scholarly journals Isolation and Characterization of Lactic Acid Bacteria From Milk and Their Effects on the Pathogenic Bacteria

2020 ◽  
Vol 8 (4) ◽  
pp. 189-200
Author(s):  
Ciamak Ghazaei ◽  
Keyword(s):  
Lactic Acid ◽  
Minimum Inhibitory Concentration ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Cow Milk ◽  
Milk Samples ◽  
Isolation And Characterization ◽  
Antibiotic Susceptibility Test

Background: Probiotics are “live microbial cells” that are beneficial for human and animal health. Lactobacilli are such a diverse group of bacteria with similar metabolic and physiological characteristics, and constitute important and beneficial gut microflora. During carbohydrate fermentation, lactobacilli produce lactic acid as an end product in metabolism. Hence, lactobacilli have high significance to be used as probiotics in the food industry, because of their acidifying properties. Also, lactobacilli are considered “safe”, owing to their ubiquitous presence in the food. Many researchers provided evidence for the presence of lactobacilli in milk sources. Thus, the present study aimed to isolate and characterize different lactobacilli strains from milk sources and analyze their “probiotic potential”. Materials and methods: Forty-one lactobacilli isolates were obtained from raw cow milk. Then, the strains were characterized by morphological identification and biochemical tests. Besides, probiotic potentials were evaluated with the bile tolerance test, antibiotic susceptibility test, and determining suitable pH for the optimal growth of lactobacilli. The lactobacilli isolates were also analyzed for their probiotic characteristics and the release of antimicrobial substances. Their antimicrobial activities against pathogenic strains were assessed by determining the minimum inhibitory concentration, with the help of agar diffusion methods. Results: From 50 milk samples, 41 lactobacilli isolates were obtained, out of which five lactobacilli strains were identified as Lactobacillus casei, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus acidophilus, and Lactobacillus lactis. Moreover, 35 isolates showed an inhibitory effect. These strains were able to survive and grow in 0.5% to 2.5% bile salt concentrations. Lactic acid bacteria were susceptible to antibiotics, and 35 isolates obtained from raw milk showed an inhibitory effect against pathogenic bacteria. The observed minimum inhibitory concentration ranged from 50 to 100 µL and varied between the different pathogens. Conclusion: Out of 41 Lactobacillus isolates obtained from cow milk samples, 35 were identified with probiotic characteristics. Hence, this study highlighted the novel probiotic bacteria and validated the antimicrobial properties of the Lactobacillus spp against pathogenic bacteria.

scholarly journals Determination of minimum inhibitory concentrations of lactic acid bacteria and other antagonist microorganisms

2021 ◽  
Vol 291 ◽  
pp. 02006
Author(s):  
Svetlana Noskova ◽  
Stanislav Sukhikh ◽  
Olga Babich ◽  
Olga Bulgakova
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Minimum Inhibitory Concentration ◽  
Lactic Acid Bacteria ◽  
Pseudomonas Syringae ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Acetobacter Aceti ◽  
Minimum Concentration ◽  
Minimum Inhibitory Concentrations

Minimum inhibitory concentrations of lactic acid bacteria and other antagonist microorganisms isolated from natural sources of Kaliningrad region (soil, water bodies, plant objects) were determined. It was shown that the minimum inhibitory concentration of Pediococcus pentosaceus metabolites against Escherichia coli is 1.5·107 CFU/ml; Pseudomonas chlororaphis metabolites have no inhibitory effect against the test strain of Escherichia coli under study. It was found that Pediococcus damnosus metabolites adversely affect the growth of Escherichia coli, but at a concentration of 1.5·107 CFU/ml after 6-24 hours of cultivation. For metabolites isolated by Lactobacillus casei, the characteristic minimum inhibitory concentration with respect to the studied Escherichia coli strain is 1.5-107 CFU/ml, and for metabolites isolated by Lactobacillus fermentum, the minimum inhibitory concentration with respect to the studied Escherichia coli strain is 1.5·105 CFU/ml. At a concentration of Bacteroides hypermegas (Megamonas hypermegale) metabolites equal to 1.5·106 CFU/ml, an optical density lower than that of the control is observed. The minimum concentration of Pseudomonas syringae metabolites inhibiting Escherichia coli culture growth is 1.5-107 CFU/ml. For the metabolites Acetobacter aceti and Psychrobacter urativorans, the concentration of 1.5·107 CFU/ml is the lowest to inhibit the growth of Escherichia coli.

scholarly journals Nisin and ε-poly-L-lysine as natural antimicrobials towards spoilage-associated Lactobacillus plantarum

2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Fernanda Cristina Kandalski Bortolotto ◽  
Maria Helena da Rosa Farfan ◽  
Nathalia Cristina Kleinke Jede ◽  
Gabriela Maia Danielski ◽  
Renata Ernlund Freitas de Macedo
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Minimal Bactericidal Concentration ◽  
Natural Antimicrobials ◽  
Food Preservatives ◽  
Spoilage Bacteria ◽  
Mass Spectrometry Identification

ABSTRACT: Sausages are highly susceptible to microbial spoilage. Lactic acid bacteria (LAB) is the main group of spoilage bacteria in vacuum packed cooked sausages. To control microbial growth natural antimicrobials have been used as food preservatives. The aim of this study was to identify strains of lactic acid bacteria isolated from spoiled commercial Calabresa sausages and use them in an in vitro challenge with the natural antimicrobials, nisin (NI) and ε-poly-L-lysine (ε-PL). Mass spectrometry identification of LAB isolated from sausages using MALDI-TOF revealed a predominance of L. plantarum in the LAB population. RAPD-PCR of L. plantarum strains showed four different genetic profiles. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of NI and ε-PL, alone and in combination, against a pool of different profiles L. plantarum were determined. MIC of NI and ε-PL were 0.468 mg/ L and 75 mg/ L; respectively, whereas MBC of NI and ε-PL were 12.48 mg/L and 150 mg/L, respectively. The combined effect of NI and ε-PL was determined using concentrations at 1/4 and 1/8 of individual MICs. Synergistic effect was confirmed at both concentrations showing a fractional inhibitory concentration index of 0.5 and 0.2, respectively. The combination of NI and ε-PL at a small concentration of 0.05 mg/L and 9.375 mg/L, respectively, showed inhibitory effect towards spoilage L. plantarum Results show the potential of the combined use of NI and ε-PL to control sausage spoilage-associated with lactobacilli.

scholarly journals LACTIC ACID BACTERIA AS BIOACTIVE POTENTIAL AGAINST SELECTED RESISTANCE CANDIDA SPECIES AND PATHOGENIC BACTERIA

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Chiamaka Linda Mgbechidinma ◽  
Caleb Oladele Adegoke ◽  
Samuel Temitope Ogunbanwo
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Plantarum ◽  
Candida Species ◽  
Pathogenic Bacteria ◽  
Fermented Milk ◽  
Diffusion Method ◽  
Antibiotics Resistance ◽  
Zone Of Inhibition ◽  
Antibiotic Susceptibility Test

This research focused on the isolation and antagonistic action of Lactic Acid Bacteria (LAB) against certain antibiotics resistance disease causing bacteria and fungai. Antibiotic resistance is an increasing problem amid humans and animals in land-dwelling or marine environments hence making treatment of infections difficult. Antibiotic susceptibility test for bacteria pathogen was performed using the disc diffusion method while antifungal susceptibility and antimicrobial activity of LAB were carried out using agar well diffusion method. All the pathogenic bacteria used as indicator organisms were multiple antibiotics resistance and 100 percent resistance to gentamycin and pefloxacillin with the exception of Staphlococcus aureus. Candida species was 100 percent resistance to Ketoconazole, fluconazole and miconazole. Twenty-two LAB isolates were gotten from fermented milk and milk products. The isolates were identified as Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus delbrueckii, Leuconostoc mesenteriodes, Lactobacillus casei, Lactobacillus brevis, Lactobacillus acidophilus, Lactococcus lactis, Streptococcus thermophilus, Lactobacillus helveticus and Lactobacillus rhamnosus. LAB produced lactic acid to varying concentrations, having its production peak (1.80g/L) at 48 h of incubation by Lactobacillus plantarum. Lactobacillus fermentumNU2 produced the highest quantity of diacetyl (2.80g/L) while Lactobacillus acidophilusGO8 and Lactococcus lactisGO9 produced the highest amount of hydrogen peroxide (0.030g/L) at 48 h of incubation. Lactobacillus plantarumGO16 inhibited Bacillus cereus while Lactobacillus acidophilusGO8 inhibited Staphylococcus aureus with 28 mm zone of inhibition. Lactobacillus plantarumNU1 and Lactobacillus plantarumGO16 inhibited Candida albican with 25 mm zone of inhibition. LAB can be used as probiotics in preventing infections caused by Candida species and pathogenic bacteria. Keywords: Lactic Acid Bacteria, Fermented milk, antibiotics resistance, antagonistic activity, pathogens.

scholarly journals Isolation and Characterization of Lactic Acid Bacteria Isolated from Fermented Food of North-West Himalayas

2021 ◽  
Author(s):  
Heenu Sharma ◽  
Jasveen Bajwa
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
Biochemical Characterization ◽  
Antagonistic Activity ◽  
Fermented Food ◽  
Fermented Foods ◽  
North West ◽  
The North ◽  
Isolation And Characterization

Lactic acid bacteria (LAB) are ubiquitous and are one of the major microbial groups involved in the fermentation of various types of food. They are the most dominant microbes present in milk or milk products and fermented foods where they play vital roles in both the manufacturing and ripening processes. Kaladhi is one of the traditional fermented products of the North-West Himalaya region. It is a hard and dry cheese. In our research, a total of 9 isolates was isolated and was evaluated on the basis of preliminary characterization viz. morphological as well as biochemical characterization and was examined for their antagonistic activity against following pathogens. On the basis of their maximum antagonistic potential against food-borne pathogenic bacteria, isolate K1 is characterized by 16S rRNA sequencing. The isolate was identified as Lactobacillus paracasei subsp. Tolerans strain NBRC 15906 K1|MN814072|.This research was aimed to study the unexplored microflora of Kaladhi and to determine its probiotic potential.

scholarly journals Carbohydrate Fermentation Profile and Physiological Studies of Lactic Acid Bacteria from Native Raw Cow Milk

2020 ◽  
pp. 83-93
Author(s):  
A. B. Adediran ◽  
S. Aforijiku
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Genomic Analysis ◽  
Proximate Analysis ◽  
Lactobacillus Bulgaricus ◽  
Cow Milk ◽  
Milk Samples ◽  
Probiotic Potential ◽  
Test Kit ◽  
Physiological Studies

The aim of this study was to identify and evaluate the physiological studies of lactic acid bacteria from native raw cow milk. Cow milk samples were collected purposively from four different locations in Ibadan. The proximate analysis, pH and acidity of the milk samples were examined using standard procedures. Lactic acid bacteria (LAB) were isolated, characterized, and identified using both morphological, biochemical test, and Analytical profile index (API) system. The identified LAB were subjected to various physiological conditions such as growth at different temperature (15, 30, 45°C), pH (4, 6, 8) and NaCl concerntrations (4, 6, and 8%).The heterotrophic counts ranged between 3.1 ×107to 4.2 ×107CFU/mL and lactic acid bacteria counts ranged from 2.2× 107 to 3.8 × 107 CFU/mL. Thirty-five LAB isolates were randomly picked and identified as Lactobacillus (57.15%), Streptococcus (14.29%), Leuconostoc (8.57%), Pediococcus (8.57%), Lactococcus (5.71%) and Enterococcus (5.71%). The LAB isolates were further identified as Lactobacillus plantarum, Leuconostoc mesenteriodes, Lactococcus lactis, Lactobacillus acidiophilus and Lactobacillus bulgaricus based on API 50 test kit, and were able to grow at different physiological paramaters. This study shows that Lactobacillus strains isolated from raw cow milk had better physiological attributes. These LAB could be recommended for further assessment such as evaluation of probiotic potential properties and genomic analysis.

Isolation, identification and characterization of Lactobacillus plantarum from camel milk and its antagonist effect against diarrheal bacteria.

2018 ◽  
Vol 30 (4) ◽  
pp. 283 ◽  
Author(s):  
Meriem Toualbia, Abd ElKader Delmi Bouras ◽  
Malika Koiche, Mohamed Kerkoud
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Plantarum ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Bioactive Molecules ◽  
Camel Milk ◽  
Fecal Samples ◽  
Infantile Diarrhea ◽  
Rdna Sequencing

The main objective of this study is to define probiotic bacteria efficiency against bacterial infantile diarrhea. Lactic acid bacteria (LAB) was used as a natural resource and extracted of camel milk from southern Algeria. The isolation was followed by molecular identification using the 16S rDNA sequencing method. One hundred and fifty fecal samples were collected over 18 months from children suffering from diarrhea and aged 2 years or under. Identification results reveal the isolated lactic bacteria as Lactobacillus plantarum. In the other side, a total of 120 fecal samples were positive for bacterial growth, these pathogenic bacteria were identified as: Escherichia fergusonii (92%), Salmonella enterica subsp. Diarizonae (7.33%) and Proteus mirabilis (0.66%). The inhibitory effect study of lactic acid bacteria on pathogenic bacteria shows varying effects of L. plantarum in relation to the various pathogenic isolates, mentioning that the most important effect was expressed against Escherichia fergusonii with 22 mm. All the results allow us to classify that camel's milk is a natural source rich in lactic acid bacteria, in particular L. plantarum, with an inhibitory ability against the pathogenic bacteria responsible for diarrhea. Therefore L. plantarum produces bioactive molecules responsible for this effect.

scholarly journals ISOLATION AND CHARACTERIZATION OF UNIQUE FRUCTOPHILIC LACTIC ACID BACTERIA FROM DIFFERENT FLOWER SOURCES.

2020 ◽  
Vol 51 (2) ◽  
pp. 508-518
Author(s):  
G. M. Saleh
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Enterococcus Faecium ◽  
Pathogenic Bacteria ◽  
Lactobacillus Brevis ◽  
Nerium Oleander ◽  
Dual Culture ◽  
Bacterial Strains ◽  
Convolvulus Arvensis ◽  
Isolation And Characterization

This study was aimed to investigate Lactic acid bacteria (LAB) that contain an important group of bacterial strains such as fructophilic lactic acid bacteria that usually isolated from fructose rich niches. These groups of bacteria have been considered as probiotics, especially in animal applications. In this study these bacteria were isolated from 6  Plant sources (flowers) such as: Convolvulus arvensis, Hibiscus rosa-sinensis , Nerium oleander, Rosa rugosa, Tagetes erecta and Zinnia elegans. The bacterial isolates were identified by morphological and molecular methods through the detection of 16SrRNA gene. Carbohydrate fermentation profile as well as their antibacterial activity using the dual culture overlay assay was also detected. The results revealed that 5 types of different lactic acid bacteria were isolated included: Fructobacillus fructosus, Lactobacillus kunkeei, Enterococcus durans, Enterococcus faecium , and  Lactobacillus brevis. These isolates showed variety in fermentation of carbohydrates. Also, all isolates exhibit inhibition effect against pathogenic bacteria (Staphylococcus auresو Pseudomonas aeruginosa) except Enterococcus faecium which showed no effect it.

scholarly journals RAW COW MILK AS A POTENTIAL SOURCE OF BENEFICIAL LACTIC ACID BACTERIA (LAB)

2021 ◽  
Vol 4 (1) ◽  
pp. 37-39
Author(s):  
Kokila Muniyandi ◽  
Ganesh Punamalai ◽  
Nandhini Chandrasekaran ◽  
Yoganathan Kamaraj
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Raw Milk ◽  
Cow Milk ◽  
Isolation And Identification ◽  
Good Source ◽  
Milk Samples ◽  
Naturally Occurring ◽  
Potential Source ◽  
The Many

Milk itself is also considered to be one of the nature habitats of the LAB, It contains the many other nutrients and including protein and lactose. The aim of the research was a isolation and identification of naturally occurring lactic acid bacteria from cow raw milk. A total of ninety isolates of lactic acid bacteria were collected of which seven genera belonging to Lactobacillus (29.32%), Lactococcus (23.68%), Leuconostoc (21.09%), Streptococcus (12.09%), Aerococcus (9.09%), Pediococcus (17.09%) and Enterococcus (12.09%) were identified. Leuconostoc, Enterococcus, Pediococcus, Lactococcus, and Aerococcus were cocci and rod shape of Lactobacillus. In the current study, Lactobacillus (29.32%) was the main genera of lactic acid bacteria identified from cow raw milk samples. We can conclude from this research that raw cow milk is a good source of healthy lactic acid bacteria.

scholarly journals Isolation and characterization of lactic acid bacteria from Etawa crossbreed goat’s milk

2019 ◽  
Vol 1 (1) ◽  
pp. 23-25
Author(s):  
Khairan Khairan ◽  
◽  
Cut Yulvizar ◽  
Suri Raihan Safriani ◽  
◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
Biochemical Assay ◽  
Dairy Goats ◽  
Morphological Examination ◽  
Isolation And Characterization ◽  
Goat’S Milk ◽  
Goat's Milk

Goat’s milk is white liquid derived from ruminant types of dairy goats. Milk is one of habitats of lactic acid bacteria (LAB). LAB have a potential as antimicrobial because capable to kill the pathogenic bacteria. LAB isolated from Etawa crossbreed goat’s milk were characterized to stipulate the genus of the isolates. Characterization of LAB consists of colony, morphology and biochemical assay. The morphological examination of the colony, cell morphology and biochemical assay showed that three isolates were identified as Leuconostoc, Enterococcus and Lactobacillus. The antimicrobial activity assay showed that those isolates exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli, but those isolates did not exhibit antifungal activity against Candida albicans.

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