Current pathogenic Escherichia coli foodborne outbreak cases and therapy development

Exploring Possible Ways to Enhance the Potential and Use of Natural Products through Nanotechnology in the Battle against Biofilms of Foodborne Bacterial Pathogens

Biofilms enable pathogenic bacteria to survive in unfavorable environments. As biofilm-forming pathogens can cause rapid food spoilage and recurrent infections in humans, especially their presence in the food industry is problematic. Using chemical disinfectants in the food industry to prevent biofilm formation raises serious health concerns. Further, the ability of biofilm-forming bacterial pathogens to tolerate disinfection procedures questions the traditional treatment methods. Thus, there is a dire need for alternative treatment options targeting bacterial pathogens, especially biofilms. As clean-label products without carcinogenic and hazardous potential, natural compounds with growth and biofilm-inhibiting and biofilm-eradicating potentials have gained popularity as natural preservatives in the food industry. However, the use of these natural preservatives in the food industry is restricted by their poor availability, stability during food processing and storage. Also there is a lack of standardization, and unattractive organoleptic qualities. Nanotechnology is one way to get around these limitations and as well as the use of underutilized bioactives. The use of nanotechnology has several advantages including traversing the biofilm matrix, targeted drug delivery, controlled release, and enhanced bioavailability, bioactivity, and stability. The nanoparticles used in fabricating or encapsulating natural products are considered as an appealing antibiofilm strategy since the nanoparticles enhance the activity of the natural products against biofilms of foodborne bacterial pathogens. Hence, this literature review is intended to provide a comprehensive analysis of the current methods in nanotechnology used for natural products delivery (biofabrication, encapsulation, and nanoemulsion) and also discuss the different promising strategies employed in the recent and past to enhance the inhibition and eradication of foodborne bacterial biofilms.

CAM-21, a novel lytic phage with high specificity towards Escherichia coli O157:H7 in food products

Escherichia coli O157:H7 is a foodborne pathogen that has become a serious global concern for food safety. Despite the application of different traditional biocontrol methods in the food industry, food borne disease outbreaks linked to this organism remain. Due to their high specificity, lytic bacteriophages are promising antimicrobial agents that could be utilized to control pathogens in foods. In this study, a novel Escherichia phage, CAM-21, was isolated from a dairy farm environment. CAM-21 showed targeted host specificity towards various serotypes of Shiga toxin-producing E. coli, including O157:H7, O26, O103, and O145. Morphological analyses revealed that CAM-21 has a polyhedron capsid and a contractile tail with a diameter of about 92.83 nm, and length of about 129.75 nm, respectively. CAM-21 showed a strong inhibitory effect on the growth of E. coli O157:H7, even at a multiplicity of infection (MOI) of as low as 0.001. Phage adsorption and one-step growth analysis indicated that the target pathogen was rapidly lysed by CAM-21 that exhibited a short latent time (20 min). Electron microscopic and genomic DNA analyses suggested that CAM-21 is a lytic phage, classified as a new species in the Tequatrovirus genus of the Myoviridae Family. Based on whole genome sequencing, CAM-21 has a double-stranded DNA with 166,962 bp, 265 open reading frames and 11 tRNA. The genome of CAM-21 did not encode toxins, virulence factors, antibiotic resistance, lysogeny or allergens. Phylogenetic and genomic comparative analyses suggested that CAM-21 is a T4-like phage species. The growth of E. coli O157:H7 was effectively controlled in milk, ground beef and baby spinach at MOIs of 1000 and 10,000. CAM-21 significantly (P ≤ 0.05) reduced the bacterial counts of the treated foods, ranging from 1.4-2.0 log CFU/mL in milk to 1.3-1.4 log CFU/g in ground beef and baby spinach. These findings suggest that the lytic phage, CAM-21, is a potential candidate for controlling E. coli O157:H7 contamination in foods.

Fiber-based food packaging materials in view of bacterial growth and survival capacities

Understanding interactions of bacteria with fiber-based packaging materials is fundamental for appropriate food packaging. We propose a laboratory model to evaluate microbial growth and survival in liquid media solely consisting of packaging materials with different fiber types. We evaluated food contaminating species (Escherichia coli, Staphylococcus aureus, Bacillus cereus), two packaging material isolates and bacterial endospores for their growth abilities. Growth capacities differed substantially between the samples as well as between bacterial strains. Growth and survival were strongest for the packaging material entirely made of recycled fibers (secondary food packaging) with up to 10.8 log₁₀ CFU/ml for the packaging isolates. Among the food contaminating species, B. cereus and E. coli could grow in the sample of entirely recycled fibers with maxima of 6.1 log₁₀ and 8.6 log₁₀ CFU/mL, respectively. Escherichia coli was the only species that was able to grow in bleached fresh fibers up to 7.0 log₁₀ CFU/mL. Staphylococcus aureus perished in all samples and was undetectable after 1-6 days after inoculation, depending on the sample. The packaging material strains were isolated from recycled fibers and could grow only in samples containing recycled fibers, indicating an adaption to this environment. Spores germinated only in the completely recycled sample. Additionally, microbial digestion of cellulose and xylan might not be a crucial factor for growth. This is the first study describing bacterial growth in food packaging materials itself and proposing functionalization strategies toward active food packaging through pH-lowering.

Application of Microfluidics for Bacterial Identification

Bacterial infections continue to pose serious public health challenges. Though anti-bacterial therapeutics are effective remedies for treating these infections, the emergence of antibiotic resistance has imposed new challenges to treatment. Often, there is a delay in prescribing antibiotics at initial symptom presentation as it can be challenging to clinically differentiate bacterial infections from other organisms (e.g., viruses) causing infection. Moreover, bacterial infections can arise from food, water, or other sources. These challenges have demonstrated the need for rapid identification of bacteria in liquids, food, clinical spaces, and other environments. Conventional methods of bacterial identification rely on culture-based approaches which require long processing times and higher pathogen concentration thresholds. In the past few years, microfluidic devices paired with various bacterial identification methods have garnered attention for addressing the limitations of conventional methods and demonstrating feasibility for rapid bacterial identification with lower biomass thresholds. However, such culture-free methods often require integration of multiple steps from sample preparation to measurement. Research interest in using microfluidic methods for bacterial identification is growing; therefore, this review article is a summary of current advancements in this field with a focus on comparing the efficacy of polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), and emerging spectroscopic methods.

Escherichia coli phage phi2013: genomic analysis and receptor identification

Escherichia coli is an important foodborne pathogen that can cause severe human disease. Here, we report the isolation and characterization of the lytic virus phi2013, which is specific for Escherichia coli laboratory strains. Transmission electron microscopy showed that phage phi2013 has an icosahedral head and a long, fragile, noncontractile tail, exhibiting the typical form of a siphovirus. Evidence revealed that the phi2013 genome is a linear double-stranded DNA molecule of 49,833 bp with 79 predicted genes without any known antibiotic resistance genes, virulence factor genes, or integrase genes. Moreover, the conserved outer membrane protein FhuA, which is present in members of several genera of the family Enterobacteriaceae, was identified as the receptor of phage phi2013. To evaluate the potential of phage phi2013 as a biocontrol agent for controlling E. coli contamination, it was tested in several foods, including sterilized milk, ready-to-eat beef, and crisphead lettuce. The data showed that phage phi2013 can efficiently inhibit E. coli growth in the tested foods at 4°C and 25°C. We therefore conclude that phage phi2013 or cocktails containing phi2013 may be used as an antimicrobial agent in extending the shelf-life of food products by effectively controlling the growth of E. coli.

Improving intestinal absorption and antibacterial effect of florfenicol via nanocrystallisation technology

To study the effects of nanocrystallisation technology on the intestinal absorption properties and antibacterial activity of florfenicol (FF). The florfenicol nanocrystals (FF-NC) were prepared by wet grinding and spray drying. Additionally, changes in particle size, charge, morphology, and dissolution of FF-NC in the long-term stability were monitored by laser particle sizer, TEM, SEM, paddle method, and the structure of FF-NC powder was characterised by nuclear magnetic resonance (NMR) test. The antibacterial activity, intestinal absorption and intestinal histocompatibility of FF-NC were investigated by the stiletto, mini broth dilution susceptibility test, in situ single-pass intestinal perfusion (SPIP) and haematoxylin-eosin (H-E) staining. After 12 months of storage, the particle size and zeta potential of FF-NC were 280.43 ± 8.21 nm and -19.64 ± 3.45 mV, and the electron microscopy results showed that FF-NC were nearly circular with no adhesion between particles. In addition, the drug loading, encapsulation efficiency, and dissolution of FF-NC did not change significantly during storage. The inhibition zone of FF-NC against Escherichia coli and Staphylococcus aureus was 21.37 ± 1.70 mm and 25.17 ± 2.47 mm, respectively. Compared with the FF, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of FF-NC are reduced, and the absorption rate constant (K_a) and efficient permeability coefficient (P_eff) of FF-NC in the three intestinal segments were increased by 1.28, 0.25, and 9.10 times and 0.59, 0.17, and 6.0 times, respectively. The results of tissue sections showed that FF-NC had little damage to the small intestinal. Nanocrystallisation technology is an effective method to increase the intestinal absorption and antibacterial activity of FF.

GC-MS Profiling of Naturally Extracted Essential Oils: Antimicrobial and Beverage Preservative Actions

The purpose of this study was to demonstrate the antimicrobial effects of natural essential oils (EO) and determine their preservative action. Eight natural essential oils were tested against Staphylococcus aureus, Escherichia coli, and Candida albicans representing gram positive, gram negative, and fungi, respectively. The plant materials were used in this study viz. Thymus vulgaris—thyme (TV), Mentha virdis (MV), Mentha longifolia (ML), Rosmarinus officinalis—rosemary (RO), Lavandula dentata—lavender (LD), Origanum majorana—oregano (OM), which belong to the Lamiaceae family. The other two plants were Cymbopogon citratus—lemon grass (family Poaceae) (CC), and Eucalyptus globulus (family Myrtaceae) (EG). Employing the disc diffusion susceptibility test, minimum inhibitory and minimum bactericidal concentrations were estimated for each oil, followed by the addition of oils to pasteurized apple juice after microbial induction. The results revealed that thyme oil showed the maximum zone of inhibition against all tested microbes enriched with monoterpenes class viz. eucalyptol (24.3%), thymol (17.4%), and γ-terpinene (15.2%). All other tested oils exhibited a concentration-dependent inhibition of growth and their MIC ranged from 0.1 to 100 µL/mL. The recorded minimum bactericidal concentration values were apparently double the minimum inhibitory concentration. The EO of Mentha virdis followed by Mentha longifolia showed maximum antimicrobial activity against the tested organisms in pasteurized apple juice. A gas chromatography–mass spectroscopy (GC–MS) analysis of lemon grass, thyme, and Mentha virdis essential oils showed their enrichment with monoterpenes class recording 97.10, 97.04, and 97.61%, respectively.

Prevalence of Multidrug-Resistant Diarrheagenic Escherichia coli in Asia: A Systematic Review and Meta-Analysis

Diarrhea is one of the leading causes of morbidity and mortality in developing countries. Diarrheagenic Escherichia coli (DEC) is an important bacterial agent for diarrhea in infants, children, and international travelers, and accounts for more than 30% of diarrheal cases in children less than 5 years old. However, the choices of antimicrobial agents are now being limited by the ineffectiveness of many first-line drugs, in relation to the emergence of antimicrobial-resistant E. coli strains. The aim of this systematic review and meta-analysis was to provide an updated prevalence of antimicrobial-resistant DEC in Asia. A comprehensive systematic search was conducted on three electronic databases (PubMed, ScienceDirect, and Scopus), where 40 eligible studies published between 2010 and 2022 were identified. Using meta-analysis of proportions and a random-effects model, the pooled prevalence of DEC in Asian diarrheal patients was 22.8% (95% CI: 16.5–29.2). The overall prevalence of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing DEC strains was estimated to be 66.3% (95% CI: 58.9–73.7) and 48.6% (95% CI: 35.1–62.1), respectively. Considering antimicrobial drugs for DEC, the resistance prevalence was highest for the penicillin class of antibiotics, where 80.9% of the DEC isolates were resistant to amoxicillin and 73.5% were resistant to ampicillin. In contrast, resistance to carbapenems such as imipenem (0.1%), ertapenem (2.6%), and meropenem (7.9%) was the lowest. The relatively high prevalence estimation signifies that the multidrug-resistant DEC is a public health threat. Effective antibiotic treatment strategies, which may lead to better outcomes for the control of E. coli infections in Asia, are necessary.

Molecular characterization and biofilm-formation analysis of Listeria monocytogenes, Salmonella spp., and Escherichia coli isolated from Brazilian swine slaughterhouses

This study aimed to verify the presence of Listeria monocytogenes, Salmonella spp., and Escherichia coli in two Brazilian swine slaughterhouses, as well as to perform antibiograms, detect virulence and antimicrobial resistance genes, and evaluate the in vitro biofilm-forming capability of bacterial isolates from these environments. One Salmonella Typhi isolate and 21 E. coli isolates were detected, while L. monocytogenes was not detected. S. Typhi was isolated from the carcass cooling chamber’s floor, resistant to several antimicrobials, including nalidixic acid, cefazolin, chloramphenicol, doxycycline, streptomycin, gentamicin, tetracycline, and sulfonamide, and contained resistance genes, such as tet(B), tet(C), tet(M), and ampC. It also showed moderate biofilm-forming capacity at 37°C after incubating for 72 h. The prevalence of the 21 E. coli isolates was also the highest on the carcass cooling chamber floor (three of the four samplings [75%]). The E. coli isolates were resistant to 12 of the 13 tested antimicrobials, and none showed sensitivity to chloramphenicol, an antimicrobial prohibited in animal feed since 2003 in Brazil. The resistance genes MCR-1, MCR-3, sul1, ampC, clmA, cat1, tet(A), tet(B), and blaSHV, as well as the virulence genes stx-1, hlyA, eae, tir α, tir β, tir γ, and saa were detected in the E. coli isolates. Moreover, 5 (23.8%) and 15 (71.4%) E. coli isolates presented strong and moderate biofilm-forming capacity, respectively. In general, the biofilm-forming capacity increased after incubating for 72 h at 10°C. The biofilm-forming capacity was the lowest after incubating for 24 h at 37°C. Due to the presence of resistance and virulence genes, multi-antimicrobial resistance, and biofilm-forming capacity, the results of this study suggest a risk to the public health as these pathogens are associated with foodborne diseases, which emphasizes the hazard of resistance gene propagation in the environment.

Bacteriocin Production by Escherichia coli during Biofilm Development

Escherichia coli is a highly versatile bacterium ranging from commensal to intestinal pathogen, and is an important foodborne pathogen. E. coli species are able to prosper in multispecies biofilms and secrete bacteriocins that are only toxic to species/strains closely related to the producer strain. In this study, 20 distinct E. coli strains were characterized for several properties that confer competitive advantages against closer microorganisms by assessing the biofilm-forming capacity, the production of antimicrobial molecules, and the production of siderophores. Furthermore, primer sets for E. coli bacteriocins–colicins were designed and genes were amplified, allowing us to observe that colicins were widely distributed among the pathogenic E. coli strains. Their production in the planktonic phase or single-species biofilms was uncommon. Only two E. coli strains out of nine biofilm-forming were able to inhibit the growth of other E. coli strains. There is evidence of larger amounts of colicin being produced in the late stages of E. coli biofilm growth. The decrease in bacterial biomass after 12 h of incubation indicates active type I colicin production, whose release normally requires E. coli cell lysis. Almost all E. coli strains were siderophore-producing, which may be related to the resistance to colicin as these two molecules may use the same transporter system. Moreover, E. coli CECT 504 was able to coexist with Salmonella enterica in dual-species biofilms, but Shigella dysenteriae was selectively excluded, correlating with high expression levels of colicin (E, B, and M) genes observed by real-time PCR.

Genomic analysis of plasmid content in food isolates of E. coli strongly supports its role as a reservoir for the horizontal transfer of virulence and antibiotic resistance genes

The link between E. coli strains contaminating foods and human disease is unclear, with some reports supporting a direct transmission of pathogenic strains via food and others highlighting their role as reservoirs for resistance and virulence genes. Here we take a genomics approach, analyzing a large set of fully-assembled genomic sequences from E. coli available in GenBank. Most of the strains isolated in food are more closely related to each other than to clinical strains, arguing against a frequent direct transmission of pathogenic strains from food to the clinic. We also provide strong evidence of genetic exchanges between food and clinical strains that are facilitated by plasmids. This is based on an overlapped representation of virulence and resistance genes in plasmids isolated from these two sources. We identify clusters of phylogenetically-related plasmids that are largely responsible for the observed overlap and see evidence of specialization, with some food plasmid clusters preferentially transferring virulence factors over resistance genes. Consistent with these observations, food plasmids have a high mobilization potential based on their plasmid taxonomic unit classification and on an analysis of mobilization gene content. We report antibiotic resistance genes of high clinical relevance and their specific incompatibility group associations. Finally, we also report a striking enrichment for adhesins in food plasmids and their association with specific IncF replicon subtypes. The identification of food plasmids with specific markers (Inc and PTU combinations) as mediators of horizontal transfer between food and clinical strains opens new research avenues and should assist with the design of surveillance strategies.

Poly-l-lactic acid (PLLA)/anthocyanin nanofiber color indicator film for headspace detection of low-level bacterial concentration

Since bacterial contamination is a significant threat to humans, early detection is essential to safeguard dietary safety and physical health. Here, a nanofiber color indicator film based on poly-l-lactic acid (PLLA) as the support and anthocyanin as the indicator material was prepared by electrostatic spinning. It was found that the PLLA/0.8CY nanofiber color indicator film was hydrophobic (the water contact angle of 102.4°) and contained uniform nanofibers with an average diameter of 750 nm. In addition, the film's humidity insensitivity, reusability, color stability, and ammonia sensitivity (the limits of detection 35.39 ppm) made the film environmentally friendly and more accurate and faster for bacterial detection. The film was able to sense 102 CFU/mL of gram-positive and negative bacteria after the model strain E. coli and L. monocytogene. Thus, the PLLA/0.8CY nanofiber color indicator film was able to perform headspace nondestructive detection of low-level bacterial contamination.

Application of a novel lytic phage vB_EcoM_SQ17 for the biocontrol of Enterohemorrhagic Escherichia coli O157:H7 and Enterotoxigenic E. coli in food matrices

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 and Enterotoxigenic E. coli (ETEC) are important foodborne pathogens, causing serious food poisoning outbreaks worldwide. Bacteriophages, as novel antibacterial agents, have been increasingly exploited to control foodborne pathogens. In this study, a novel broad-host range lytic phage vB_EcoM_SQ17 (SQ17), was isolated, characterized, and evaluated for its potential to control bacterial counts in vitro and in three different food matrices (milk, raw beef, and fresh lettuce). Phage SQ17 was capable of infecting EHEC O157:H7, ETEC, and other E. coli strains. Morphology, one-step growth, and stability assay showed that phage SQ17 belongs to the Caudovirales order, Myoviridae family, and Mosigvirus genus. It has a short latent period of 10 min, a burst size of 71 PFU/infected cell, high stability between pH 4 to 12 as well as thermostability between 30°C and 60°C for 60 min. Genome sequencing analysis revealed that the genome of SQ17 does not contain any genes associated with antibiotic resistance, toxins, lysogeny, or virulence factors, indicating the potential safe application of phage SQ17 in the food industry. In Luria-Bertani (LB) medium, phage SQ17 significantly decreased the viable counts of EHEC O157:H7 by more than 2.40 log CFU/ml (p < 0.05) after 6 h of incubation at 37°C. Phage SQ17 showed great potential to be applied for biocontrol of EHEC O157:H7 in milk and raw beef. In fresh lettuce, treatment with SQ17 also resulted in significant reduction of viable cell counts of EHEC O157:H7 and ETEC at both 4°C and 25°C. Our results demonstrate that SQ17 is a good candidate for application as an EHEC O157:H7 and ETEC biocontrol agent in the processing stages of food production and food preservation.

Modern vaccine development via reverse vaccinology to combat antimicrobial resistance

With the continuous evolution of bacteria, the global antimicrobial resistance health threat is causing millions of deaths yearly. While depending on antibiotics as a primary treatment has its merits, there are no effective alternatives thus far in the pharmaceutical market against some drug-resistant bacteria. In recent years, vaccinology has become a key topic in scientific research. Combining with the growth of technology, vaccine research is seeing a new light where the process is made faster and more efficient. Although less discussed, bacterial vaccine is a feasible strategy to combat antimicrobial resistance. Some vaccines have shown promising results with good efficacy against numerous multidrug-resistant strains of bacteria. In this review, we aim to discuss the findings from studies utilizing reverse vaccinology for vaccine development against some multidrug-resistant bacteria, as well as provide a summary of multi-year bacterial vaccine studies in clinical trials. The advantages of reverse vaccinology in the generation of new bacterial vaccines are also highlighted. Meanwhile, the limitations and future prospects of bacterial vaccine concludes this review.

Temporal Changes in Fecal Unabsorbed Carbohydrates Relative to Perturbations in Gut Microbiome of Neonatal Calves: Emerging of Diarrhea Induced by Extended-Spectrum β-lactamase-Producing Enteroaggregative Escherichia coli

Early gut microbiota development and colonization are crucial for the long-term health and performance of ruminants. However, cognition among these microbiota is still vague, particularly among the neonatal dairy calves. Here, extended-spectrum β-lactamase-producing enteroaggregative E. coli (ESBL-EAEC)-induced temporal changes in diversity, stability, and composition of gut microbiota were investigated among the neonatal female calves, with the view of discerning potential biomarkers of this arising diarrhea cases in local pastures. Nearly, 116 newborn calves were enrolled in this time period study during their first 2 weeks of life, and a total of 40 selected fecal samples from corresponding calves were used in this study. The results revealed that differentiated gut microbiome and metabolome discerned from neonatal calves were accompanied by bacterial infections over time. Commensal organisms like Butyricicoccus, Faecalibacterium, Ruminococcus, Collinsella, and Coriobacterium, as key microbial markers, mainly distinguish “healthy” and “diarrheic” gut microbiome. Random forest machine learning algorithm indicated that enriched fecal carbohydrates, including rhamnose and N-acetyl-D-glucosamine, and abundant short-chain fatty acids (SCFAs) existed in healthy ones. In addition, Spearman correlation results suggested that the presence of Butyricicoccus, Faecalibacterium, Collinsella, and Coriobacterium, key commensal bacteria of healthy calves, is positively related to high production of unabsorbed carbohydrates, SCFAs, and other prebiotics, and negatively correlated to increased concentrations of lactic acid, hippuric acid, and α-linolenic acid. Our data suggested that ESBL-EAEC-induced diarrhea in female calves could be forecasted by alterations in the gut microbiome and markedly changed unabsorbed carbohydrates in feces during early lives, which might be conducive to conduct early interventions to ameliorate clinical symptoms of diarrhea induced by the rising prevalence of ESBL-EAEC.

To kill or to be killed: pangenome analysis of Escherichia coli strains reveals a tailocin specific for pandemic ST131

BACKGROUND

Escherichia coli (E. coli) has been one of the most studied model organisms in the history of life sciences. Initially thought just to be commensal bacteria, E. coli has shown wide phenotypic diversity including pathogenic isolates with great relevance to public health. Though pangenome analysis has been attempted several times, there is no systematic functional characterization of the E. coli subgroups according to the gene profile.

RESULTS

Systematically scanning for optimal parametrization, we have built the E. coli pangenome from 1324 complete genomes. The pangenome size is estimated to be ~25,000 gene families (GFs). Whereas the core genome diminishes as more genomes are added, the softcore genome (≥95% of strains) is stable with ~3000 GFs regardless of the total number of genomes. Apparently, the softcore genome (with a 92% or 95% generation threshold) can define the genome of a bacterial species listing the critically relevant, evolutionarily most conserved or important classes of GFs. Unsupervised clustering of common E. coli sequence types using the presence/absence GF matrix reveals distinct characteristics of E. coli phylogroups B1, B2, and E. We highlight the bi-lineage nature of B1, the variation of the secretion and of the iron acquisition systems in ST11 (E), and the incorporation of a highly conserved prophage into the genome of ST131 (B2). The tail structure of the prophage is evolutionarily related to R2-pyocin (a tailocin) from Pseudomonas aeruginosa PAO1. We hypothesize that this molecular machinery is highly likely to play an important role in protecting its own colonies; thus, contributing towards the rapid rise of pandemic E. coli ST131.

CONCLUSIONS

This study has explored the optimized pangenome development in E. coli. We provide complete GF lists and the pangenome matrix as supplementary data for further studies. We identified biological characteristics of different E. coli subtypes, specifically for phylogroups B1, B2, and E. We found an operon-like genome region coding for a tailocin specific for ST131 strains. The latter is a potential killer weapon providing pandemic E. coli ST131 with an advantage in inter-bacterial competition and, suggestively, explains their dominance as human pathogen among E. coli strains.

Bioinspired fabrication of bifunctional antibody-enzyme co-assembled nanocomposites for chemiluminescence immunoassays of E. coli O157:H7

Immunoassays based on enzyme-labeled antibodies have been widely used in the food safety field. However, the production process of enzyme-labeled antibodies is complicated and the low storage stability limits their application. Herein, antibody-horseradish peroxidase (HRP) co-assembled nanocomposites (AHC NCs) with outstanding advantages such as enhanced stability, lower cost, and substrate affinity were successfully prepared via a one-pot green method. Then the AHC NCs were employed as an alternative to traditional enzyme-labeled antibodies to develop a chemiluminescence enzyme immunoassay (CLEIA) toward Escherichia coli (E. coli) O157:H7. Under optimal conditions, E. coli O157:H7 can be detected in a linear range from 1 × 10³ CFU mL^-1 to 5 × 10⁶ CFU mL^-1, while the limit of detection (LOD) is as low as 2.2 × 10² CFU mL^-1 (3σ). A series of repeatability studies showed reproducible results with a coefficient of variation of less than 7%. In addition, the proposed CLEIA was successfully applied to the analysis of spiked samples (tap water) and gave quantitative recoveries from 93.72% to 100.72%. This work demonstrates that the developed CLEIA can be applied as a universal platform for specific detection of diversified analytes.

Potential of Polyamide Nanofibers With Natamycin, Rosemary Extract, and Green Tea Extract in Active Food Packaging Development: Interactions With Food Pathogens and Assessment of Microbial Risks Elimination

Increasing microbial safety and prolonging the shelf life of products is one of the major challenges in the food industry. Active food packaging made from nanofibrous materials enhanced with antimicrobial substances is considered a promising way. In this study, electrospun polyamide (PA) nanofibrous materials functionalized with 2.0 wt% natamycin (NAT), rosemary extract (RE), and green tea extract (GTE), respectively, were prepared as active packaging and tested for the food pathogens Escherichia coli, Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus. The PAs exhibited: (i) complete retention of bacterial cells reaching 6.0–6.4 log₁₀removal, (ii) antimicrobial activity with 1.6–3.0 log₁₀suppression, and (iii) antibiofilm activity with 1.7–3.0 log₁₀suppression. The PAs prolonged the shelf life of chicken breast; up to 1.9 log₁₀(CFU/g) suppression of total viable colonies and 2.1 log₁₀(CFU/g) suppression of L. monocytogenes were observed after 7 days of storage at 7°C. A beneficial effect on pH and sensory quality was verified. The results confirm microbiological safety and benefits of PA/NAT, PA/RE, and PA/GTE and their potential in developing functional and ecological packaging.

CRISPR/Cas12a-based technology: A powerful tool for biosensing in food safety

BACKGROUND

In the context of the current pandemic caused by the novel coronavirus, molecular detection is not limited to the clinical laboratory, but also faces the challenge of the complex and variable real-time detection fields. A series of novel coronavirus events were detected in the process of food cold chain packaging and transportation, making the application of molecular diagnosis in food processing, packaging, transportation, and other links urgent. There is an urgent need for a rapid detection technology that can adapt to the diversity and complexity of food safety.

SCOPE AND APPROACH

This review introduces a new molecular diagnostic technology-biosensor analysis technology based on CRISPR-Cas12a. Systematic clarification of its development process and detection principles. It summarizes and systematically organizes its applications in viruses, food-borne pathogenic bacteria, small molecule detection, etc. In the past four years, which provides a brand-new and comprehensive solution for food detection. Finally, this article puts forward the challenges and the prospects for food safety.

KEY FINDINGS AND CONCLUSIONS

The novel coronavirus hazards infiltrated every step of the food industry, from processing to packaging to transportation. The biosensor analytical technology based on CRISPR-Cas12a has great potential in the qualitative and quantitative analysis of infectious pathogens. CRISPR-Cas12a can effectively identify the presence of the specific nucleic acid targets and the small changes in sequences, which is particularly important for nucleic acid identification and pathogen detection. In addition, the CRISPR-Cas12a method can be adjusted and reconfigured within days to detect other viruses, providing equipment for nucleic acid diagnostics in the field of food safety. The future work will focus on the development of portable microfluidic devices for multiple detection. Shao et al. employed physical separation methods to separate Cas proteins in different microfluidic channels to achieve multiple detection, and each channel simultaneously detected different targets by adding crRNA with different spacer sequences. Although CRISPR-Cas12a technology has outstanding advantages in detection, there are several technical barriers in the transformation from emerging technologies to practical applications. The newly developed CRISPR-Cas12a-based applications and methods promote the development of numerous diagnostic and detection solutions, and have great potential in medical diagnosis, environmental monitoring, and especially food detection.

Hurdle technology using encapsulated enzymes and essential oils to fight bacterial biofilms

Biofilm formation on abiotic surfaces has become a major public health concern because of the serious problems they can cause in various fields. Biofilm cells are extremely resistant to stressful conditions, because of their complex structure impedes antimicrobial penetration to deep-seated cells. The increased resistance of biofilm to currently applied control strategies underscores the urgent need for new alternative and/or supplemental eradication approaches. The combination of two or more methods, known as Hurdle technology, offers an excellent option for the highly effective control of biofilms. In this perspective, the use of functional enzymes combined with biosourced antimicrobial such as essential oil (EO) is a promising alternative anti-biofilm approach. However, these natural antibiofilm agents can be damaged by severe environmental conditions and lose their activity. The microencapsulation of enzymes and EOs is a promising new technology for enhancing their stability and improving their biological activity. This review article highlights the problems related to biofilm in various fields, and the use of encapsulated enzymes with essential oils as antibiofilm agents. KEY POINTS: • Problems associated with biofilms in the food and medical sectors and their subsequent risks on health and food quality. • Hurdle technology using enzymes and essential oils is a promising strategy for an efficient biofilms control. • The microencapsulation of enzymes and essential oils ensures their stability and improves their biological activities.

Investigation of Antimicrobial and Cytotoxic Properties and Specification of Silver Nanoparticles (AgNPs) Derived From Cicer arietinum L. Green Leaf Extract

Using biological materials to synthesize metallic nanoparticles has become a frequently preferred method by researchers. This synthesis method is both fast and inexpensive. In this study, an aqueous extract obtained from chickpea (Cicer arietinum L.) (CA) leaves was used in order to synthesize silver nanoparticles (AgNPs). For specification of the synthesized AgNPs, UV-vis spectrophotometer, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electron dispersive X-ray (EDX), and zeta potential (ZP) analyses data were used. Biologically synthesized AgNPs demonstrated a maximum surface plasmon resonance of 417.47 nm after 3 h. With the powder XRD model, the mean crystallite dimension of nanoparticles was determined as 12.17 mm with a cubic structure. According to the TEM results, the dimensions of the obtained silver nanoparticles were found to be 6.11–9.66 nm. The ZP of the electric charge on the surface of AgNPs was measured as −19.6 mV. The inhibition effect of AgNPs on food pathogen strains and yeast was determined with the minimum inhibition concentration (MIC) method. AgNPs demonstrated highly effective inhibition at low concentrations especially against the growth of B. subtilis (0.0625) and S. aureus (0.125) strains. The cytotoxic effects of silver nanoparticles on cancerous cell lines (CaCo-2, U118, Sk-ov-3) and healthy cell lines (HDF) were revealed. Despite the increase of AgNPs used against cancerous and healthy cell lines, no significant decrease in the percentage of viability was detected.

In silico Designing of an Epitope-Based Vaccine Against Common E. coli Pathotypes

Escherichia coli (E. coli) is a Gram-negative bacterium that belongs to the family Enterobacteriaceae. While E. coli can stay as an innocuous resident in the digestive tract, it can cause a group of symptoms ranging from diarrhea to live threatening complications. Due to the increased rate of antibiotic resistance worldwide, the development of an effective vaccine against E. coli pathotypes is a major health priority. In this study, a reverse vaccinology approach along with immunoinformatics has been applied for the detection of potential antigens to develop an effective vaccine. Based on our screening of 5,155 proteins, we identified lipopolysaccharide assembly protein (LptD) and outer membrane protein assembly factor (BamA) as vaccine candidates for the current study. The conservancy of these proteins in the main E. coli pathotypes was assessed through BLASTp to make sure that the designed vaccine will be protective against major E. coli pathotypes. The multitope vaccine was constructed using cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and B cell lymphocyte (BCL) epitopes with suitable linkers and adjuvant. Following that, it was analyzed computationally where it was found to be antigenic, soluble, stable, and non-allergen. Additionally, the adopted docking study, as well as all-atom molecular dynamics simulation, illustrated the promising predicted affinity and free binding energy of this constructed vaccine against the human Toll-like receptor-4 (hTLR-4) dimeric state. In this regard, wet lab studies are required to prove the efficacy of the potential vaccine construct that demonstrated promising results through computational validation.

Quantitative Imaging of Bacteriophage Amplification for Rapid Detection of Bacteria in Model Foods

Rapid detection of bacteria in water and food samples is a critical need. The current molecular methods like real-time PCR can provide rapid detection after initial enrichment. However, these methods require significant preparation steps, specialized facilities to reduce contamination, and relatively expensive reagents. This study evaluates a novel approach for detecting bacteria based on imaging of bacteriophage amplification upon infection of the target host bacteria to mitigate some of these constraints and improve the specificity of discriminating live vs. dead bacteria. Thus, this research leverages the natural ability of lytic bacteriophages to rapidly amplify their genetic material and generate progeny phages upon infecting the host bacterium. This study uses a nucleic acid staining dye, a conventional fluorescence microscope, and quantitative image analysis for imaging the amplification of bacteriophages. The sensitivity and assay time for imaging-based quantification of phage amplification for detecting Escherichia coli were compared with RT-PCR and the standard plaque-forming assay for detection phage amplification in model systems, including coconut water and spinach wash water. The results demonstrate that the imaging approach matches both the sensitivity and speed for detecting E. coli using the RT-PCR method without requiring isolation of nucleic acids, expensive reagents, and specialized facilities. The quantitative imaging results demonstrate the detection of 10 CFU/ml of E. coli in coconut water and simulated spinach wash water with a chemical oxygen demand (COD) of 3,000 ppm within 8 h, including initial enrichment of the bacteria. In summary, the results of this study illustrate a novel phage amplification-based approach for detecting target bacteria in complex food and water samples using simple sample preparation methods and low-cost reagents.

Pretreatment with Allura Red or Tartrazine Increase Resistance of E. coli and Staphylococcus aureus to some Preservatives

Coloring agents such as allura red and tartrazine are frequently used in food and pharmaceutical industries. Also, many types of preservatives are added to food and pharmaceutical products to prevent their spoilage. This study examined the effect of pretreatment with nutrient broth containing allura red (AR) or tartrazine (TA) on survival of E. coli and Staphylococcus aureus in media containing preservatives (eg ascorbic acid, citric acid, or sodium chloride). Pretreatment of E. coli for 4 days with AR or TA before exposure for 3 days to nutrient broth containing NaCl (20%) significantly increased its resistance to sodium chloride (20%). Pretreatment of E. coli for 4 days with AR, TA, or nutrient broth alone before exposure for 3 days to nutrient broth containing ascorbic acid (1%) or to nutrient broth containing citric acid (0.5%) killed all cells. For S. aureus, pretreatment with AR or TA before exposure for 3 days to nutrient broth containing citric acid (0.3%) significantly increased its resistance to citric acid (0.3%). Pretreatment of S. aureus for 4 days with AR, TA, or nutrient broth alone before exposure for 3 days to nutrient broth containing citric acid (0.3%) reduced number of cells by 4.37, 2.54, and 6.97 logs, respectively. Pretreatment of S. aureus for 4 days with AR, TA, or nutrient broth alone before exposure for 3 days to nutrient broth containing ascorbic acid (0.5%) reduced number of viable cells by 3, 3.6, and 3.07 logs, respectively. Pretreatment of S. aureus for 4 days with AR, TA, or nutrient broth alone before exposure for 3 days to nutrient broth containing NaCl (20%) increased number of cells by 0.74, 0.7 and 1.1logs, respectively. These results have implications in food and pharmaceutical industries.

Escherichia coli O103 outbreak associated with minced celery among hospitalized individuals in Victoria, British Columbia, 2021

BACKGROUND

In April 2021, a Shiga toxin-producing Escherichia coli (E. coli) (STEC) O103 outbreak was identified among patients at two hospitals in Victoria, British Columbia (BC). The objective of this study is to describe this outbreak investigation and identify issues of food safety for high-risk products prepared for vulnerable populations.

METHODS

Confirmed cases of E. coli O103 were reported to the Island Health communicable disease unit. The provincial public health laboratory conducted whole genome sequencing on confirmed case isolates, as per routine practice for STEC in BC. Exposure information was obtained through case interviews and review of hospital menus. Federal and local public health authorities conducted an inspection of the processing plant for the suspect source.

RESULTS

Six confirmed cases of E. coli O103 were identified, all related by whole genome sequencing. The majority of cases were female (67%) and the median age was 61 years (range 24-87 years). All confirmed cases were inpatients or outpatients at two hospitals and were exposed to raw minced celery within prepared sandwiches provided by hospital food services. A local processor supplied the minced celery exclusively to the two hospitals. Testing of product at the processor was infrequent, and chlorine rinse occurred before mincing. The spread of residual E. coli contamination through the mincing process, in addition to temperature abuse at the hospitals, are thought to have contributed to this outbreak.

CONCLUSION

Raw vegetables, such as celery, are a potential source of STEC and present a risk to vulnerable populations. Recommendations from this outbreak include more frequent testing at the processor, a review of the chlorination and mincing process and a review of hospital food services practices to mitigate temperature abuse.

Ultrasonic-assisted preparation of eucalyptus oil nanoemulsion: Process optimization, in vitro digestive stability, and anti-Escherichia coli activity

Eucalyptus oil (EO) is a natural and effective antimicrobial agent; however, it has disadvantages such as poor water solubility and instability. The aim of this study was to investigate the effect of process vessels and preparation process parameters on the particle size of the emulsion droplets using ultrasonic technique and response surface methodology to prepare eucalyptus oil nanoemulsion (EONE). The optimal sonication process parameters in conical centrifuge tubes were confirmed: sonication distance of 0.9 cm, sonication amplitude of 18%, and sonication time of 2 min. Under these conditions, the particle size of EONE was 18.96 ± 4.66 nm, the polydispersity index was 0.39 ± 0.09, and the zeta potential was -31.17 ± 2.15 mV. In addition, the changes in particle size, potential, micromorphology, and anti-Escherichia coli activity of EONE during digestion were investigated by in vitro simulated digestion. The emulsion was stable in simulated salivary fluid, tended to aggregate in simulated gastric fluid, and increased in particle size and potential value in simulated intestinal fluid. EONE showed higher anti-E. coli activity than EO by simulated digestion. These results provide a useful reference for the in vivo antimicrobial application of the essential oil.

Zinc Polyaleuritate Ionomer Coatings as a Sustainable, Alternative Technology for Bisphenol A-Free Metal Packaging

Sustainable coatings for metal food packaging were prepared from ZnO nanoparticles (obtained by the thermal decomposition of zinc acetate) and a naturally occurring polyhydroxylated fatty acid named aleuritic (or 9,10,16-trihydroxyhexadecanoic) acid. Both components reacted, originating under specific conditions zinc polyaleuritate ionomers. The polymerization of aleuritic acid into polyaleuritate by a solvent-free, melt polycondensation reaction was investigated at different times (15, 30, 45, and 60 min), temperatures (140, 160, 180, and 200 °C), and proportions of zinc oxide and aleuritic acid (0:100, 5:95, 10:90, and 50:50, w/w). Kinetic rate constants calculated by infrared spectroscopy decreased with the amount of Zn due to the consumption of reactive carboxyl groups, while the activation energy of the polymerization decreased as a consequence of the catalyst effect of the metal. The adhesion and hardness of coatings were determined from scratch tests, obtaining values similar to robust polymers with high adherence. Water contact angles were typical of hydrophobic materials with values ≥94°. Both mechanical properties and wettability were better than those of bisphenol A (BPA)-based resins and most likely are related to the low migration values determined using a hydrophilic food simulant. The presence of zinc provided a certain degree of antibacterial properties. The performance of the coatings against corrosion was studied by electrochemical impedance spectroscopy at different immersion times in an aqueous solution of NaCl. Considering the features of these biobased lacquers, they can be potential materials for bisphenol A-free metal packaging.

Development and Effective Utilization of a Rapid Multiplex Real-Time PCR of Diarrheagenic Escherichia coli for Food Poisoning Cases

Diarrheagenic Escherichia coli (DEC) causes diarrheal symptoms in humans. The comprehensive detection of DEC from feces using SYBR Green real-time PCR assay requires multiple runs. Moreover, PCR screening can have discrepancies related to the conformance between the results from PCR screening and culturing. We aimed to develop a real-time PCR for the comprehensive testing of DEC for diagnostic support that can be used in any general laboratory and proposed its effective utilization. We tested specificity for the designed primer sets using 100 strains. Moreover, screening and isolation of DEC were performed using the proposed multiplex real-time PCR system for 308 fecal samples collected from 37 food poisoning incidences that occurred in Gifu Prefecture, Japan from 2017 to 2019. Furthermore, the factor of discrepant results between PCR screening and culturing was analyzed by quantifying the number of DEC cell and whole E. coli cell using real-time PCR for 47 PCR screening-positive fecal samples. The results obtained from the developed multiplex real-time PCR system were in 99% concordance with those from the conventional techniques. A total of 49 fecal samples were detected with virulence genes for the screening. Of the samples which were positive with virulence genes by PCR screening, 38.3% could not be detected from the strain for bacterial culture. We found that the culturing positive samples were significantly high in numbers for the DEC cells, but no significant difference was noted in the whole E. coli cells with culturing negative samples. The multiplex real-time PCR developed in this study was found to be rapid and practical for DEC testing. The PCR screening for DEC using this method can provide rapid information toward the diagnostic support of DEC infection.

Genomic analysis of shiga toxin-containing Escherichia coli O157:H7 isolated from Argentinean cattle

Cattle are the main reservoir of Enterohemorrhagic Escherichia coli (EHEC), with O157:H7 the distinctive serotype. EHEC is the main causative agent of a severe systemic disease, Hemolytic Uremic Syndrome (HUS). Argentina has the highest pediatric HUS incidence worldwide with 12–14 cases per 100,000 children. Herein, we assessed the genomes of EHEC O157:H7 isolates recovered from cattle in the humid Pampas of Argentina. According to phylogenetic studies, EHEC O157 can be divided into clades. Clade 8 strains that were classified as hypervirulent. Most of the strains of this clade have a Shiga toxin stx2a-stx2c genotype. To better understand the molecular bases related to virulence, pathogenicity and evolution of EHEC O157:H7, we performed a comparative genomic analysis of these isolates through whole genome sequencing. The isolates classified as clade 8 (four strains) and clade 6 (four strains) contained 13 to 16 lambdoid prophages per genome, and the observed variability of prophages was analysed. An inter strain comparison show that while some prophages are highly related and can be grouped into families, other are unique. Prophages encoding for stx2a were highly diverse, while those encoding for stx2c were conserved. A cluster of genes exclusively found in clade 8 contained 13 genes that mostly encoded for DNA binding proteins. In the studied strains, polymorphisms in Q antiterminator, the Q-stx2A intergenic region and the O and P γ alleles of prophage replication proteins are associated with different levels of Stx2a production. As expected, all strains had the pO157 plasmid that was highly conserved, although one strain displayed a transposon interruption in the protease EspP gene. This genomic analysis may contribute to the understanding of the genetic basis of the hypervirulence of EHEC O157:H7 strains circulating in Argentine cattle. This work aligns with other studies of O157 strain variation in other populations that shows key differences in Stx2a-encoding prophages.

Surveillance and Reduction Control of Escherichia coli and Diarrheagenic E. coli During the Pig Slaughtering Process in China

The microbial contamination of pork during the slaughter process, especially that of the hygiene indicator bacteria, Escherichia coli, is closely related to the safety and quality of the meat. Some diarrheagenic E. coli can cause serious foodborne diseases, and pose a significant threat to human life and health. In order to ascertain the current status of E. coli and diarrheagenic E. coli contamination during the pig slaughter process in China, we conducted thorough monitoring of large-sized slaughterhouses, as well as small- or medium-sized slaughterhouses, in different provinces of China from 2019 to 2020. The overall positive rate of E. coli on the pork surface after slaughter was very high (97.07%). Both the amount of E. coli contamination and the positive ratio of diarrheagenic E. coli in large-sized slaughterhouses (7.50–13.33 CFU/cm², 3.44%) were lower than those in small- or medium-sized slaughterhouses (74.99–133.35 CFU/cm², 5.71%). Combined with the current status of sanitary control in slaughterhouses, we determined that pre-cooling treatment significantly reduced E. coli and diarrheagenic E. coli in pork after slaughter, while microbiological testing reduced E. coli. Based on our monitoring data, China urgently needs to establish relevant standards to better control microbial contamination during pig slaughtering progress. This study provided a theoretical basis for the hygiene quality management of the pig slaughter industry in China.

A Galactosidase-Activatable Fluorescent Probe for Detection of Bacteria Based on BODIPY

Pathogenic E. coli infection is one of the most widespread foodborne diseases, so the development of sensitive, reliable and easy operating detection tests is a key issue for food safety. Identifying bacteria with a fluorescent medium is more sensitive and faster than using chromogenic media. This study designed and synthesized a β-galactosidase-activatable fluorescent probe BOD-Gal for the sensitive detection of E. coli. It employed a biocompatible and photostable 4,4-difluoro-3a,4a-diaza-s-indancene (BODIPY) as the fluorophore to form a β-O-glycosidic bond with galactose, allowing the BOD-Gal to show significant on-off fluorescent signals for in vitro and in vivo bacterial detection. This work shows the potential for the use of a BODIPY based enzyme substrate for pathogen detection.

Antimicrobial Effect of Tea Polyphenols against Foodborne Pathogens: A Review

ABSTRACT

Food contamination by foodborne pathogens is still widespread in many countries around the world, and food safety is a major global public health issue. Therefore, novel preservatives that can guarantee safer food are in high demand. Contrary to artificial food preservatives, tea polyphenols (TPs) are getting wide attention as food additives for being "green," "safe," and "healthy." TPs come from many sources, and the purification technology is sophisticated. Compared with other natural antibacterial agents, the antibacterial effect of TPs is more stable, making them excellent natural antibacterial agents. This review includes a systematic summary of the important chemical components of TPs and the antibacterial mechanisms of TPs against various foodborne pathogens. The potential applications of TPs are also discussed. These data provide a theoretical basis for the in-depth study of TPs.

HIGHLIGHTS

Pyrolysis of cajuput (Melaleuca leucadendron) twigs and rice (Oryza sativa) husks to produce liquid smoke-containing fine chemicals for antibacterial agent application

Pyrolysis of cajuput (Melaleuca leucadendron) twigs and rice (Oryza sativa) husks to produce liquid smoke and antibacterial activities of the liquid smoke fractions were investigated. The liquid smoke was produced by pyrolysis at 500 °C for 8 h and contained fine chemicals, such as acetic acid, carbonyl, cyclic ketones, and phenolic compounds with pH 2.1-2.9. The liquid smoke was separated by vacuum evaporation under vacuum conditions at low temperatures (40 °C, 50 °C, and 60 °C) to recover three fractions. The composition of each fraction influenced its antibacterial activities. Antibacterial activities of the liquid smoke fractions were tested against Gram-positive bacteria (Listeria monocytogenes, Bacillus subtilis, and Staphylococcus aureus) and Gram-negative bacteria (Salmonella typhimurium, Pseudomonas aeruginosa, and Escherichia coli). Whole fractions of the liquid smoke inhibited the six pathogenic bacteria, with the inhibition zone larger or smaller than the positive control. Among the liquid smoke fractions, the liquid recovered at 60 °C for the cajuput twigs and rice husks demonstrated a stronger inhibitory effect on bacterial growth than the other fractions.

Virulence Factors of Enteric Pathogenic Escherichia coli: A Review

Escherichia coli are remarkably versatile microorganisms and important members of the normal intestinal microbiota of humans and animals. This harmless commensal organism can acquire a mixture of comprehensive mobile genetic elements that contain genes encoding virulence factors, becoming an emerging human pathogen capable of causing a broad spectrum of intestinal and extraintestinal diseases. Nine definite enteric E. coli pathotypes have been well characterized, causing diseases ranging from various gastrointestinal disorders to urinary tract infections. These pathotypes employ many virulence factors and effectors subverting the functions of host cells to mediate their virulence and pathogenesis. This review summarizes new developments in our understanding of diverse virulence factors associated with encoding genes used by different pathotypes of enteric pathogenic E. coli to cause intestinal and extraintestinal diseases in humans.

Implementation of Food Safety Management Systems along with Other Management Tools (HAZOP, FMEA, Ishikawa, Pareto). The Case Study of Listeria monocytogenes and Correlation with Microbiological Criteria

The food industry’s failure in planning and designing of and in implementing a Food Safety Management System and its foundation elements leads, in most instances, to compromised food safety and subsequent foodborne illness outbreaks. This phenomenon was noticed, worldwide, for all food processors, but with a much higher incidence in the medium- and small-sized food processing plants. Our study focuses on the importance of Food Safety Management System (FSMS), Critical Control Points Hazard Analysis (HACCP) and the Prerequisite Programs (PRPs) as the foundation of HACCP, in preventing foodborne outbreaks. For emphasis, we make use of the example of organizational food safety culture failures and the lack of managerial engagement which resulted in a multi-state listeriosis outbreak in USA. Moreover, we correlate this with microbiological criteria. Implementation of food safety management systems (ISO 22000:2018) along with incorporation of management tools such as HAZOP, FMEA, Ishikawa and Pareto have proved to be proactive in the maintenance of a positive food safety culture and prevention of cross-contamination and fraud.