scholarly journals The evolution of lactic acid bacteria community during the development of mature sourdough

2009 ◽  
pp. 111-122
Author(s):  
Tanja Zugic-Petrovic ◽  
Natasa Jokovic ◽  
Dragisa Savic
Keyword(s):  
Principal Component Analysis ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Population ◽  
Principal Component ◽  
Bacterial Count ◽  
Phenotypic Characterization ◽  
Statistical Techniques ◽  
Total Bacterial Count ◽  
Genus Lactobacillus

In order to follow the composition and changes in lactic acid bacteria (LAB) population of rye flour sourdough that was continuously propagated by a repeated inoculation, sixty-two strains of LAB were isolated and characterized. The LAB were the only bacteria detected, both at the end of the second propagation step and in the stage of mature sourdough (after two weeks of continuous daily refreshment). The stable ecological system in rye sourdough could be established from the second propagation step onward. The predominant genera of LAB during the development of sourdough were lactobacilli, which were grouped in eight clusters. Heterofermentative lactobacilli were in majority in both propagation step two and a mature sourdough participating 56% and 70% of total bacterial count, respectively. The identification based on a phenotypic characterization that was carried out by using a set of 36 tests, showed that the lactobacilli contained in the two sourdough steps did not clearly belong to any known species of the genus Lactobacillus. In addition, the structure of the bacterial population were monitored by two statistical techniques (Hierachical Cluster Analysis and Principal Component Analysis), being applied to phenotypical characteristics of the isolates.

scholarly journals Profiling and antibiotic resistance of lactic acid bacteria isolated from commercial aMasi samples

2020 ◽  
Author(s):  
◽  
Yovani Pillay
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Food Safety ◽  
Lactic Acid Bacteria ◽  
South African ◽  
Bacterial Population ◽  
Principal Component ◽  
Antibiotic Resistant ◽  
Food Grade ◽  
Resistant Genes

aMasi is traditionally fermented milk that constitutes part of the South African heritage and is regarded as a supplementary staple food. Its inclusion into the South African Food Based Dietary Guidelines has led to the encouraged consumption of this product. Given the fact that aMasi is a rich source of lactic acid bacteria (LAB), such bacteria are of economic importance to the food, feed and pharmaceutical industries. The main concern regarding food safety is ability to acquire and disseminate antibiotic-resistant genes. Although LAB bility of resistance genes to human and animal opportunistic and pathogenic bacteria which could make treatment of bacterial infections more complex to treat in the future. Numerous reports globally, have documented antibiotic resistance among LAB isolated from commercial dairy and pharmaceutical products over the last decade. Therefore, the aim of this study was to determine if LAB isolated from commercial aMasi samples harbour antibiotic-resistant genes. To achieve this aim, the total bacterial population and LAB population of 10 aMasi samples were surveyed using culture-dependent techniques and the proportional prevalence of LAB to the total bacterial population were determined by using a 100% stacked-column. In all 10 samples, LAB was the predominating population ranging from 87.44% to 99.77%. A total of 30 LAB isolates were characterised after isolation and sequencing of 16S rDNA of these isolates showed that LAB were Leuconostoc pseudomesenteroides and Leuconostoc mesenteroides with two isolates being identified as Lactococcus lactis CP028160.1. The relationship between the growth of LAB and selected physicochemical properties (pH, titratable acidity, water activity (aw), moisture content, fat content and estimation of reducing sugars (lactose)) were determined using principal component analysis (PCA) and classification and regression tree (CART) to illustrate the likelihood of LAB present in aMasi samples based on LAB count and pH. From the PCA results, approximately 75.25% of variances in the data were retained by the first three principal components (PCs). The first principal component (PC1) had accounted for the highest total variance of 33.16%. PC1 increased with an increase in lactic acid % and aw, whilst it negatively correlated with LAB count, moisture % and lactose (mg/25ml lactose·H2O). The results showed an increase in LAB count with an increase in moisture % and lactose (mg/25ml lactose·H2O) whilst, LAB count had decreased with an increase in lactic acid % and aw. Moreover, pH and fat % had no effect on PC1, high LAB counts were observed for samples 6 and 7 whist low LAB counts were observed for samples 9 and 10. On the other hand, PC2 had accounted for approximately 27.53% of the total variance. PC2 increased with an increase in fat % and lactose (mg/25ml lactose·H2O), whilst it negatively correlated with LAB count and pH. It was observed that the growth of LAB had increased with an increase in pH, whilst it decreased with an increase in fat % and lactose (mg/25ml lactose·H2O). Moreover, lactic acid %, aw and moisture % had no effect on PC2. High LAB counts were observed for samples 7 and 8 and low LAB counts were observed for samples 2 and 4. Nine out of the 30 LAB isolates were selected due to these isolates having a different GenBank Accession number and were subjected to antibiotic susceptibility testing using the disc diffusion method against a total of 11 antibiotics. Most of the LAB isolates exhibited multiple resistance towards some of the most commonly used antibiotics as well as last-resort antibiotics. All the isolates showed high levels of resistance towards vancomycin, colistin sulphate, fosfomycin and pipemidic acid except for Lactococcus lactis CP028160.1 which was susceptible to vancomycin. All isolates were susceptible to tetracycline and erythromycin whilst eight out of nine isolates were susceptible to chloramphenicol with seven out of nine isolates being susceptible to ampicillin. Furthermore, the isolates had displayed intermediate resistance mainly towards kanamycin and streptomycin. The present study showed that multiple antibiotic resistance is prevalent in different species of starter culture strains, which may pose a food safety concern. LAB that exhibit phenotypic resistance to antibiotics should also be evaluated on a molecular level to monitor their resistance. The presence of such a variety of expressed AR genes in probiotic isolates is a worrying trend. The impact of the interactions of these bacteria with pathogenic strains and their transfer of these AR genes is yet to be assessed. Furthermore, antibiotic sensitivity is an important criterion in the safety assessment for the evaluation of food-grade and potential food-grade LAB.

Evolution of anthocyanin profile from grape to wine

OENO One ◽  
2010 ◽  
Vol 44 (3) ◽  
pp. 167
Author(s):  
Margherita Squadrito ◽  
Onofrio Corona ◽  
Giacomo Ansaldi ◽  
Rocco Di Stefano
Keyword(s):  
Principal Component Analysis ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Polyphenol Oxidase ◽  
Alcoholic Fermentation ◽  
Principal Component ◽  
Malolactic Fermentation ◽  
Great Care ◽  
Pca Analysis ◽  
Anthocyanin Profile

<p style="text-align: justify;"><strong>Aims</strong>: This study aimed at acquiring knowledge of the evolution of anthocyanins from grape to wine and the possibility of deducing the varietal origin of a wine from its anthocyanin profile.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The anthocyanin « fingerprint », or profile, of a series of autochthonous Sicilian accessions and their respective young wines was determined by HPLC-DAD in 2008. Data were evaluated by taking into account the evolution of the percentages of side-ring dioxygenated and tri-oxygenated anthocyanins, the ratio between acetylated and p-coumaroylated derivatives, and the principal component analysis (PCA) results. From grape to the end of alcoholic fermentation, the percentages of 3-glucosides of cyanidin, peonidin, delphinidin and p-coumaroylglucosides decreased, whereas those of malvidin-3-glucoside, acetylated derivatives and, in some cases, petunidin-3-glucoside increased. In many but not all wines, after malolactic fermentation, the percentages of p-coumaroylated derivatives decreased further and those of cyanidin- 3-glucoside and acetylated derivatives increased ; less variation was observed in malvidin-3-glucoside values.</p><p style="text-align: justify;"><strong>Conclusions</strong>: From grapes to young wines, the anthocyanin profiles varied mainly because of the activity of polyphenol oxidase (PPO), yeasts and lactic acid bacteria. However, they were substantially retained in wines from varieties in which tri-oxygenated side-ring anthocyanins prevailed, but were dramatically different from the respective grapes in wines from varieties rich in di-oxygenated anthocyanins, or in which the di-oxygenated forms prevailed over the tri-oxygenated ones. PCA analysis confirmed these findings.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: Only in varieties in which the anthocyanin profile of grapes is characterized by low percentages of dioxygenated side-ring forms is it possible to gain information about the varietal origin of a young wine by comparing the profiles of both grape and wine. However, great care is required.</p>

Microbiological Quality of Rabbit Meat

2004 ◽  
Vol 67 (5) ◽  
pp. 966-971 ◽  
Author(s):  
JOSE M. RODRÍGUEZ-CALLEJA ◽  
JESÚS A. SANTOS ◽  
ANDRÉS OTERO ◽  
MARÍA-LUISA GARCÍA-LÓPEZ
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Meat Production ◽  
Total Bacterial Count ◽  
Indicator Organisms ◽  
Ph Values ◽  
Rabbit Meat ◽  
Microbial Groups

World rabbit meat production is estimated to be over 1 million tons, and Spain is the third largest producer. Although rabbit meat is marketed and consumed worldwide, information on microbiological quality is very scarce. Here, we report indicator organisms, spoilage flora, sensory quality, and some physicochemical traits of 24 h postmortem chilled rabbit carcasses and prepackaged rabbit meat stored chilled in air for 0 to 3 days at the retail level. The mean total bacterial count (4.01 ± 0.48 log CFU/g) for carcasses dressed at a small abattoir by a manual process was significantly lower (P &lt; 0.05) than that (4.96 ± 0.90 log CFU/g) for carcasses dressed at a large abattoir in automated slaughter lines. Both groups of carcasses had mean pH values of 5.98. The dominant contaminants on carcasses from the small abattoir were Pseudomonas, lactic acid bacteria, and yeasts. These microorganisms and Brochothrix thermosphacta were dominant on carcasses from the large abattoir. On prepacked hind legs (pH 6.26 ± 0.18) stored at −1 to + 1° C (supermarket 1), mean aerobic mesophilic count was 5.87 ± 1.03 log CFU/g, and the major microbial groups were Pseudomonas, yeasts, lactic acid bacteria, and B. thermosphacta. On prepacked whole carcasses (pH 6.37 ± 0.18) displayed at −1 to + 5° C (supermarket 2), mean aerobic mesophilic count was 6.60 ± 1.18 and the same microbial groups were dominant. Relative Escherichia coli incidence was supermarket 2 &gt; large abattoir &gt; supermarket 1 &gt; small abattoir. Overall, low numbers of coliforms, Enterobacteriaceae, psychrotrophic clostridia, coagulase-positive staphylococci, and molds were found. Sensory scores, pH values, and L-lactic acid content differentiated fresh carcasses from retail samples. Data obtained suggest that the microflora of chilled rabbit meat are different from those found on the meat of other animals.

scholarly journals USE OF LACTIC ACID BACTERIA IN PEANUT SEED TREATMENT

2020 ◽  
Vol 1 (1) ◽  
pp. 20-22
Author(s):  
Hoai Huong Nguyen ◽  
Bich Tram Tran Le
Keyword(s):  
Heat Treatment ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Seed Treatment ◽  
Bacterial Count ◽  
Positive Control ◽  
Culture Broth ◽  
Total Bacterial Count ◽  
Conventional Agriculture ◽  
Aspergillus Sp

Three lactic acid bacteria (LAB) strains, Lactobacillus sp. L5, Lactobacillus sp. L3, Lactobacillus sp. L2N, isolated from Vietnamese traditional Nem chua grew well in cabbage broth supplemented with 12 g/L glucose and 15 g/L peptone and showed inhibitory activity ranging from 40% to 44% against Aspergillus sp. CDP isolated from mould contaminated peanuts, while Daconil 75WP – a fungicide compounds – as a positive control showed only 26.9%. LAB strains also displayed Indole-acetic acid (IAA) production, P-solubilization and biofilm formation. Soaking seeds in separate cabbage based culture broth of three LAB strains with/without heat treatment and mixed culture broths at the ratio 1:1:1 with the total bacterial count 108cfu/mL exhibited the antifungal activity of mixed cultures in both cases with or without bacterial culture heat treatment. Soaking seeds in the same mixed bacterial cultures without heat treatment increased seed germination and vigor index, compared to the control seeds without any treatment and those treated with fungicide compounds. After 75 days of sowing the length and total fresh weight of LAB-treated peanut plants increased by 22.4 % and 99.6%, higher than that of Daconil treated ones with only 15.9% and 59.7% increment. Moreover, the fresh yield of peanut pegs increased 2.5 times, compared to those of untreated and Daconil treated seeds. This study suggested that seed treatment with LAB is a novel technology towards organic farming to replace fungicide used in conventional agriculture.

scholarly journals Impact of Freezing on the Microbiological Quality and Physical Characteristics of Buffalo Mozzarella Cheese

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3502
Author(s):  
Loredana Biondi ◽  
Andrea Fulgione ◽  
Federico Capuano ◽  
Morena Nappa ◽  
Angelo Citro ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Physical Properties ◽  
Dairy Products ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Buffalo Milk ◽  
Total Bacterial Count ◽  
Mozzarella Cheese ◽  
Preliminary Results

Buffalo Mozzarella cheese from Campania is one of the most worldwide appreciated Italian dairy products. The increased demand for buffalo dairy products and the limited availability of the finest buffalo milk has prompted the diffusion of illicit practices, such as the use of milk, curd, or other products that are frozen or bought at low cost. The aim of this research was to provide preliminary results about the trend of the microbial communities of buffalo milk, curd and Buffalo Mozzarella cheese, during freezing storage of eleven months. At the same time, the alterations of physical properties and the presence of the molecular marker “γ4-casein”, have been investigated. The results showed that freezing reduced the concentrations of the total bacterial count, Enterobacteriaceae, coliforms, Escherichia coli and yeasts in fresh milk and, the concentrations of the total bacterial count, coliforms, lactic acid bacteria and yeasts in mature curd. In the finished product, no notable decreases were observed, except for lactic acid bacteria. About the γ4-casein, no increase was observed in all matrices. These preliminary results allow us to conclude that the freezing process if properly carried out, does not compromise the microbiological quality and the physical properties of the Buffalo Mozzarella cheese.

scholarly journals Diversity of microorganisms in the traditional Slovak cheese

10.5219/1061 ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 532-538
Author(s):  
Miroslava Kačániová ◽  
Simona Kunova ◽  
Elena Horská ◽  
Ľudmila Nagyová ◽  
Czeslaw Puchalski ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Count ◽  
Raw Milk ◽  
Lactobacillus Helveticus ◽  
Coliform Bacteria ◽  
Plate Count ◽  
Total Bacterial Count ◽  
Organoleptic Characteristics ◽  
Microbiological Methods

The aim of the present study was to describe the microbial groups of the traditional Slovak cheese Parenica during rippening. The microbial group included the total bacterial count, coliform bacteria, enterococci, lactic acid bacteria, and microscopic filamentous fungi, which may affect the organoleptic characteristics of this product. A total of 42 cheese samples were collected from four different farms during three months. The total bacterial counts were cultivated on Plate count agar at 30 °C, lactic acid bacteria (LAB) on MRS, APT and MSE at 37 °C, coliform bacteria on VRBL at 37 °C. Gram-positive and Gram-negative isolates were identified by MALDI-TOF MS profiling. Bacillus sp. and Enterococcus faecium were the most frequently identified species of bacteria. Candida kefyr was the most distributed yeast according to microbiological methods. Lactic acid bacteria group was represented by Lactobacillus helveticus, L. jensenii, L. alimentarius, L. crispatus, L. curvatus, L. fermentum, L. suebicus, L. delbrueckii ssp. lactis, L. paracasei ssp. paracasei, Lactococcus lactis ssp. lactis, Leuconostoc lactis and Le. mesenteroides ssp. mesenteroides . This report describing the indigenous microbiota of the traditional raw milk cheeses from Slovakia. Our results provide useful information on occurrence of valuable microbial strain for the industrialization of producing of the traditional dairy products in Slovakia.

78. A Study of the Quantitative Changes in the Microbiological Flora of Sweet-Cream Salted Butter of Good Keeping Quality when held at 15° F. for a Period of Two to Eight Months

1934 ◽  
Vol 5 (2) ◽  
pp. 137-143 ◽  
Author(s):  
M. Grimes ◽  
A. J. Hennerty
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Titratable Acidity ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Noticeable Increase ◽  
Keeping Quality ◽  
Quantitative Changes ◽  
Micro Organisms ◽  
Microbiological Flora

1. Data, taken over a period of eight months, are presented, concerning the quantitative changes which take place in the microflora of sweet-cream salted cold-stored butter of good keeping quality.2. Tables showing the influence of varying periods of cold storage on the development of acidity, total bacterial count, yeasts, moulds, gelatin liquefying bacteria and types of micro-organisms in forty-nine churnings of butter cold stored at 15° F. are given.3. There was a slight increase in the titratable acidity.4. There was a noticeable increase of the yeast count, in many cases without apparently injuring the keeping quality.5. The numbers of Oidium lactis present tended to decrease.6. The following types of bacteria persisted in the sweet-cream salted butter in decreasing numbers: (a) various types of micrococci; (b) lactic acid bacteria of non-coagulating and acid coagulating types, including “slow” varieties of Str. lactis; (c) acid with coagulation and gas; (d) rennet digesting; (e) alkaline-forming; (f) alkaline digesting.

EFFECT OF STORAGE TEMPERATURE ON THE MICROFLORA OF IRRADIATED AND NONIRRADIATED VACUUM-PACKAGED PETRALE SOLE FILLETS

1968 ◽  
Vol 31 (8) ◽  
pp. 231-236 ◽  
Author(s):  
Gretchen A. Pelroy ◽  
John P. Seman
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Storage Temperature ◽  
Radiation Treatment ◽  
Bacterial Count ◽  
Total Bacterial Count ◽  
Polyethylene Bags ◽  
Aerobic Flora ◽  
Storage Temperatures ◽  
Coagulase Positive Staphylococcus

Petrale sole fillets that were vacuum packaged in mylar-polyethylene bags were irradiated at 0.0, 0.1, 0.2, and 0.3 megarad and stored at 0.5, 3.3, 5.6, 7.8, 10.0, 15.6, and 22.2 C. The fish were monitored throughout storage for spoilage, total bacterial count, coliform count, enterococcus count, and the presence of coagulase-positive Staphylococcus. Generic changes in the aerobic flora were determined by the identification of nearly 14,000 microbial isolates. The predominant spoilage flora of the irradiated fish stored at all the temperatures were lactic acid bacteria. The predominant flora at the time of spoilage of the nonirradiated fish stored at 5.6 C and below was Pseudomonas. When the nonirradiated fish was stored above 5.6 C, the predominant spoilage flora was lactic acid bacteria. Coliforms and enterococci showed growth at the higher storage temperatures but were suppressed by the radiation treatment. No coagulase-positive Staphylococcus were found in any of the irradiated samples.

scholarly journals Galactooligosaccharide effects as prebiotic on intestinal microbiota of different fish species

2019 ◽  
Vol 14 (3) ◽  
pp. 266-278
Author(s):  
Seyed Hossein Hoseinifar ◽  
Hien Van Doan ◽  
Ghasem Ashouri
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gut Microbiota ◽  
Intestinal Microbiota ◽  
Bacterial Communities ◽  
Bacterial Count ◽  
Control Group ◽  
Total Bacterial Count ◽  
The Caspian Sea ◽  
Caspian Roach

Manipulation of the gut microbiota toward potentially beneficial bacteria (probiotics) has beneficial effects on fish physiology and health. The effects of prebiotics on gut microbiota are species specific. The present study aimed at investigation of the effects of galactooligosaccharide (GOS) as prebiotic on intestinal microbiota of Caspian roach and Caspian white fish fingerlings. which are among the most economically valuable species in the Caspian Sea. The study was conducted in a completely randomized design with two set of experiment each of them include three treatments in triplicates in which 0 (control), 1 and 2% GOS were used in diet for 6 weeks. At the end of the period, changes in the intestinal microbiota, including total bacterial count, lactic acid count and lactic acid bacteria (LAB) levels and dominance of LAB in the intestinal microbiota, were measured by culture-based method. Dietary GOS had no significant effect on total bacterial count in both species (P < 0.05). The LAB levels in the intestinal microbiota in the treatments fed with prebiotics was significantly higher than the control group (P < 0.05). LAB bacteria showed the highest increase and dominance in treatments fed with 2% GOS. Also, the highest ratio of lactic acid bacteria to the total number of viable bacteria was observed in the treatment with 2% GOS treatment (P < 0.05). The results of this study indicated the possibility of alterations in the bacterial communities of Caspian roach and Caspian white fish fingerlings gut toward beneficial bacterial communities using GOS as prebiotic.

scholarly journals Suitability Analysis of 17 Probiotic Type Strains of Lactic Acid Bacteria as Starter for Kimchi Fermentation

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1435
Author(s):  
Hee Seo ◽  
Jae-Han Bae ◽  
Gayun Kim ◽  
Seul-Ah Kim ◽  
Byung Hee Ryu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Growth Rates ◽  
Principal Component ◽  
Fermented Foods ◽  
Suitability Analysis ◽  
Moderate Growth ◽  
Health Promoting ◽  
Highly Correlated ◽  
Type Strains

The use of probiotic starters can improve the sensory and health-promoting properties of fermented foods. This study aimed to evaluate the suitability of probiotic lactic acid bacteria (LAB) as a starter for kimchi fermentation. Seventeen probiotic type strains were tested for their growth rates, volatile aroma compounds, metabolites, and sensory characteristics of kimchi, and their characteristics were compared to those of Leuconostoc (Le.) mesenteroides DRC 1506, a commercial kimchi starter. Among the tested strains, Limosilactobacillus fermentum, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Ligilactobacillus salivarius exhibited high or moderate growth rates in simulated kimchi juice (SKJ) at 37 °C and 15 °C. When these five strains were inoculated in kimchi and metabolite profiles were analyzed during fermentation using GC/MS and 1H-NMR, data from the principal component analysis (PCA) showed that L. fermentum and L. reuteri were highly correlated with Le. mesenteroides in concentrations of sugar, mannitol, lactate, acetate, and total volatile compounds. Sensory test results also indicated that these three strains showed similar sensory preferences. In conclusion, L. fermentum and L. reuteri can be considered potential candidates as probiotic starters or cocultures to develop health-promoting kimchi products.

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