Review of multi-species biofilm formation from foodborne pathogens: multi-species biofilms and removal methodology

Antimicrobial resistance induction potential of grapefruit seed extract on multi-species biofilm of E. coli in food industry

Biofilm formation in natural environments involving complex multi-structural arrangements hinders challenges in antimicrobial resistance. This study investigated the antimicrobial resistance potential of grapefruit seed extract (GSE) by examining the formation of mono-, dual-, and multi-species biofilms. We also explored the counterintuitive effect in response to GSE at various concentrations, including minimum inhibitory concentration (MIC) and sub-MIC (1/2 and 1/4 MIC). The results of the swimming and swarming motility tests revealed increased motility at the sub-MIC of GSE. The crystal violet assay demonstrated increased biofilm formation in multi-species biofilms, highlighting the synergistic effect of Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes. At the MIC concentration of GSE, field emission scanning electron microscopy (FE-SEM) revealed cell morphology damage, while sub-MIC increased biofilm formation and architectural complexity. Multi-species biofilms demonstrated greater biofilm-forming ability and antimicrobial resistance than mono-species biofilms, indicating synergistic interactions and enhanced resilience. These findings highlight the importance of understanding biofilm dynamics and antimicrobial resistance to ensure environmental safety.

Guardians of Future Food Safety: Innovative Applications and Advancements in Anti-biofouling Materials

Biofilm formation is a widespread natural phenomenon that poses a substantial threat to food microbiological safety, with direct implications for consumer health. To combat this challenge effectively, one promising strategy involves the development of functional anti-biofouling layers on food-contact surfaces to deter microbial adhesion. Herein, we explore the methodologies for fabricating both hydrophilic and hydrophobic anti-biofouling materials, along with a detailed examination of their inherent antiadhesive mechanisms. Furthermore, we provide concise insights into exemplary applications of anti-biofouling materials within the context of the food industry. This comprehensive analysis not only advances our understanding of biofilm prevention but also sets the stage for innovative developments in anti-biofouling materials and their future applications in food science. These advancements hold the potential to significantly enhance food microbiological safety, ensuring that consumers can confidently enjoy food products of the highest standards in terms of hygiene and quality.

Microbial Biofilms: Features of Formation and Potential for Use in Bioelectrochemical Devices

Microbial biofilms present one of the most widespread forms of life on Earth. The formation of microbial communities on various surfaces presents a major challenge in a variety of fields, including medicine, the food industry, shipping, etc. At the same time, this process can also be used for the benefit of humans-in bioremediation, wastewater treatment, and various biotechnological processes. The main direction of using electroactive microbial biofilms is their incorporation into the composition of biosensor and biofuel cells This review examines the fundamental knowledge acquired about the structure and formation of biofilms, the properties they have when used in bioelectrochemical devices, and the characteristics of the formation of these structures on different surfaces. Special attention is given to the potential of applying the latest advances in genetic engineering in order to improve the performance of microbial biofilm-based devices and to regulate the processes that take place within them. Finally, we highlight possible ways of dealing with the drawbacks of using biofilms in the creation of highly efficient biosensors and biofuel cells.

Controlling of foodborne pathogen biofilms on stainless steel by bacteriophages: A systematic review and meta-analysis

This study investigates the potential of using bacteriophages to control foodborne pathogen biofilms on stainless steel surfaces in the food industry. Biofilm-forming bacteria can attach to stainless steel surfaces, rendering them difficult to eradicate even after a thorough cleaning and sanitizing procedures. Bacteriophages have been proposed as a possible solution, as they can penetrate biofilms and destroy bacterial cells within, reducing the number of viable bacteria and preventing the growth and spread of biofilms. This systematic review and meta-analysis evaluates the potential of bacteriophages against different biofilm-forming foodborne bacteria, including Cronobacter sakazakii, Escherichia coli, Staphylococcus aureus, Pseudomonas fluorescens, Pseudomonas aeruginosa and Listeria monocytogenes. Bacteriophage treatment generally causes a significant average reduction of 38 % in biofilm formation of foodborne pathogens on stainless steel. Subgroup analyses revealed that phages are more efficient in long-duration treatment. Also, applying a cocktail of phages is 1.26-fold more effective than applying individual phages. Phages at concentrations exceeding 107 PFU/ml are significantly more efficacious in eradicating bacteria within a biofilm. The antibacterial phage activity decreases substantially by 3.54-fold when applied at 4 °C compared to temperatures above 25 °C. This analysis suggests that bacteriophages can be a promising solution for controlling biofilms in the food industry.

Elimination of Pathogen Biofilms via Postbiotics from Lactic Acid Bacteria: A Promising Method in Food and Biomedicine

Pathogenic biofilms provide a naturally favorable barrier for microbial growth and are closely related to the virulence of pathogens. Postbiotics from lactic acid bacteria (LAB) are secondary metabolites and cellular components obtained by inactivation of fermentation broth; they have a certain inhibitory effect on all stages of pathogen biofilms. Postbiotics from LAB have drawn attention because of their high stability, safety dose parameters, and long storage period, which give them a broad application prospect in the fields of food and medicine. The mechanisms of eliminating pathogen biofilms via postbiotics from LAB mainly affect the surface adhesion, self-aggregation, virulence, and QS of pathogens influencing interspecific and intraspecific communication. However, there are some factors (preparation process and lack of target) which can limit the antibiofilm impact of postbiotics. Therefore, by using a delivery carrier and optimizing process parameters, the effect of interfering factors can be eliminated. This review summarizes the concept and characteristics of postbiotics from LAB, focusing on their preparation technology and antibiofilm effect, and the applications and limitations of postbiotics in food processing and clinical treatment are also discussed.

Drug-loaded lipid nanoparticles improve the removal rates of the Staphylococcus aureus biofilm

Biofilms of the foodborne pathogen Staphylococcus aureus show improved resistance to antibiotics and are difficult to eliminate. To enhance antibacteria and biofilm dispersion via extracellular matrix diffusion, a new lipid nanoparticle was prepared, which employed a mixture of phospholipids and a 0.8% surfactin shell. In the lipid nanoparticle, 31.56 μg mL-1 of erythromycin was encapsulated. The lipid nanoparticle size was approximately 52 nm and the zeta-potential was -67 mV, which was measured using a Marvin laser particle size analyzer. In addition, lipid nanoparticles significantly dispersed the biofilms of S. aureus W1, CICC22942, and CICC 10788 on the surface of stainless steel, reducing the total viable count of bacteria in the biofilms by 103 CFU mL-1 . In addition, the lipid nanoparticle can remove polysaccharides and protein components from the biofilm matrix. The results of laser confocal microscopy showed that the lipid nanoparticles effectively killed residual bacteria in the biofilms. Thus, to thoroughly eliminate biofilms on material surfaces in food factories to avoid repeated contamination, drug-lipid nanoparticles present a suitable method to achieve this.

A review of mechanism analysis methods in multi-species biofilm of foodborne pathogens

Biofilms are an aggregation of microorganisms that have high resistance to antimicrobial agents. In the food industry, it has been widely studied that foodborne pathogens on both food surfaces and food-contact surfaces can form biofilms thereby threatening the safety of the food. In the natural environment, multi-species biofilms formed by more than two different microorganisms are abundant. In addition, the resistance of multi-species biofilms to antimicrobial agents is higher than that of mono-species biofilms. Therefore, studies to elucidate the mechanisms of multi-species biofilms formed by foodborne pathogens are still required in the food industry. In this review paper, we summarized the novel analytical methods studied to evaluate the mechanisms of multi-species biofilms formed by foodborne pathogens by dividing them into four categories: spatial distribution, bacterial interaction, extracellular polymeric substance production and quorum sensing analytical methods.

Antibiofilm Activity and Mechanism of Linalool against Food Spoilage Bacillus amyloliquefaciens

Pellicle biofilm-forming bacteria Bacillus amyloliquefaciens are the major spoilage microorganisms of soy products. Due to their inherent resistance to antibiotics and disinfectants, pellicle biofilms formed are difficult to eliminate and represent a threat to food safety. Here, we assessed linalool's ability to prevent the pellicle of two spoilage B. amyloliquefaciens strains. The minimum biofilm inhibitory concentration (MBIC) of linalool against B. amyloliquefaciens DY1a and DY1b was 4 μL/mL and 8 μL/mL, respectively. The MBIC of linalool had a considerable eradication rate of 77.15% and 83.21% on the biofilm of the two strains, respectively. Scanning electron microscopy observations revealed that less wrinkly and thinner pellicle biofilms formed on a medium supplemented with 1/2 MBIC and 1/4 MBIC linalool. Also, linalool inhibited cell motility and the production of extracellular polysaccharides and proteins of the biofilm matrix. Furthermore, linalool exposure reduced the cell surface hydrophobicity, zeta potential, and cell auto-aggregation of B. amyloliquefaciens. Molecular docking analysis demonstrated that linalool interacted strongly with quorum-sensing ComP receptor and biofilm matrix assembly TasA through intermolecular hydrogen bonds, hydrophobic contacts, and van der Waals forces interacting with site residues. Overall, our findings suggest that linalool may be employed as a potential antibiofilm agent to control food spoilage B. amyloliquefaciens.

Catheter-Based Medical Device Biofilm Ablation Using Histotripsy: A Parameter Study

OBJECTIVE

Biofilm formation in medical catheters is a major source of hospital-acquired infections which can produce increased morbidity and mortality for patients. Histotripsy is a non-invasive, non-thermal focused ultrasound therapy and recently has been found to be effective at removal of biofilm from medical catheters. Previously established histotripsy methods for biofilm removal, however, would require several hours of use to effectively treat a full-length medical catheter. Here, we investigate the potential to increase the speed and efficiency with which biofilms can be ablated from catheters using histotripsy.

METHODS

Pseudomonas aeruginosa (PA14) biofilms were cultured in in vitro Tygon catheter mimics and treated with histotripsy using a 1 MHz histotripsy transducer and a variety of histotripsy pulsing rates and scanning methods. The improved parameters identified in these studies were then used to explore the bactericidal effect of histotripsy on planktonic PA14 suspended in a catheter mimic.

RESULTS

Histotripsy can be used to remove biofilm and kill bacteria at substantially increased speeds compared with previously established methods. Near-complete biofilm removal was achieved at treatment speeds up to 1 cm/s, while a 4.241 log reduction in planktonic bacteria was achieved with 2.4 cm/min treatment.

CONCLUSION

These results represent a 500-fold increase in biofilm removal speeds and a 6.2-fold increase in bacterial killing speeds compared with previously published methods. These findings indicate that histotripsy shows promise for the treatment of catheter-associated biofilms and planktonic bacteria in a clinically relevant time frame.

Alterations in Antibiotic Susceptibility of Staphylococcus aureus and Klebsiella pneumoniae in Dual Species Biofilms

In the last decades, it has been shown that biofilm-associated infections in most cases are caused by rather two or even more pathogens than by single microorganisms. Due to intermicrobial interactions in mixed communities, bacteria change their gene expression profile, in turn leading to alterations in the biofilm structure and properties, as well as susceptibility to antimicrobials. Here, we report the alterations of antimicrobials efficiency in mixed biofilms of Staphylococcus aureus-Klebsiella pneumoniae in comparison with mono-species biofilms of each counterpart and discuss possible mechanisms of these alterations. In cell clumps detached from dual-species biofilms, S. aureus became insensitive to vancomycin, ampicillin, and ceftazidime compared to solely S. aureus cell clumps. In turn, the increased efficiency of amikacin and ciprofloxacin against both bacteria could be observed, compared to mono-species biofilms of each counterpart. Scanning electron microscopy and confocal microscopy indicate the porous structure of the dual-species biofilm, and differential fluorescent staining revealed an increased number of polysaccharides in the matrix, in turn leading to more loose structure and thus apparently providing increased permeability of the dual-species biofilm to antimicrobials. The qRT-PCR showed that ica operon in S. aureus became repressed in mixed communities, and polysaccharides are produced mainly by K. pneumoniae. While the molecular trigger of these changes remains undiscovered, detailed knowledge of the alterations in antibiotic susceptibility to given drugs opens doors for treatment correction options for S. aureus-K. pneumoniae biofilm-associated infections.

Novel Antibacterial Metals as Food Contact Materials: A Review

Food contamination caused by microorganisms is a significant issue in the food field that not only affects the shelf life of food, but also threatens human health, causing huge economic losses. Considering that the materials in direct or indirect contact with food are important carriers and vectors of microorganisms, the development of antibacterial food contact materials is an important coping strategy. However, different antibacterial agents, manufacturing methods, and material characteristics have brought great challenges to the antibacterial effectiveness, durability, and component migration associated with the use security of materials. Therefore, this review focused on the most widely used metal-type food contact materials and comprehensively presents the research progress regarding antibacterial food contact materials, hoping to provide references for exploring novel antibacterial food contact materials.

Targeted pH-responsive chitosan nanogels with Tanshinone IIA for enhancing the antibacterial/anti-biofilm efficacy

Persistent bacterial infection caused by biofilms is one of the most serious problems that threatened human health. The development of antibacterial agents remains a challenge to penetrate biofilm and effectively treat the underlying bacterial infection. In the current study, chitosan-based nanogels were developed for encapsulating the Tanshinone IIA (TA) to enhance the antibacterial and anti-biofilm efficacy against Streptococcus mutans (S. mutans). The as-prepared nanogels (TA@CS) displayed excellent encapsulation efficiency (91.41 ± 0.11 %), uniform particle sizes (393.97 ± 13.92 nm), and enhanced positive potential (42.27 ± 1.25 mV). After being coated with CS, the stability of TA under light and other harsh environments was greatly improved. In addition, TA@CS displayed pH responsiveness, allowing it to selectively release more TA in acidic conditions. Furthermore, the positively charged TA@CS were equipped to target negatively charged biofilm surfaces and efficiently penetrate through biofilm barriers, making it promising for remarkable anti-biofilm activity. More importantly, when TA was encapsulated into CS nanogels, the antibacterial activity of TA was enhanced at least 4-fold. Meanwhile, TA@CS inhibited 72 % of biofilm formation at 500 μg/mL. The results demonstrated that the nanogels constituted CS and TA had antibacterial/anti-biofilm properties with synergistic enhanced effects, which will benefit pharmaceutical, food, and other fields.

Recent Nanotechnologies to Overcome the Bacterial Biofilm Matrix Barriers

Bacterial biofilm-related infectious diseases severely influence human health. Under typical situations, pathogens can colonize inert or biological surfaces and form biofilms. Biofilms are functional aggregates that coat bacteria with extracellular polymeric substances (EPS). The main reason for the failure of biofilm infection treatment is the low permeability and enrichment of therapeutic agents within the biofilm, which results from the particular features of biofilm matrix barriers such as negatively charged biofilm components and highly viscous compact EPS structures. Hence, developing novel therapeutic strategies with enhanced biofilm penetrability is crucial. Herein, the current progress of nanotechnology methods to improve therapeutic agents' penetrability against biofilm matrix, such as regulating material morphology and surface properties, utilizing the physical penetration of nano/micromotors or microneedle patches, and equipping nanoparticles with EPS degradation enzymes or signal molecules, is first summarized. Finally, the challenges, perspectives, and future implementations of engineered delivery systems to manage biofilm infections are presented in detail.

Dry surface biofilms in the food processing industry: An overview on surface characteristics, adhesion and biofilm formation, detection of biofilms, and dry sanitization methods

Bacterial biofilm formation in low moisture food processing (LMF) plants is related to matters of food safety, production efficiency, economic loss, and reduced consumer trust. Dry surfaces may appear dry to the naked eye, however, it is common to find a coverage of thin liquid films and microdroplets, known as microscopic surface wetness (MSW). The MSW may favor dry surface biofilm (DSB) formation. DSB formation is similar in other industries, it occurs through the processes of adhesion, production of extracellular polymeric substances, development of microcolonies and maturation, it is mediated by a quorum sensing (QS) system and is followed by dispersal, leading to disaggregation. Species that survive on dry surfaces develop tolerance to different stresses. DSB are recalcitrant and contribute to higher resistance to sanitation, becoming potential sources of contamination, related to the spoilage of processed products and foodborne disease outbreaks. In LMF industries, sanitization is performed using physical methods without the presence of water. Although alternative dry sanitizing methods can be efficiently used, additional studies are still required to develop and assess the effect of emerging technologies, and to propose possible combinations with traditional methods to enhance their effects on the sanitization process. Overall, more information about the different technologies can help to find the most appropriate method/s, contributing to the development of new sanitization protocols. Thus, this review aimed to identify the main characteristics and challenges of biofilm management in low moisture food industries, and summarizes the mechanisms of action of different dry sanitizing methods (alcohol, hot air, UV-C light, pulsed light, gaseous ozone, and cold plasma) and their effects on microbial metabolism.

Factors Influencing Biofilm Formation by Salmonella enterica sv. Typhimurium, E. cloacae, E. hormaechei, Pantoea spp., and Bacillus spp. Isolated from Human Milk Determined by PCA Analysis

Bacteria enter milk during poor hygiene practices and can form a biofilm on surfaces that come into contact with human milk. The presence of a biofilm increases the risk of infections among newborns as bacteria protected by biofilm are resistant to washing and disinfection processes. The formation of the biofilm depends on the microbial species, environmental conditions, and the specific materials colonized. The aim of this study is to analyze the effects of factors such as temperature, incubation time, and initial cell concentration on biofilm formation by pathogenic bacteria isolated from human milk on model hydrophobic polystyrene surfaces. Model studies confirm that pathogenic bacteria appearing in human milk as a result of cross-contamination tend to form a biofilm. The majority of isolates formed biofilm at both 25 and 37 °C after 12 h at 1 × 10³ CFU/mL inoculum count. Multivariate principal component analysis (PCA) showed that at lower temperatures, biofilm formation by bacterial isolates was the main determinant of biofilm formation, other factors were less important; however, at 37 °C, time was a factor in biofilm formation. The model research performed underlines the importance of maintaining the proper hygiene of rooms, surfaces, and devices for expressing, storing, and preparing mothers' milk and powdered infant formula (PIF) in facilities responsible for feeding newborns and premature babies.

The effect of a spontaneous induction prophage, phi458, on biofilm formation and virulence in avian pathogenic Escherichia coli

Prophage sequences are present in most bacterial genomes and account for up to 20% of its host genome. Integration of temperate phages may have an impact on the expression of host genes, while some prophages could turn into the lytic cycle and affect bacterial host biological characteristics. We investigated the role of spontaneous induction prophages in avian pathogenic Escherichia coli (APEC), which is the causative agent of avian colibacillosis in poultry, and considered a potential zoonotic bacterium related to the fact it serves as an armory of extraintestinal pathogenic E. coli. We found that APEC strain DE458 had a high spontaneous induction rate in vivo and in vitro. The released phage particles, phi458, were isolated, purified, and sequenced, and the deletion mutant, DE458Δphi458, was constructed and characterized. Biofilm formation of DE458Δphi458 was strongly decreased compared to that of the wild-type strain (p < 0.01). In addition, while the addition of DNase (100 μg/ml) did not affect prophage release but could digest eDNA, it significantly reduced the biofilm production of DE458 biofilm to a level close to that of DE458Δphi458. Compared to DE458, the adhesion and invasion abilities of DE458Δphi458 increased by approximately 6-20 times (p < 0.05). The virulence of DE458Δphi458 was enhanced by approximately 10-fold in chickens based on a 50% lethal dose. Furthermore, avian infection assays showed that the bacterial loads of DE458Δphi458 in the lung and liver were increased by 16.5- and 10-fold (p < 0.05), respectively, compared with those of the WT strain. The qRT-PCR revealed that deletion of phi458 led to upregulation of type I fimbriate-related gene fimH and curli-related gene csgC by 3- and 2.8-fold, respectively (p < 0.01). Our study revealed that phi458 promoted biofilm formation by spontaneously inducing and decreasing virulence by repressing virulence genes.

Dual-Species Biofilms Formed by Escherichia coli and Salmonella Enhance Chlorine Tolerance

Outbreaks of Escherichia coli and Salmonella in food might be associated with the cross-contamination of biofilms on food-contact surfaces. The knowledge of the sanitization of mono-species biofilm on the food-contact surface is well established, while mixed-species biofilm occurs more naturally, which could profoundly affect the efficacy of sanitizer.

Genomic characterization of a novel bacteriophage STP55 revealed its prominent capacity in disrupting the dual-species biofilm formed by Salmonella Typhimurium and Escherichia coli O157: H7 strains

Salmonella and Escherichia coli are important foodborne pathogens, forming bacterial biofilms that contribute to their virulence, antimicrobial resistance, and survival on surfaces. Broad lytic phages are promising alternatives to conventional technologies for pathogen biocontrol and reducing biofilms. Herein, we isolated and characterized a novel polyvalent phage STP55 that not only lyse some serotypes of Salmonella, but also some E. coli strains. It had a wide range of pH (4-12) and thermal (30-60 °C) tolerances. The latent time was determined to be 10 min in the one-step growth experiment. Morphological observations by transmission electron microscopy and phylogenetic analysis using terminase gene classified STP55 to family Ackermannviridae in the order Caudovirales, with a complex tail structure. The genome was found to comprise 157,708 bp double-stranded DNA, with 44.57% GC content, 207 predicted ORFs and with no genes associated with antibiotic resistance, toxins, lysogeny, and virulence factors. Particularly, phage STP55 was able to inhibit single- and dual-species biofilms formation by S. Typhimurium ATCC 14028 and E. coli O157: H7, with a reduction percentage of 51.0%, 47.8% and 52.8%, respectively. Moreover, more than 65.0%, 72.9% and 46.2% of an established, single- and dual-species biofilms by S. Typhimurium ATCC 14028 and E. coli O157: H7 were removed after 8 h exposure to the phage STP55, respectively. The elimination effect of STP55 on dual-species biofilm formed on lettuce was further observed by SEM. Overall, our results demonstrated that STP55 is a promising antimicrobial against Salmonella and E. coli.

Microbial resistance to sanitizers in the food industry: review

Hygiene programs which comprise the cleaning and sanitization steps are part of the Good Hygiene Practices (GHP) and are considered essential to ensure food safety and quality. Inadequate hygiene practices may contribute to the occurrence of foodborne diseases, development of microbial resistance to sanitizers, and economic losses. In general, the sanitizer resistance is classified as intrinsic or acquired. The former is an inherent characteristic, naturally present in some microorganisms, whereas the latter is linked to genetic modifications that can occur at random or after continuous exposure to a nonnormal condition. The resistance mechanisms can involve changes in membrane permeability or in the efflux pump, and enzymatic activity. The efflux pump mechanism is the most elucidated in relation to the resistance caused by the use of different types of sanitizers. In addition, microbial resistance to sanitizers can also be favored in the presence of biofilms due to the protection given by the glycocalyx matrix and genetic changes. Therefore, this review aimed to show the main microbial resistance mechanisms to sanitizers, including genetic modifications, biofilm formation, and permeability barrier.

Novel Antibiofilm Inhibitor Ginkgetin as an Antibacterial Synergist against Escherichia coli

As an opportunistic pathogen, Escherichia coli (E. coli) forms biofilm that increases the virulence of bacteria and antibiotic resistance, posing a serious threat to human and animal health. Recently, ginkgetin (Gin) has been discovered to have antiinflammatory, antioxidant, and antitumor properties. In the present study, we evaluated the antibiofilm and antibacterial synergist of Gin against E. coli. Additionally, Alamar Blue assay combined with confocal laser scanning microscope (CLSM) and crystal violet (CV) staining was used to evaluate the effect of antibiofilm and antibacterial synergist against E. coli. Results showed that Gin reduces biofilm formation, exopolysaccharide (EPS) production, and motility against E. coli without limiting its growth and metabolic activity. Furthermore, we identified the inhibitory effect of Gin on AI-2 signaling molecule production, which showed apparent anti-quorum sensing (QS) properties. The qRT-PCR also indicated that Gin reduced the transcription of curli-related genes (csgA, csgD), flagella-formation genes (flhC, flhD, fliC, fliM), and QS-related genes (luxS, lsrB, lsrK, lsrR). Moreover, Gin showed obvious antibacterial synergism to overcome antibiotic resistance in E. coli with marketed antibiotics, including gentamicin, colistin B, and colistin E. These results suggested the potent antibiofilm and novel antibacterial synergist effect of Gin for treating E. coli infections.

Microbially-derived cocktail of carbohydrases as an anti-biofouling agents: a 'green approach'

Enzymes, also known as biocatalysts, display vital properties like high substrate specificity, an eco-friendly nature, low energy inputs, and cost-effectiveness. Among their numerous known applications, enzymes that can target biofilms or their components are increasingly being investigated for their anti-biofouling action, particularly in healthcare, food manufacturing units and environmental applications. Enzymes can target biofilms at different levels like during the attachment of microorganisms, formation of exopolymeric substances (EPS), and their disruption thereafter. In this regard, a consortium of carbohydrases that can target heterogeneous polysaccharides present in the EPS matrix may provide an effective alternative to conventional chemical anti-biofouling methods. Further, for complete annihilation of biofilms, enzymes can be used alone or in conjunction with other antimicrobial agents. Enzymes hold the promise to replace the conventional methods with greener, more economical, and more efficient alternatives. The present article explores the potential and future perspectives of using carbohydrases as effective anti-biofilm agents.

Recent development in antibacterial activity and application of nanozymes in food preservation

Nanozymes with excellent broad-spectrum antibacterial properties offers an alternative strategy for food preservation. This review comprehensively summarized the antibacterial mechanisms of nanozymes, including the generation of reactive oxygen species (ROS) and the destruction of biofilms. Besides, the primary factors (size, morphology, hybridization, light, etc.) regulating the antibacterial activity of different types of nanozymes were highlighted in detail, which provided effective guidance on how to design highly efficient antibacterial nanozymes. Moreover, this review presented elaborated viewpoints on the unique applications of nanozymes in food preservation, including the selection of nanozymes loading matrix, fabrication techniques of nanozymes-based antibacterial films/coatings, and the recent advances in the application of nanozymes-based antibacterial films/coatings in food preservation. In the end, the safety issues of nanozymes have also been mentioned. Overall, this review provided new avenues in the field of food preservation and displayed great prospects.

Structure and Signal Regulation Mechanism of Interspecies and Interkingdom Quorum Sensing System Receptors

Quorum sensing (QS) is a signaling mechanism for cell-to-cell communication between bacteria, fungi, and even eukaryotic hosts such as plant and animal cells. Bacteria in real life do not exist as isolated organisms but are found in complex, dynamic, and microecological environments. The study of interspecies QS and interkingdom QS is a valuable approach for exploring bacteria-bacteria interactions and bacteria-host interaction mechanisms and has received considerable attention from researchers. The correct combination of QS signals and receptors is key to initiating the QS process. Compared with intraspecies QS, the signal regulation mechanism of interspecies QS and interkingdom QS is often more complicated, and the distribution of receptors is relatively wide. The present review focuses on the latest progress with respect to the distribution, structure, and signal transduction of interspecies and interkingdom QS receptors and provides a guide for the investigation of new QS receptors in the future.

Antimicrobial and Antibiofilm Effect of ε-Polylysine against Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli in Tryptic Soy Broth and Chicken Juice

ε-Polylysine (ε-PL) is a safe food additive that is used in the food industry globally. This study evaluated the antimicrobial and antibiofilm activity of antibacterial peptides (ε-PL) against food poisoning pathogens detected in chicken (Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli). The results showed that minimum inhibitory concentrations (MICs) ranged between 0.031-1.0 mg/mL, although most bacterial groups (75%) showed MICs of 1.0 mg/mL. The reduction in the cell viability of pathogens due to ε-PL depended on the time and concentration, and 1/2 × MIC of ε-PL killed 99.99% of pathogens after 10 h of incubation. To confirm biofilm inhibition and degradation effects, crystal violet assay and confocal laser scanning microscopy (CLSM) were used. The biofilm formation rates of four bacterial groups (Salmonella, Listeria, E. coli, and multi-species bacteria) were 10.36%, 9.10%, 17.44%, and 21.37% at 1/2 × MIC of ε-PL, respectively. Additionally, when observed under a CLSM, ε-PL was found to induce biofilm destruction and bacterial cytotoxicity. These results demonstrated that ε-PL has the potential to be used as an antibiotic and antibiofilm material for chicken meat processing.