Foodborne Pathogenic Bacteria Research Articles

The ArgR-Regulated ADI Pathway Facilitates the Survival of Vibrio fluvialis under Acidic Conditions

Vibrio fluvialis is an emerging foodborne pathogenic bacterium that can cause severe cholera-like diarrhea and various extraintestinal infections, posing challenges to public health and food safety worldwide. The arginine deiminase (ADI) pathway plays an important role in bacterial environmental adaptation and pathogenicity. However, the biological functions and regulatory mechanisms of the pathway in V. fluvialis remain unclear. In this study, we demonstrate that L-arginine upregulates the expression of the ADI gene cluster and promotes the growth of V. fluvialis. The ADI gene cluster, which we proved to be comprised of two operons, arcD and arcACB, significantly enhances the survival of V. fluvialis in acidic environments both in vitro (in culture medium and in macrophage) and in vivo (in mice). The mRNA level and reporter gene fusion analyses revealed that ArgR, a transcriptional factor, is necessary for the activation of both arcD and arcACB transcriptions. Bioinformatic analysis predicted the existence of multiple potential ArgR binding sites at the arcD and arcACB promoter regions that were further confirmed by electrophoretic mobility shift assay, DNase I footprinting, or point mutation analyses. Together, our study provides insights into the important role of the ArgR-ADI pathway in the survival of V. fluvialis under acidic conditions and the detailed molecular mechanism. These findings will deepen our understanding of how environmental changes and gene expression interact to facilitate bacterial adaptations and virulence.

Biosynthesis of alternan-stabilized selenium nanoparticles: A study on characterization and applications for antibacterial and antifungal purposes

In this study, the alternan/selenium nanoparticles (Alt/SeNPs) were characterized with respect to their formation, morphology, size, selenium distribution, molecular, crystallographic, and thermal properties using UV–Vis spectroscopy, SEM, TEM, EDAX, FTIR, XRD, DSC and TGA measurements. UV–VIS measurements confirmed the synthesis of nanoparticles by observing a maximum surface plasmon resonance peak at 212 nm. In this study, alternan contributed to stabilizing the dispersion of SeNPs, resulting in a cluster of spherical and well-dispersed nanoparticles ranging in size from 50 to 90 nanometers. Nanoparticles were found to be highly thermally stable and in a nanocrystalline structure. The ABTS and CUPRAC radical scavenging activities of Alt/SeNPs were remarkable (95% and 78% at 4 and 6 mg/mL levels of Alt/SeNPs, respectively). Alt/SeNPs had also good inhibitory activities (3.5–4.0 and 4–15 mm of inhibition zone levels at 5 mg/mL level of Alt/against foodborne pathogenic bacteria and fungi, respectively).

Isolation and Biological Characteristics of a Novel Phage and Its Application to Control Vibrio Parahaemolyticus in Shellfish Meat.

Vibrio parahaemolyticus is a common foodborne pathogenic bacterium. With the overuse of antibiotics, an increasing proportion of drug-resistant strains are emerging, which puts enormous pressure on public health. In this study, a V. parahaemolyticus-specific phage, VP41s3, was isolated. The head length, width, and tail length of the phage were 77.7 nm, 72.2 nm, and 17.5 nm, respectively. It remained active in the temperature range of 30-50°C and pH range of 4-11. The lytic curve of phage VP41s3 showed that the host bacteria did not grow until 11 h under phage treatment at MOI of 1000, indicating that the phage had good bacteriostatic ability. When it was added to shellfish contaminated with V. parahaemolyticus (15°C, 48 h), the number of bacteria in the experimental group was 2.11 log10 CFU/mL lower than that in the control group at 24 h. Furthermore, genomic characterization and phylogenetic analysis indicated that phage VP41s3 was a new member of the Podoviridae family. The genome contained 50 open reading frames (ORFs), in which the ORF19 (thymidine kinase) was an enzyme involved in the pyrimidine salvage pathway, which might lead to the accelerated DNA synthesis efficiency after phage entered into host cells. This study not only contributed to the improvement of phage database and the development of beneficial phage resources but also revealed the potential application of phage VP41s3 in food hygiene and safety.

Fabrication of cellulose-based antimicrobial films integrated with in situ synthesized silver nanoparticles using Psidium guajava leaf extract

Cellulose-based antibacterial nanocomposite films were prepared by adding silver nanoparticles (AgNPs) synthesized in situ using a guava leaf extract. The nanocomposite films were synthesized using the solution casting method and characterized by analytical methods. The FTIR analysis indicated the presence of the carbonyl groups of guava leaf extract and hydroxyl groups of cellulose in the in situ synthesized AgNPs. The XRD analysis confirmed the AgNPs in the nanocomposites. SEM analysis revealed the presence of spherical AgNPs in the size range of 60-90 nm. The addition of AgNPs increased the tensile strength and thermal stability of composites. In addition, the cellulose-based nanocomposite film wasn’t showed very significant antibacterial activity against various foodborne pathogenic bacteria. Therefore, the prepared cellulose/AgNPs nanocomposite film is eco-friendly and exhibits excellent tensile strength and thermal stability along with a wide range of antimicrobial activity, so it is considered to be suitable for biomedical and food packaging applications.

Identification of a dCache-type chemoreceptor in Campylobacter jejuni that specifically mediates chemotaxis towards methyl pyruvate.

The foodborne pathogenic bacterium Campylobacter jejuni utilizes chemotaxis to assist in the colonization of host niches. A key to revealing the relationship among chemotaxis and pathogenicity is the discovery of signaling molecules perceived by the chemoreceptors. The C. jejuni chemoreceptor Tlp11 is encoded by the highly infective C. jejuni strains. In the present study, we report that the dCache-type ligand-binding domain (LBD) of C. jejuni ATCC 33560 Tlp11 binds directly to novel ligands methyl pyruvate, toluene, and quinoline using the same pocket. Methyl pyruvate elicits a strong chemoattractant response, while toluene and quinoline function as the antagonists without triggering chemotaxis. The sensory LBD was used to control heterologous proteins by constructing chimeras, indicating that the signal induced by methyl pyruvate is transmitted across the membrane. In addition, bioinformatics and experiments revealed that the dCache domains with methyl pyruvate-binding sites and ability are widely distributed in the order Campylobacterales. This is the first report to identify the class of dCache chemoreceptors that bind to attractant methyl pyruvate and antagonists toluene and quinoline. Our research provides a foundation for understanding the chemotaxis and virulence of C. jejuni and lays a basis for the control of this foodborne pathogen.

Characterization and tolerance of foodborne pathogenic bacteria in microplastic biofilm

Microplastics have the ability to selectively accumulate microorganisms from their surrounding environments, leading to the formation of biofilms. The potential for microplastic biofilm in food processing environments to contaminate the processing environment and food matrices poses a threat to food safety. This study validated the biofilm formation of three commonly encountered foodborne pathogens, Salmonella enterica serovar Typhimurium (ST), Staphylococcus aureus (SA), and Listeria monocytogenes (LM) on microplastics, and investigated their tolerance to disinfectant and gastrointestinal tract. Three strains showed distinct biofilm formation patterns, with biomass reaching a steady state at 2 d. Meanwhile, the particle size of microplastics exhibited a specific impact on biofilm formation, with smaller microplastics sizes leading to increased biofilm formation. Sodium hypochlorite (NaClO) can effectively eliminate most biofilm-forming bacteria, except for ST. After treatment with 50 ppm NaClO, 34% cells in ST biofilm survived. Only SA survived in simulated gastric fluid, with around 3 log reduction after 1 h. ST and LM were not detected. All three strains showed a slight increase after treatment with simulated intestinal fluid for 6 h. These results highlighted the capacity of microplastics to transport pathogens through biofilms, emphasizing the potential synergistic effects between microplastics and pathogens in food-associated environments.

Purification, characterization, and identification of a novel bacteriocin produced by Lacticaseibacillus casei KLS1, and its antimicrobial mechanism against Staphylococcus aureus

Staphylococcus aureus (S. aureus) and its biofilm were recognized as one of the major threats to food safety and human health. Bacteriocins produced by Lacticaseibacillus species have been demonstrated to inhibit the growth of foodborne pathogenic bacteria and their biofilm formation. Herein, a novel bacteriocin KLS1 from Lacticaseibacillus casei KLS1 was extracted by ethyl acetate and purified using an AKTA Pure 25 protein chromatography purification system. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses revealed that the molecular mass of bacteriocin KLSI was 3786.91 Da and the amino acid sequence was DTSASIASNKSETNDLLKQIEAANTEVINLNKQID. Bacteriocin KLS1 was stable at pH 2.0∼6.0, sensitive to proteases, and showed excellent thermal stability. Furthermore, bacteriocin KLS1 exhibited broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria, even fungi. The crystal violet staining assay indicated that bacteriocin KLS1 significantly reduced the relative percentage of S. aureus biofilm (P < 0.05). Meanwhile, bacteriocin KLS1 was found to significantly decrease the metabolic activity of S. aureus by Cell Counting Kit-8 assay (P < 0.05). In addition, scanning electron microscopy and confocal laser scanning microscope showed that bacteriocin KLS1 disrupted the structure of S. aureus biofilm and cell membrane integrity, leading to cell deformation and leakage of contents. These results suggested that bacteriocin KLS1 might have the potential to serve as a biological preservative in the food industry.

Production of Polyclonal Antibodies and Development of Competitive ELISA for Quantification of the Lantibiotic Paenibacillin

The discovery and biotechnological application of new antimicrobial peptides are impeded by a lack of sensitive methods for peptide quantification. Paenibacillin is an emerging antimicrobial lantibiotic that was discovered in Paenibacillus polymyxa OSY-DF ATCC PTA-7852, isolated from the fermented vegetable Kimchee. This lantibiotic has potency against many foodborne pathogenic and spoilage bacteria. To advance the research and application of paenibacillin, a rapid, specific, and sensitive detection and quantification immunoassay was developed. After anti-paenibacillin polyclonal antibodies (pAbs) were generated and purified, a competitive enzyme-linked immunosorbent assay (cELISA) was developed and optimized for paenibacillin quantification. The dynamic range of the cELISA was determined by using a three-parameter nonlinear regression model, achieving a correlation (R2) value of 0.95. The cELISA displayed high sensitivity, with the ability to detect paenibacillin at levels as low as 15.6 ng/mL, which is significantly lower than the limit of detection of the conventional antimicrobial assay (20 µg/mL paenibacillin). The cELISA successfully differentiated paenibacillin concentrations in cell-free crude supernatants of P. polymyxa wild type and its mutant strain when grown at 30 °C and 37 °C; higher paenibacillin levels were found in the mutant (0.248–0.276 µg/mL) than in the wild type (0.122–0.212 µg/mL) culture. These findings were validated by the transcriptional analysis of 11 paenibacillin biosynthetic genes, which were significantly upregulated (≥2-fold increase) in the mutant compared with the wild strain. Additionally, the cELISA exhibited high sensitivity by recovery of paenibacillin titers spiked at 2.5 and 10 µg/mL in de Man, Rogosa, and Sharpe (MRS) broth and diluted skim milk. These results suggest that the anti-paenibacillin pAbs and the developed cELISA could be valuable in quantifying paenibacillin in complex matrices and in aiding the discovery of paenibacillin-producing natural microbiota.

Development and characterization of active packaging system based on zein nanofibers mat incorporated with geraniol‐loaded nanoliposomes

AbstractIn recent years, development of biopolymeric nanofibers as an active biodegradable packaging system has attracted specific attention. The objective of this research was to develop zein‐based electrospun nanofibers (NFs) incorporated with geraniol‐loaded nanoliposomes (G‐loaded NLPs). Geraniol was encapsulated into NLPs with an efficiency of 79.23%. The particle size and zeta potential of G‐loaded NLPs were 121.50 nm and −38.30 mV, respectively. The successful loading of geraniol in the NLPs was approved by Fourier transform infrared (FT‐IR) spectroscopy. The liposomal vesicles showed spherical shapes. G‐loaded NLPs were added in the zein‐based electrospun NFs at three different concentrations (0.25, 0.5, and 1%w/v). All NFs samples exhibited fibrillar structure. The increase of NLPs concentration enhanced the thermal stability of the NFs. However, the crystalline structure of zein NFs did not change by the addition of G‐loaded NLPs. The highest surface hydrophobicity was related to the NFs containing 1% G‐loaded NLPs. The mechanical parameters of NFs depend on the concentration of NLPs. The NFs incorporated with G‐loaded NLPs showed inhibition activity against four foodborne pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium) with an inhibition zone of 4.5–22 mm. Moreover, the α‐diphenyl‐β‐picrylhydrazyl (DPPH) scavenging activity of NFs samples was located at the range of 20%–48%. These findings represent the Efficiency of the G‐loaded NLPs for use as bioactive compound in the zein‐based NFs as an active packaging material.

Metabolic Regulation of Longevity and Immune Response in Caenorhabditis elegans by Ingestion of Lacticaseibacillus rhamnosus IDCC 3201 Using Multi-Omics Analysis.

Probiotics, specifically Lacticaseibacillus rhamnosus, have garnered attention for their potential health benefits. This study focuses on evaluating the probiotic properties of candidate probiotics L. rhamnosus IDCC 3201 (3201) using the Caenorhabditis elegans surrogate animal model, a well-established in vivo system for studying host-bacteria interactions. The adhesive ability to the host's gastrointestinal tract is a crucial criterion for selecting potential probiotic bacteria. Our findings demonstrated that 3201 exhibits significantly higher adhesive capabilities compared with Escherichia coli OP50 (OP50), a standard laboratory food source for C. elegans and is comparable with the widely recognized probiotic L. rhamnosus GG (LGG). In lifespan assay, 3201 significantly increased the longevity of C. elegans compared with OP50. In addition, preconditioning with 3201 enhanced C. elegans immune response against four different foodborne pathogenic bacteria. To uncover the molecular basis of these effects, transcriptome analysis elucidated that 3201 modulates specific gene expression related to the innate immune response in C. elegans. C-type lectin-related genes and lysozyme-related genes, crucial components of the immune system, showed significant upregulation after feeding 3201 compared with OP50. These results suggested that preconditioning with 3201 may enhance the immune response against pathogens. Metabolome analysis revealed increased levels of fumaric acid and succinic acid, metabolites of the citric acid cycle, in C. elegans fed with 3201 compared with OP50. Furthermore, there was an increase in the levels of lactic acid, a well-known antimicrobial compound. This rise in lactic acid levels may have contributed to the robust defense mechanisms against pathogens. In conclusion, this study demonstrated the probiotic properties of the candidate probiotic L. rhamnosus IDCC 3201 by using multi-omics analysis.

Zinc oxide nanoparticles reinforced gelatin/starch bio‐nanocomposite film for UV‐ray protection and antimicrobial resistance

AbstractThe research aimed to prepare eco‐friendly bio‐nanocomposite films utilizing gelatin/starch (GS), nano‐ZnO, and Darbha grass extract via the solution casting method. Then, it was examined the mechanical and physical properties of different durations of sunlight exposure on the prepared films. The results indicated that up to 12 h of sunlight exposure led to increased film thickness, mechanical strength, and apparent density. Tensile strength increased from 4.8 to 34.8 MPa, and the average crystalline size of the nanoparticles was found to be 54.35 nm using scanning electron microscope. Compared with GS films, these bio‐nanocomposite films exhibited lower moisture content, oil permeability, and enhanced water barrier properties. Moreover, they displayed significant UV absorption and profound antimicrobial activity against both gram‐positive and gram‐negative food borne pathogenic bacteria. The nano‐ZnO/Darbha grass extract‐based bio‐nanocomposite films exhibited showed improved characteristics and could be applied in the field of food packaging application.

Molecularly imprinted polymer combined with MOF-assisted redox recycling amplification: A powerful electrochemical sensing strategy for pathogenic bacteria

Rapid and sensitive determination of foodborne pathogenic bacteria at a low cost is crucial for ensuring food safety monitoring and diagnosing bacterial infections. In this protocol, we propose an electrochemical sandwich-type biosensor for highly sensitive detection of bacteria based on a bacterial imprinted polymer film (BIF) and metal-organic frameworks (MOF)-assisted redox recycling amplification. The BIF is formed in-situ through electropolymerization (EP) and template removal on the electrode surface, while aptamers are assembled on nanogold-modified MOF to create signal nanoprobes with target recognition ability. The BIF-modified electrode effectively captures the target bacteria and subsequently forms a sandwich structure through conjugation with signal nanoprobes, enabling efficient adsorption of methylene blue (MB). This facilitates the redox recycling of Fe(II) from the electroactive [Fe(CN)6]3-/4- in testing buffer assisted by MB, thereby generating a significantly amplified anodic current of [Fe(CN)6]3-/4- for precise quantitation. By utilizing the selective BIF interface and MOF-assisted redox recycling amplification, our method demonstrates excellent analytical performance with a low limit of detection (LOD) of 1 CFU mL−1, a broad detection range spanning from 10 to 108 CFU mL−1, and high selectivity. The feasibility of applying this approach for detecting bacteria in complex samples highlights its significant potential in areas related to food safety and public health.

Rapid Nucleic Acid Detection of Listeria monocytogenes Based on RAA-CRISPR Cas12a System.

Listeria monocytogenes (L. monocytogenes) is a food-borne pathogenic bacteria that frequently contaminates animal-derived food and low-temperature preserved food. Listeriosis caused by its infection has a high mortality rate and poses a serious threat to human health. Therefore, it is crucial to establish a sensitive, rapid and easy-to-operate technique. In this study, a Recombinase Aided Amplification (RAA) assisted CRISPR/Cas12a (RAA-CRISPR/Cas12a) fluorescence platform was established for highly sensitive nucleic acid detection of L. monocytogenes. The established RAA-CRISPR/Cas12a showed high sensitivity and high specificity, with the sensitivity of 350 CFU/mL and 5.4 × 10-3 ng/μL for pure bacterial solution and genomic DNA, and good specificity for 5 strains of Listeria spp. and 14 strains of other common pathogenic bacteria. L. monocytogenes could be detected at an initial concentration of 2.3 CFU/25g within 2 h of enriching the beef in the food matrix, and this method could be applied to food samples that were easily contaminated with L. monocytogenes The results of RAA-CRISPR/Cas12a could be observed in 5 min, while the amplification was completed in 20-30 min. The speed and sensitivity of RAA-CRISPR/Cas12a were significantly higher than that of the national standard method. In conclusion, the RAA-CRISPR/Cas12a system established in this study has new application potential in the diagnosis of food-borne pathogens.

Mesoporous Silica Nanoparticles-Enhanced Microarray Technology for Highly Sensitive Simultaneous Detection of Multiplex Foodborne Pathogens.

Ensuring food safety is paramount for the food industry and global health concerns. In this study, we have developed a method for the detection of prevalent foodborne pathogenic bacteria, including Escherichia coli, Salmonella spp., Listeria spp., Shigella spp., Campylobacter spp., Clostridium spp., and Vibrio spp., utilizing antibody-aptamer arrays. To enhance the fluorescence signals on the microarray, the mesoporous silica nanoparticles (MSNs) conjugated with fluorescein, streptavidin, and seven detection antibodies-biotin were employed, forming fluorescein doped mesoporous silica nanoparticles conjugated with detection antibodies (MSNs-Flu-SA-Abs) complexes. The array pattern was designed for easy readability and enabled the simultaneous detection of all seven foodborne pathogens, referred to as the 7FP-biochip. Following the optimization of MSNs-Flu-SA-Abs complexes attachment and enhancement of the detection signal in fluorescent immunoassays, a high level of sensitivity was achieved. The detection limits for the seven pathogens in both buffer and food samples were 102 CFU/mL through visual screening, with fluorescent intensity quantification achieving levels as low as 20-34 CFU/g were achieved on the antibody-aptamer arrays. Our antibody-aptamer array offers several advantages, including significantly reduced nonspecific binding with no cross-reaction between bacteria. Importantly, our platform detection exhibited no cross-reactivity among the tested bacteria in this study. The multiplex detection of foodborne pathogens in canned tuna samples with spiked bacteria was successfully demonstrated in real food measurements. In conclusion, our study presents a promising method for detecting multiple foodborne pathogens simultaneously. With its high sensitivity and specificity, the developed antibody-aptamer array holds great potential for enhancing food safety and public health.

Comparative analysis of the application efficiency of gold nanoparticles-based SERS in four foodborne pathogenic microbes

It has been widely reported that SERS can detect foodborne pathogenic bacteria, but SERS has only been limited to the detection of purified single bacteria. However, there’s few single bacterial infections in the natural state were found at the most time, and rare comparative investigations of different Gram-negative and Gram-positive bacteria by SERS exist. At the present study, we are aiming at the comparative analysis of the detection efficiency toward different foodborne pathogenic microbes by a conventional citrate-reduced gold colloid, including Escherichia coli, Salmonella enteritidis, Staphylococcus aureus and Listeria monocytogenes. The SERS spectra of samples were collected with sterile 0.5% NaCl solution as aggregating compound. First, the stability of each bacterial were detected with gold nanoparticles. Afterward, SERS signals of the four bacteria were compared at different concentrations, and it was found that Gram-positive and Gram-negative bacteria have different minimum sensitivity and detection stability. Next, the mixed bacterial SERS detection was applied to classify and identify the similar Raman spectra. Spectral data were analyzed using multivariate data analysis methods, including principal component analysis (PCA) and hierarchical cluster analysis (HCA). The SERS procedure we proposed, which utilized gold nanoparticles adsorbing on bacteria and multivariate analysis, allowed differentiation of species. The results of this pilot study demonstrate the potential of SERS to rapidly identify Gram-negative and Gram-positive foodborne pathogens.

Lactobacillus-derived components for inhibiting biofilm formation in the food industry.

Biofilm, a microbial community formed by especially pathogenic and spoilage bacterial species, is a critical problem in the food industries. It is an important cause of continued contamination by foodborne pathogenic bacteria. Therefore, removing biofilm is the key to solving the high pollution caused by foodborne pathogenic bacteria in the food industry. Lactobacillus, a commonly recognized probiotic that is healthy for consumer, have been proven useful for isolating the potential biofilm inhibitors. However, the addition of surface components and metabolites of Lactobacillus is not a current widely adopted biofilm control strategy at present. This review focuses on the effects and preliminary mechanism of action on biofilm inhibition of Lactobacillus-derived components including lipoteichoic acid, exopolysaccharides, bacteriocins, secreted protein, organic acids and some new identified molecules. Further, the review discusses several modern biofilm identification techniques and particularly interesting new technology of biofilm inhibition molecules. These molecules exhibit stronger inhibition of biofilm formation, playing a pivotal role in food preservation and storage. Overall, this review article discusses the application of biofilm inhibitors produced by Lactobacillus, which would greatly aid efforts to eradicate undesirable bacteria from environment in the food industries.

Duality Effect of Bee Products in Dealing with Yoghurt Starter, Probiotics and Food Borne Pathogenic Bacteria

Duality Effect of Bee Products in Dealing with Yoghurt Starter, Probiotics and Food Borne Pathogenic Bacteria

BACTERIOCIN PRODUCED BY LACTIC ACID BACTERIA: A PROBIOTIC

Chemical preservatives, usually used during the long period, to protect the food materials by controlling undesirable bacteria and harmful spoiler, have been proved as toxic to human health. Conscious consumers have serious awareness to purchase safe foods without chemical additives. In the recent years, bio-preservation is gained increasing attention to harmonize consumer demands along with standard food quality. Various attempts are growing on the use of micro-organisms or their antimicrobial metabolites for the protection of food products. The bacteriocins produced by lactic acid bacteria (LAB) have a relatively broad antimicrobial spectrum against variety of food-borne pathogenic and spoilage bacteria. Bacteriocin-producing lactic acid bacteria or bacteriocins can be used in foods as bio-preservatives. The review is focused on bacteriocin produced by lactic acid bacteria.

Microscopic identification of foodborne bacterial pathogens based on deep learning method

Accurate and rapid detection of foodborne bacterial pathogens is critical for food quality control. Nowadays, tracking morphological bacterial properties using microscope is still a priority at the grass-roots food supervision department due to its simplicity and low cost. However, the method requires highly professional personnel and there are certain misjudgments in the process of analysis. Automatically recognizing foodborne pathogen using deep learning algorithm to replace manual microscopy will not only reduce expert cost, artificial misjudgment, and operation time in detection, but also provide more objective and accurate identification. Here, we firstly constructed a high-quality and large-scale dataset of foodborne pathogenic bacteria, allowing the deep learning-based model to be efficiently trained and achieve accurate identification. The deep convolutional neural network-based model is capable of identifying six common foodborne pathogens, including Escherichia coli (O157:H7), Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus, Salmonella typhi, and Streptococcus hemolyticus, with accuracy rates of 90%–100%. This method can assist or replace the manual microscopic inspection step in traditional detection methods, and is promising to break through the traditional approach that heavily relies on manual judgment, greatly reduce the cost of experts and human errors, and provide rapid, accurate, and powerful discriminatory results in large quantities for detection.

Characterization and technological functions of different lactic acid bacteria from traditionally produced Kırklareli white brined cheese during the ripening period.

In the present study, the evolution of the physicochemical and microbiological characteristics of lactic acid bacteria (LAB) in traditional Kırklareli white brined cheese collected from 14 different cheese manufacturing facilities were investigated on different days of the 90-day ripening period. The obtained LAB within the species Lactococcus (Lc.) lactis, Latilactobacillus (Lt.) curvatus, Lactobacillus (Lb.) casei and Lb. plantarum, Enterococcus (E.) durans, E. faecium, E. faecalis, Streptococcus macedonicus, and Weissella paramesenteroides were characterized in terms of their influence on technological properties and their potential as starter cultures for traditional white brined cheese production. The results of the microbiological and physicochemical investigations showed that a few selected isolates of Lc. lactis, Lb. casei, and Lb. plantarum had certain functions as starter germs. Moderate acidification capacity, antibacterial activity and proteolytic activity, which are characteristic of their use as starter lactic acid bacteria, were found. Importantly, antibiotic resistance among selected Lc. lactis, Lb. casei, and Lb. plantarum isolates was extremely low, whereas some of these isolates demonstrated antibacterial activity against major foodborne pathogenic bacteria. Based on the results obtained in this study, selected Lc. and Lb. isolates can also be considered as starter culture in traditional cheese production.