Characterization and antimicrobial activities of lactic acid bacteria isolated from selected Nigerian traditional fermented foods (original) (raw)
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Antimicrobial Activity of Lactic Acid Bacteria Isolated from Traditional Fermented Food
Tribhuvan University Journal of Microbiology, 2021
Objective: The main objective is to isolate Lactic acid bacteria from traditional fermented food of Kathmandu valley and to study their antimicrobial properties by agar well diffusion method. Methods: A total of 30 samples of 4 different types of traditional fermented food (Gundruk and sinki, Pickles and Dahi) were obtained from Kathmandu valley and processed in Microbiology Laboratory of Padma Kanya Multiple Campus. For identification of Lactic acid bacteria (LAB), Gram staining, catalase and motile tests were done. In the carbohydrate fermentation test, all isolates were processed for fermentation of glucose, lactose, sucrose and fructose. Bacteriocin was extracted by precipitation method. Antibiotic susceptibility of the isolates was determined by using modified Kirby-Bauer disc diffusion method. The antimicrobial activity of Lactic acid bacterial (LAB) was done by agar well diffusion method. Results: A total of 21 LAB isolates were identified which were 10 Lactobacillus spp (47.6%), 8 Pediococcus spp (38.0%) and 3 Streptococcus spp (14.3%). The antimicrobial activity of bacteriocin showed inhibitory activity against Shigella spp, Escherichia coli and Bacillus spp but didnot show inhibition to Staphylococcus aureus, Salmonella spp. and Klebsiella pneumoniae. For the quality control, the antimicrobial activity of bacteriocin was done on ATCC (25923) Staphylococcus aureus. All isolates were susceptible to ampicillin while resistant to nalidixic acid and Co-trimoxazole. Conclusion: The present study showed the bacteriocin produced by LAB from traditional fermented food (Gundruk and Sinki, yogurt and Pickle) showed antimicrobial activity against different bacteria which underline its important role in improving food quality and increasing safety.
Journal of Advances in Microbiology , 2022
This study identified the antimicrobial compounds found in lactic acid bacteria isolated from several traditional fermented foods, such as ogi, ugba, and yoghurt, as well as their antimicrobial effectiveness against a few chosen food pathogens. Fifteen (15) food samples including five each for yoghurt, ogi, and ugba were tested for the presence of lactic acid bacteria. Nine organisms were isolated from the food samples and were phenotypically and genotypically characterized. It was discovered that two of the isolates were Lactococcus spp, five Lactobacillus spp, one Bacillus spp, and one Streptococcus spp. The genotypic characterization revealed that the lactic acid bacteria isolates Lactococcus lactis subsp. lactis 0711XYBLS, Lactobacillus fermentum CS19, Lactococcus lactis and Lactobacillus fermentum were closely related at 99% evolutionary distance. For the sole purpose of this research, Lactococcus lactis subsp. lactis 0711XYBLS and Lactobacillus fermentum CS19 were utilized to determine their antimicrobial potentials against selected food pathogens.
Food Science and Biotechnology, 2011
The isolation and screening of lactic acid bacteria (LAB) from natural sources have been one of the powerful means to obtain strains for the food industry. A total of 275 indigenous isolates were obtained from 43 samples of traditional fermented foods in specific ecological niches throughout the northwestern China, and among which 13 strains of LAB were selected for their potential in food preservation and production. Among the 13 isolates, Lactobacillus (10) was dominant over Lactococcus (3). The distribution of the isolates was as follows: Lactobacillus paracasei ssp. paracasei (J23, M10, M20, M22), Lactobacillus rhamnosus (J20, M18), Lactococcus lactis ssp. lactis (X20, Q7), Lactobacillus casei (Q1, Q12), Lactobacillus plantarum (J11), Lactococcus lactis ssp. cremoris (X8), Lactobacillus delbrueckii ssp. bulgaricus (Q5). All 13 isolates produced bacteriocin with a broad inhibitory spectrum against selected Gram-positive as well as Gram-negative pathogenic and spoilage species. Biochemical analysis revealed that they possessed high acidification and coagulation activity. Several strains possessed the high activity of 2 or 3 technological characteristics, related to novel starters and food preservatives.
Journal of Natural Sciences Research, 2014
Lactic acid bacteria (LAB) are a group of Gram-positive, non-spore forming, cocci or rods, which produce lactic acid as the major end product during the fermentation of carbohydrates. The genera Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Streptococcus are important members of this group. The taxonomy of lactic acid bacteria has been based on the Gram reaction and the production of lactic acid from various fermentable carbohydrates.The classification of lactic acid bacteria into different genera is largely based on morphology, mode of glucose fermentation, growth at different temperatures, and configuration of the lactic acid produced, ability to grow at high salt concentrations, and acid or alkaline tolerance. Based on sugar fermentation patterns, LAB are classified into homofermenters and heterofermenters. Lactic acid bacteria have been used in the treatment of infections and in the production of foods, especially fermented foods (such as yoghurt, Cheese, etc.) because they can produce several compounds that contribute to taste, smell, color, and texture of the foods. In addition, they can produce antimicrobial substances including bacteriocins. LAB have the ability to inhibit pathogenic and food spoilage bacteria. The bacteriocins synthesized by different lactic acid bacteria inhibited the growth of the test organisms used and this was observed through the production of zones of inhibition on the plates.
Seven species of Lactic Acid Bacteria (LAB) namely L. fermentum, L. casei, L. brevis, L delbrueckii, L. acidophilus, L. plantarum and Leuconostoc mesenteroides were isolated from ogi, burukutu and retted cassava (fufu). The isolates were screened for quantitative production of lactic acid using normal MRS broth and modified MRS broth under varying conditions of growth such as temperature and pH and influence of carbon and nitrogen sources. It was observed that all the test isolates best utilized glucose and yeast extract at concentrations of 20 g LG and 5 g LG respectively for production of lactic acid at optimum temperature of 1 1 30°C and pH of 5.5. L. plantarum produced the highest quantity (2.95±0.32 g LG ) of lactic acid while L.
International Journal of Microbiology, 2021
Background. Lactic acid bacteria from fermented foods and fish can antagonistically inhibit the growth of foodborne pathogenic organism in fermented food and they stimulate the immune response to protect the fish from certain kinds of infections. e aim of this study was to evaluate the in vitro antagonistic activities of lactic acid bacteria isolated from fermented beverage (Borde) and finfish on foodborne pathogenic microorganisms. Methods. Laboratory-based experimental study was conducted from May 1 to Sep 1, 2020. Total sample numbers were 60 samples of fermented beverage (Borde) and 20 of finfish which were collected from different households and Chamo Lake (Arba Minch, Ethiopia). Each sample was firstly homogenized and serial dilution was prepared and spread on MRS agar plates in order to isolate pure culture. Different biochemical tests were performed to identify isolated bacteria. en, cell-free supernatant (CFS) was prepared from MRS culture and used in an antimicrobial assay that was performed by agar diffusion method. e effects of pH, temperature, and enzymes on antimicrobial activity were evaluated in the same test. Simultaneously, the effects of lactic acid bacteria on aflatoxin production and on the permeability of the membrane were also evaluated. Data were analyzed using one-way ANOVA and Tukey post hoc analysis was performed by SPSS 25 statistical software. Result. A total of 40 lactic acid bacteria were isolated; among them, 4 lactic acid bacteria, belonging to the genera Enterococcus, Leuconostoc, and Weisellia from fermented beverage and Pediococcus from fish, were screened for antimicrobial activity. e cell-free supernatant of those four isolates exhibited a significant (p < 0.05) antibacterial effect against tested pathogens and foodborne pathogenic bacteria. In addition, CFS showed antifungal and antiaflatoxigenic activities. e antimicrobial compounds synthesized by these isolates were sensitive to some proteolytic enzymes, and they were proved to be stable at high temperatures. It maintained/retained antimicrobial activity in a wide range of pH 2.0-10. Enterococcal CFS exhibited antibacterial activity against S. aureus on membrane permeability, as confirmed by the increase in absorbance value between 0.075 and 0.24 at OD 280-nm and between 0.68 and 1.2 at OD 260-nm. Conclusion. Cell-free supernatant produced by isolated lactic acid bacteria showed antimicrobial activity against a wide range of Gram-positive and Gram-negative foodborne bacteria, suggesting its potential application as a natural antimicrobial agent in tackling the rising drug resistance against foodborne pathogens.
Journal of Physics: Conference Series, 2019
This study aims to obtain lactic acid bacteria (LAB) which have probiotic properties and inhibitory effects against pathogens. Peda fish fermented in 20% salt solution used as samples. Antimicrobial properties of LAB isolates against gram-positive and gram-negative pathogens (Salmonella typhi BPE 127.1.MC, Salmonella typhi BPE 122.4.CCA, Salmonella typhi NCTC 786, Salmonella typhimurium FNCC 0050, Pseudomonas putida FNCC 0071, Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923) were tested using agar well diffusion method. To exclude acid production, the cell-free culture supernatant (CFCS) solution was neutralized using 1 N NaOH before antimicrobial activity was tested. Likewise with bacteriocin tests, CFCS solutions that have been neutralized, were treated first by heating at 100ºC for 10 minutes in order to enzyme inactivation. A total of 26 out of 50 LAB isolates showed clear zones in the MRS-CaCO3 agar medium, gram positive, and negative catalase as the main chara...
Lactic acid bacteria from freshly prepare 'Ogi' and 'Kunun' were isolated by plating on nutrient agar modified with glacial acetic acid. The identification of the isolates was carried out using biochemical methods. The identified isolates (Lactobacillus planetarium, Lactobacillus sake, Lactobacillus acidophilus fermentum) were screened for their ability to produce bacterocin against food borne pathogens (Escherichia coli and Staphylococcus aures) using the pour plate method. The isolated organisms inhibited different food borne pathogens with different zones of inhibition. The highest was exhibited by Lactobacillus fermentum on Escherichia coli (38mm) while the least was by Lactobacillus acidophilus on Staphylococcus aures (18mm). Fresh Ogi constituted a better source of lactic acid bacteria than that of Kunun. The antimicrobial activity of the four LAB strains was inactivated by the addition of proteinase K, thus confirming the proteinaceous nature of the inhibition. The bacterocin of lactic acid bacteria have potential application for assessing and improving food quality, and safety
This study aims to screen the antibacterial activity of lactic acid bacteria (LAB) isolated from home-made fermented vegetables against common food borne pathogens. The antagonistic properties of these isolates against Escherichia coli, Staphylococcus aureus, Yersinia enterocolitica and Bacillus cereus were examined using agar well diffusion method. Four LAB namely MF6, MF10, MF13, and MF15 identified as Lactobacillus animalis, Lactobacillus rhamnosus, Lactobacillus fermentum and Lactobacillus reuteri, respectively were effective against all selected pathogenic strains. Amongst the four isolates, MF6 exhibited the highest antibacterial activity, against all the indicator pathogens tested except Y. enterocolitic. Its activity was maximum against E.coli with a Zone of Inhibition (ZOI) ranging from 18.7 to 21.3 mm and least for Y. enterocolitica (10±1.1 mm). Isolate MF13 also showed antimicrobial property against all tested pathogens showing highest activity against Y. enterocolitica (14 ± 1.7 mm) and least against E.coli (8 ± 1.4 mm), which was in direct contrast to isolate MF6. Isolate MF15 showed greater activity against E.coli (12 ± 0.8 mm) and least against S. aureus (8 ± 1.7 mm). Least antimicrobial property was observed in isolate MF10, with a ZOI in the range of 2.5-7 mm. The degree of antimicrobial property among the isolates was in the order of MF6>MF13>MF15>MF10. Overall, the isolated LAB showed the remarkable inhibitory effect against both Gram positive and Gram negative pathogenic strains. However, the spectrum of inhibition was different for the isolates tested. These results suggest that this potent isolates could be used as a natural biopreservatives in different food products.
Bioresource Technology, 2007
Two traditional fermented food ‘tapai’ (fermented tapioca) and ‘tempoyak’ (fermented durian flesh), chilli puree and fresh goat’s milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from ‘tapai’, produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat’s milk.