producer, which has bactericidal activity against Leuconostoc mesenteroides KCCM 11324. Strain NK24 was identified tentatively as Lactococcus lactis by the API test. The activity of lacticin NK24, named tentatively as the bacteriocin produced by L. lactis NK24, was detected during the mid-log growth phase, reached a maximum during the early stationary phase, and decreased after the late stationary phase. Lacticin NK24 showed a relatively broad spectrum of activity against non-pathogenic and pathogenic micro-organisms as assessed using the spot-on-lawn method. Its antimicrobial activity on sensitive indicator cells was completely destroyed by protease IX or protease XIV. The inhibitory activities of lacticin NK24 were detected during treatments up to 100°C for 30 min. Lacticin NK24 was very stable over a pH range of 2·0–9·0 and to all organic solvents examined. It demonstrated a typical bactericidal mode of inhibition against L. mesenteroides KCCM 11324. The apparent molecular mass of lacticin NK24 was estimated to be in the region of 3–3·5 kDa, which was determined by the direct detection of bactericidal activity after SDS-PAGE.

The product type was shown to strongly affect the growth rate and the composition of the spoilage lactic flora during refrigerated (4°C) storage of cooked, cured meats, sharing their processing plant environment, day of production and film packaging conditions. Growth of lactic acid bacteria (LAB) under vacuum was more prolific on the product in the order: ham>turkey breast fillet>smoked pork loin>pariza>mortadella>bacon, and ham>frankfurters, manufactured in two industrial meat plants A and B, respectively. The Lactobacillus sakei/curvatus group prevailed in all products, except the non-smoked, boiled whole-meats, i.e. cooked ham and turkey breast fillet, where Leuconostoc mesenteroides subsp.mesenteroides predominated. Lactobacillus sakei was by far the most prevalent species in smoked whole-meats, i.e. pork loin and bacon. Emulsion sausages, i.e. pariza, mortadella and frankfurters, contained a more diverse lactic flora.Leuconostoc carnosum and Lc. citreum occurred in boiled, whole-meats and emulsion sausages, respectively.Weissella viridescens was isolated from smoked meat products only. A very good correlation between the LAB growth and types and important intrinsic factors, such as the product pH, moisture, salt (brine) concentration and cooking method could be observed. When ham and frankfurters from plant B were stored in air, yeasts and mainly Brochothrix thermosphacta became important members of the spoilage association. Growth of LAB was faster in air. The presence of oxygen resulted in a replacement ofLc. mesenteroides subsp. mesenteroides by other Leuconostoc spp. in ham, and in a shift of the spoilage flora from homo- to heterofermentative LAB species in frankfurters.

An aseptic tank model system was used to study the efficacy of chlorine dioxide (ClO2) gas as a potential sanitizing agent for commercial epoxy-lined juice storage tanks. Selected spoilage micro-organisms (Lactobacillus buchneri, Leuconostoc mesenteroides, Eurotiumspp.,Penicilliumspp,Candidaspp. andSaccharomyces cerevisiae) were surface inoculated on to epoxy-coated stainless steel strips, placed in the model tank and subjected to different ClO2gas treatments. The varied treatment conditions consisted of 2–14 mg l−1ClO2gas, 50–98% relative humidity, 5–120 min exposure time, and temperatures ranging from 9–31°C.L. buchneriwas used as the target micro-organism and was found to be most resistant to selected ClO2gas treatments, followed byL. mesenteroides, followed by the yeasts and molds studied. Inactivation ofL. buchneriandL. mesenteroidesincreased with greater concentration of ClO2gas, higher holding temperature, higher relative humidity, and more exposure time. Under the conditions of this study, all the selected micro-organisms could be completely inactivated, resulting in a sterilized surface. The recommended treatments for assuring sterility were 10 mg l−1ClO2gas for an exposure time of 30 min coupled with (a) high relative humidity (>90%) and holding temperatures between 9 and 28°C, or (b) high holding temperatures (25–28°C) and relative humidity above 69%.

Minimum inhibitory concentrations (MIC) of various cleaner or sanitizer compounds were determined by a Spiral Gradient Endpoint agar diffusion method against four micro-organisms associated with spoilage of orange juice (Lactobacillus plantarum,Leuconostoc mesenteroides,Gluconobacter oxydans, andSaccharomyces cerevisiae) and against eight unidentified micro-organisms isolated from citrus fruit surfaces (two yeasts and six bacteria). Survivor curve testing was conducted on the four known micro-organisms. Compounds that were effective at the lowest concentrations were chlorine dioxide, the iodophor and quaternary ammonium compound. Dimethyldicarbonate, hypochlorite, peracetic acid and a phosphoric acid anionic compound also possessed substantial antimicrobial activity. Citric and lactic acids and d -limonene were less effective as antimicrobial compounds.

Microbiological assessment, biochemical studies and organoleptical evaluation of cheese made from pasteurized goat's milk with four different starter cultures were compared. Cheese made with starter B ( Lactococcus lactis subsp. lactis + Lactobacillus casei subsp. casei + Leuconostoc mesenteroides subsp. cremoris 6:2:2), C ( Lact. lactis subsp. lactis + Lb. casei subsp. casei + Enterococcus durans 6:2:2) or D ( Lact. lactis subsp. lactis + Lb. casei subsp. casei + E. durans + Leuc. mesenteroides subsp. cremoris 6:2:1:1) had lower ( P Streptococcus thermophilus + Lactobacillus delbrueckii subsp. bulgaricus 1:1) and this coincided with higher ( P P P E. durans in the fresh cheese. Cheeses made with starter C or D were graded higher than cheese made with starter A or B. These results suggest that mesophilic starter cultures concurrently used with E. durans might be considered appropriate for the manufacture of white-brined cheese from pasteurized goat's milk.