Characterisation of lactic acid bacteria diversity in the Maltese sheep cheese

Probiotic bacteria can confer health benefits to the human gastrointestinal tract. Lactic acid bacteria (LAB) are candidate probiotic bacteria that are widely distributed in nature and can be used in the food industry. The objective of this study is to isolate and characterize LAB present in raw and fermented milk in Saudi Arabia. Ninety-three suspected LAB were isolated from thirteen different types of raw and fermented milk from indigenous animals in Saudi Arabia. The identification of forty-six selected LAB strains and their genetic relatedness was performed based on 16S rDNA gene sequence comparisons. None of the strains exhibited resistance to clinically relevant antibiotics or had any undesirable hemolytic activity, but they differed in their other probiotic characteristics, that is, tolerance to acidic pH, resistance to bile, and antibacterial activity. In conclusion, the isolates Lactobacillus casei MSJ1, Lactobacillus casei Dwan5, Lactobacillus plantarum EyLan2, and Enterococcus faecium Gail-BawZir8 are most likely the best with probiotic potentials. We speculate that studying the synergistic effects of bacterial combinations might result in a more effective probiotic potential. We suspect that raw and fermented milk products from animals in Saudi Arabia, especially Laban made from camel milk, are rich in LAB and have promising probiotic potential.

Background and Aim: Lactic acid bacteria (LAB) became a field of interest by scientists in recent years due to their technological and probiotic properties. The aim of this work was to study the technological and probiotic properties of LAB isolated from the bottle gourds (calabashes)of milk fermentation, in Mbéré, Cameroun.
 Methods: Five different bottle gourds from milk fermentation were collected and used for LAB isolation. These LABs were characterized using conventional cultural method, the technological (such as proteolytic, lipolytic activities) and probiotic properties (including acid and bile salt tolerance, cholesterol assimilation and antioxidant activities) were assessed.
 Results: From these samples, 30 LABs were isolated and among them, 21 exhibited great lipolytic and proteolytic activities with the maximum values of 18 and 29 mm respectively. In addition, 10 LAB isolates showed interesting antimicrobial activity against pathogens germs tested and good tolerance ability under acid and bile salt stress after 24h of incubation. Cholesterol assimilation and antioxidant tests revealed that isolated BC4 and BC3 have the greatest activity (35 and 39 mm respectively) while, BC4 and BL4 have the greatest antioxidant activity (IC50 = 0,15 and 0,13 respectively).
 Conclusion: LAB isolated from the bottle gourds (calabashes) of milk fermentation, in Mbéré, Cameroon can be used to develop dairy industry and manage the cardiovascular diseases.

This study aimed to isolate lactic acid bacteria from sheep milk products and to characterize these microorganisms with a focus on their antimicrobial, proteolytic and lipolytic activities. Raw milk, pasteurized milk, pasteurized cream, and butter samples were collected, lactic acid bacteria were isolated and their proteolytic, lipolytic and antimicrobial activities were evaluated. Lactic acid bacteria counts were higher in raw milk collected at the farm number 4 (8.91 ± 0.05 log CFU/mL), in which adequate hygienic practices were observed for pre- and post-milking. A total of 253 isolates were obtained, and among them 37 were lactic acid bacteria, where 19 showed some type of activity, most of which from raw milk. Among the isolates of lactic acid bacteria, 48.65% (n=18) showed proteolytic activity, 13.51% (n=5) lipolytic activity, 10.81% (n=4) showed both proteolytic and lipolytic activities, and only 2.70% (n=1) showed antimicrobial activity. Isolation of lactic acid bacteria with technological properties demonstrated their potential use as starter cultures in processing of fermented dairy products.

Antilisterial activity of raw sheep milk from two native Epirus breeds: Culture-dependent identification, bacteriocin gene detection and primary safety evaluation of the antagonistic LAB biota

Lactic acid bacteria (LAB) are valuable for the production of fermented dairy products. We investigated the functional traits of LAB isolated from artisanal cheeses and raw sheep milk, assessed their safety status, and explored the genetic processes underlying the fermentation of carbohydrates. Lactiplantibacillus plantarum had the largest and more functional genome compared to all other LAB, while most of its protein-encoding genes had unknown functions. A key finding of our analysis was the overall absence of acquired resistance genes (RGs), virulence genes (VGs), and prophages, denoting that all LAB isolates fulfill safety criteria and can be used as starter or adjunct cultures. In this regard, the identified mobile genetic elements found in LAB, rather than enabling the integration of RGs or VGs, they likely facilitate the uptake of genes involved in beneficial functions and in the adaptation of LAB in dairy matrices. Another important finding of our study was that bacteriocins and CAZymes were abundant in LAB though each species was associated with specific genes, which in turn had different activity spectrums and identified applications. Additionally, all isolates were able to metabolize glucose, lactose, maltose, and sucrose, but Lactiplantibacillus plantarum was strongly associated with the fermentation of rhamnose, mannose, cellobiose, and trehalose whereas Levilactobacillus brevis with the utilization of arabinose and xylose. Altogether these results suggest that to fully exploit the beneficial properties of LAB, a combination of strains as food additives may be necessary. Interestingly, biological processes involved in the metabolism of carbohydrates that are not of direct interest for the dairy industry may yield valuable metabolites or activate pathways associated with beneficial health effects. Our results provide useful information for the development of new probiotic artisanal cheeses and probiotic starter cultures.

Probiotic bacteria, primarily lactic acid bacteria (LAB), are known to improve gut health, enhance immune responses, and inhibit the growth of pathogenic microorganisms, making them valuable for functional foods. Naturally fermented sorghum is a rich source of these beneficial bacteria. Therefore, this study investigated the probiotic potentials of LAB isolated from the supernatant of fermenting sorghum (omidun). Five omidun samples were fermented for 12, 24, 48, 72, and 96 hours to recover LAB strains. The recovered LAB isolates were identified and characterized using morphological and molecular methods, while their antibiotic resistance profiles were also assessed. Furthermore, we examined the effects of different fermentation periods (12, 24, 48, 72, and 96 hours) on the probiotic potential of the isolated LAB, including temperature tolerance, acid resistance (pH), and bile salt tolerance. Our results showed that bacterial counts in omidun ranged from 2.78 × 10⁻³ − 4.1 × 10⁻³ CFU/ml, while coliform counts varied from 0.00–1 × 10⁻⁴ CFU/ml. The dominant LAB strains recovered from the omidun include Lactobacillus plantarum, Lactobacillus sp., Limosilactobacillus fermentum, and Lactobacillus brevis. Interestingly, biochemical tests confirmed all isolates were oxidase- and catalase-negative, with cocci and bacillary morphologies. Antibiotic resistance tests revealed that LAB fermented for 72 and 96 hours were resistant to gentamicin, ceftazidime, cloxacillin, erythromycin, cefuroxime, ofloxacin, augmentin, and ceftriaxone. Notably, the LAB isolates exhibited different growth patterns at 25, 37, and 40°C over 1- and 3-hour intervals, with all isolates successfully growing at 40°C. All isolates maintained high viability after 3 hours at both pH 2.5 and 4.0, while those fermented for 12–48 hours showed no growth in both bile levels. The findings from this study suggest that omidun is a rich source of LABs, with fermentation duration, especially 72 hours, playing a crucial role in shaping their probiotic potential.

Lactic acid bacteria (LAB) isolates possessed functional probiotic attributes, such as high hydrophobicity and autoaggregation ability, coaggregation capability with bacterial pathogens, antimicrobial activity, antioxidant potential, and hypocholesterolemic effects. Selected potential probiotic LAB, i.e. Lactobacillus paracasei M3, L. casei M5, L. paracasei M7, and few others were studied for their ability to lower cholesterol using a number of methods viz. cholesterol assimilation, bile salt deconjugation, cholesterol co-precipitation, cholesterol adhesion to probiotic cell wall, and miceller sequestration of cholesterol. L. casei M5 showed maximum bile salt hydrolase (BSH) activity, and released 57.63nmol of glycine/min, and was closely followed by LAB isolate M9 which generated 52.12nmol of glycine/min. Sodium glycocholate was deconjugated by L. casei M5 to produce 27.77μmol/mL of cholic acid, while other isolates produced 20-26μmol/mL of cholic acid. Cholesterol was assimilated significantly by isolate M6 (82.15%) and L. casei M5 (76.51%). L. casei M5 showed higher cholesterol co-precipitation ability (50.16μg/mL) as compared to other LAB isolates (33-44μg/mL). Miceller cholesterol concentration was reduced maximally byLAB isolate M8 (87.5%), followed by isolates M5 (84.75%), M9 (84%), M10 (80%), and M37 (79%). Higher cell wall adhesion of cholesterol was realized by L. casei M5 (42.48μg/mL) than other LAB isolates (30-40μg/mL). Selected LAB probiotics demonstrated short chain fatty acid (acetate, propionate, and butyrate) producing ability, yet another way of probiotics-mediated cholesterol lowering.

There are massive bacteria in the raw milk, especially the lactic acid bacteria (LABs), which have been considered probiotics in humans and animals for a long time. Novel probiotics are still urgently needed because of the rapid development of the probiotic industry. To obtain new LABs with high probiotic potential, we obtained 26 LAB isolates, named L1 ~ L26, from local Holstein raw milk collected from a farm whose milk had never been used for LAB isolation. We identified them at the species level by biochemical and 16S rDNA sequencing methods. Their antagonistic activities against four target pathogens (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa PAO1, and Salmonella enterica H9812), co-aggregative ability with these target pathogens, survivability in the simulated gastrointestinal tract conditions and phenol, auto-aggregation and hydrophobicity, hemolytic activity, and antibiotic susceptibility, were evaluated in vitro. Five Lactiplantibacillus plantarum isolates (L5, L14, L17, L19, and L20) showed more promising probiotic potential than others. Specifically, these five isolates conglutinated with and inhibited all the target pathogens, and survived in the simulated gastric juice (92.55 ~ 99.69%), intestinal juice (76.18 ~ 83.39%), and 0.4% phenol (76.95 ~ 88.91%); possessed considerable auto-aggregation (83.91 ~ 90.33% at 24 h) and hydrophobicity (79.32 ~ 92.70%); and were non-hemolytic, sensitive to kinds of common antimicrobials. Our findings demonstrated that these five isolates could be preliminarily determined as probiotic candidates because they have better probiotic potential than those previously reported. Again, this study highlighted the potential of raw milk for probiotic isolating and screening and provided the probiotic industry with five new LAB candidates.

Background: There has been an increase in public health concern over post-harvest spoilage fungi in plantain. This study aimed to explore the role of Lactic Acid Bacteria (LAB) from fermented foods against spoilage fungi of plantain. Methods: Seventy-five LAB were isolated from agadagidi and ogi between February and April 2021. Cell-Free Supernatants (CFS) of the broth cultures were obtained by centrifugation. Spoilage fungi were obtained from plantain with visible mould growth. Initial screening of the LAB isolates for antifungal activities was carried out using the agar overlay method. The agar well diffusion method was used to assay the inhibitory spectrum of the CFS. Data obtained for the inhibition diameters were analysed using descriptive statistics (IBM SPSS 22). LAB isolates with the highest antifungal activity were assessed for their safety via the DNase, gelatinase, and haemolysis tests, and were identified by 16S rRNA sequencing. Results: Twenty-six LAB isolates exhibiting antifungal activity were obtained from the samples. The isolated spoilage fungi included Aspergillus flavus, Fusarium oxysporum, Fusarium verticilliodes, Penicillium sp, and Rhizopus sp. Nine of the 26 LAB isolates produced inhibition zones >14 mm in diameter. The CFS of isolate 5AG8 had antifungal activity against the spores of A. flavus, F. oxysporum, and Penicillium sp. The CFS of isolate AG1 inhibited the mycelial growth of F. verticilliodes and Penicillium sp, while the CFS of isolate OP was active against the spores of A. flavus and Penicillium sp. None of the isolates tested positive in the safety assessment tests. The isolates were identified as Lactobacillus plantarum OP, L. plantarum AG1, and Lactobacillus fermentum 5AG8. Conclusion: This study revealed that LAB strains from agadagidi and ogi are safe for use in food matrices and their metabolites can be used in the control of spoilage fungi in plantain.

The aim of this study was to isolate and characterize lactic acid bacteria (LAB) from spontaneous fermentation of jalapeno pepper. Three strains of LAB were isolated from the spontaneous fermentation of peppers: Lactobacillus brevis P.16564, Lactobacillus brevis P.36564, and Lactobacillus rossiae P.26562, which were identified by amplification of the 16S rRNA gene. All strains showed marked viability after exposure to simulated gastric and pancreatic juice. Strain P.36564 showed greater viability when exposed to sequential stress from gastric and pancreatic juice. All strains showed antimicrobial activity on Escherichia coli (ATCC 25922) and Salmonella sp. (ATCC 700623). As for safety aspects, all strains are considered safe for human consumption. All strains have a high percentage of hydrophobicity and autoaggregation. The percentage of coaggregation of LAB with E. coli was low. These results suggest that LAB isolated from pepper may have a probiotic potential. Practical applications The spontaneous fermented pepper is an excellent source of lactic acid bacteria (LAB). In this study, it was possible to obtain strains of LAB with excellent probiotic potential and antimicrobial activity against Salmonella sp. (ATCC 700623) and E. coli (ATCC 25922). The isolated strains of peppers could be used in the preparation of different fermented foods. The results of this research demonstrate the potential of the strains for future use by the fermented food industry.

This study explores the probiotic potential of lactic acid bacteria (LAB) in horse milk from Tambora, West Nusa Tenggara by examining its functional and probiotic attributes, including bile salt tolerance, low pH, simulated gastric juice (SGJ), simulated intestinal juice (SIJ), antibacterial activity, as well as bile salt hydrolase (BSH) genes. Genotyping of LAB was performed using restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) analysis and then identified based on the 16S rRNA gene. A total of 25 LAB isolates showed the ability to grow at low pH, tolerant to bile, and survived under SIJ and SGJ conditions. The BSH gene was confirmed in three isolates, namely: SK1-28, SK2-30, and SK2-34. Results of RFLP-PCR analysis showed that the LAB isolates were grouped into three groups based on the number and molecular weight of the differences DNA fragments. The 16S rRNA analysis showed that the first two groups were Lacticaseibacillus rhamnosus, whereas the third group was Lactiplantibacillus plantarum. In addition, all Lacticaseibacillus rhamnosusisolates in group I showed the ability to grow at pH 9.0, but not group II. It can be concluded that Lacticaseibacillus rhamnosus and Lactiplantibacillus plantarum can be used as the indigenous probiotic bacteria source from Indonesia.

Probiotics are live microorganisms acclaimed to provide health benefits when consumed and are generally considered safe for consumption. The lactic acid bacteria (LAB) are common groups of bacteria with certain health benefits, including the ability of some strains to play probiotic roles. Some indigenous fermented foods localized in Ado-Ekiti carry LAB that may have some probiotic properties. The aim of this study was to determine the probiotic potential of some LAB isolated from some local fermented foods in Ado- Ekiti. Samples of locally fermented foods: “garri”, “iru”, “ogi”, and “fura de nono” were obtained from the local market in Ado-Ekiti for isolation of LAB. All samples were cultured using standard methods. A total of sixteen (16) isolates were recovered from the samples and screened for their antibacterial activity against four human pathogenic bacterial strains which were Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Staphylococcus aureus. The LAB with enhanced antibacterial activity were further screened for potential probiotic characteristics using pH tolerance test, bile salt tolerance test, NaCl tolerance test, temperature sensitivity, and lactose utilization. The LAB isolates identified from the local food samples included: Lactobacillus fermentum, Acetobacter spp., Bacillus subtilis, Lactobacillus plantarum, and Lactococcus lactis. Out of the 16 strains obtained, five strains that showed considerable antibacterial activity were evaluated for their probiotic potential. The five strains were susceptible to conventional antibiotics. It was also shown that the five strains were able to grow at the selected range of pH 4.0 – 7.0, they were able to survive at the temperature ranges between 20 oC and 45 oC, they were lactose-tolerant, and they were able to tolerate 1 – 5% sodium chloride (NaCl) concentration. Some isolated LAB exhibited excellent probiotic characteristics and thus can be recommended as a potential use as probiotics. The findings of this study suggest that popular local foods in Ado Ekiti, such as “garri”, “iru”, “ogi”, and “fura de nono”, harbor some LAB with potential probiotic properties, and can be explored for possible health benefits.

Korean kimchi-derived lactic acid bacteria inhibit foodborne pathogenic biofilm growth on seafood and food processing surface materials

Raw milk is usually contaminated with pathogenic bacteria. Fermentation of milk is important to inhibit the growth of contaminants, spoilage, and pathogenic bacteria. The objective of this study was to isolate lactic acid bacteria from fermented milk and evaluate their antimicrobial activity against selected pathogenic bacteria. Laboratory-based experimental study design was conducted from May-July, 2021.Three samples of Ergo (each of 250 ml) were collected from Jimma town. Lactic acid bacteria (LAB) isolates were identified through integrated phenotypic techniques. Further identification was conducted through using API 50 CHL strips. Antimicrobial activities (AMAs) of LAB isolates were tested against clinical isolates of E. coli, S. aureus, and Salmonella spp. using agar well diffusion method. The data were analyzed by using SPSS software version 21 and Microsoft Excel spreadsheet. Tables and figures were applied to describe characteristics of data. Twelve LAB isolates were identified. Those LAB isolates include six Lactococcus lactis subsp. lactis, Lactobacillus acidophilus (2), Lactiplantibacillus plantarum (1), Limosilactobacillus fermentum (2), and Leuconostoc lactis (1). Based on primary screening of LAB, isolates/strains ESCIa, ESBIa, and ESCIc show strong AMA against S. aureus, E. coli, and Salmonella spp. The CFS of ESCIc showed the highest AMA against S. aureus and Salmonella spp. with a zone of inhibition of 14.12 ± 1.6 mm and 12.9 ± 3.6 mm, respectively, while ESBIa showed the highest AMA against E. coli with a zone of inhibition of 13.5 ± 2.1 mm. The CFSs of selected LAB strains were heat tolerant at varying temperatures up to 100°C. The CFSs of selected LAB strains were inactivated by proteinase enzymes, but they are not inactivated with amylase enzymes. Conclusions and Recommendation. All 12 LAB isolates exhibited antimicrobial activity against tested bacterial strains. Lactobacillus isolates showed the highest antagonistic activity on tested indicator strains. Thus, they are possible alternatives to antibiotics in the era of antimicrobial resistance. S. aureus was the most sensitive to antimicrobial effects/agents of selected LAB isolates. Consumption of fermented foods is advisable since they support the growth of healthy GIT microbiota. Fermentation serves as biopreservation of food. However, analysis of probiotic features and in vivo probiotic effects of those LAB isolates will be subject of future research/study.

In Ethiopia, poultry production is vital for enhancing the local economy, promoting food security, and alleviating poverty. However, the sector has faced significant challenges due to diseases and antibiotic resistance. This study aimed to isolate, evaluate, and characterize the probiotic potential of lactic acid bacteria (LAB) from the gut of chickens for their application as effective probiotics in poultry. Free-range indigenous chickens were sourced from local households in Bishoftu Town and its surroundings, while broiler chickens were from a commercial hatchery in the same area. The probiotic potential of the LAB isolates was assessed using standard protocols, with identification performed using Matrix-assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS). A total of 149 LAB were isolated and characterized. Nineteen of these isolates exhibited a broad zone of inhibition against all test bacteria, with the most significant inhibition observed against L. monocytogenes (21.33 ± 1.58 mm) and the least against S. Typhimurium (10.00 ± 1.00 mm). The survival percentages of six LAB isolates at pH levels of 2, 2.5, and 4 exceeded 82%, with survival rates above 84% observed at a 0.3% bile salt concentration. Additionally, adherence to the chicken gut ranged between 54% and 55% for the six LAB isolates tested. Notably, none of the isolates exhibited hemolytic activity. All heat-treated cell-free supernatants demonstrated antimicrobial activity against the test pathogens. However, the supernatants treated with pronase (isolates B12CA and B1I8) and those adjusted to pH 7 exhibited no antimicrobial activity. The MALDI-TOF MS presumptively identified the six LAB isolates as Lactobacillus reuteri DSM 20016T and Pediococcus pentosaceus DSM 20206. These lactic acid bacteria demonstrated potential probiotic attributes, making them effective supplements for managing enteric pathogens and improving chicken performance. Further analysis, including in vivo studies and molecular safety assessments, is necessary to evaluate the potential probiotics identified from the gut of free-range indigenous and broiler chickens for future applications.