Emerging trends in foodborne diseases

Nanobody-Based Immunoassays for the Detection of Food Hazards-A Review

Food safety remains a significant global challenge that affects human health. Various hazards, including microbiological and chemical threats, can compromise food safety throughout the supply chain. To address food safety issues and ensure public health, it is necessary to adopt rapid, accurate, and highly specific detection methods. Immunoassays are considered to be an effective method for the detection of highly sensitive biochemical indicators and provide an efficient platform for the identification of food hazards. In immunoassays, antibodies function as the primary recognition elements. Nanobodies have significant potential as valuable biomolecules in diagnostic applications. Their distinctive physicochemical and structural characteristics make them excellent candidates for the development of reliable diagnostic assays, and as promising alternatives to monoclonal and polyclonal antibodies. Herein, we summarize a comprehensive overview of the status and prospects of nanobody-based immunoassays in ensuring food safety. First, we begin with a historical perspective on the development of nanobodies and their unique characteristics. Subsequently, we explore the definitions and boundaries of immunoassays and immunosensors, before discussing the potential applications of nanobody-based immunoassays in food safety testing that have emerged over the past five years, and follow the different immunoassays, highlighting their advantages over traditional detection methods. Finally, the directions and challenges of nanobody-based immunoassays in food safety are discussed. Due to their remarkable sensitivity, specificity and versatility, nanobody-based immunoassays hold great promise in revolutionizing food safety testing and ensuring public health and well-being.

Thyme Essential Oil as a Potential Tool Against Common and Re-Emerging Foodborne Pathogens: Biocidal Effect on Bacterial Membrane Permeability

Over the past decade, foodborne diseases have become a significant public health concern, affecting millions of people globally. Major pathogens like Salmonella spp., Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus contaminate food and cause several infections. This study investigates the potential of thyme essential oil (Thy-EO) as a natural antimicrobial agent against most common and re-emerging foodborne bacteria, including S. enterica, Yersinia enterocolitica, and L. monocytogenes. Preliminary tests provided qualitative evidence of Thy-EO's efficacy by evaluating its antibacterial activity through direct contact and vapor phase exposure. Then, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were defined to quantitatively evaluate the bacteriostatic and bactericidal effects of Thy-EO, revealing a strong inhibitory effect against S. enterica, Y. enterocolitica and L. monocytogenes. Additionally, Thy-EO exerted rapid bactericidal kinetics characterized by the disruption of bacterial cell membrane integrity over time. Results highlight Thy-EO's potential as an alternative antimicrobial agent, demonstrating that treatment with Thy-EO significantly and irreversibly affects the growth of the tested foodborne pathogens.

Application of DNA-fueled molecular machines in food safety testing

Food is consumed by humans, which is indispensable to human life. Therefore, considerable attention of the whole society has been paid to food safety. Over the last few years, dramatic social development has brought new challenges to food safety, making developing new and quick methods for on-site food safety testing an important necessity. As a result, DNA-fueled molecular machines, characterized by high efficiency, accuracy, and sensitivity in testing, have come into the spotlight, based on which sensors can be constructed to detect toxic and harmful substances in food products. This study reviewed recent research on several DNA-fueled molecular machines, including DNA tweezers, DNA walkers, and DNA origami, for rapidly detecting toxic and harmful substances. Based on the above studies, the sensitivity and timeliness of several DNA molecular machines were summarized and compared, and the development prospect of DNA fuel molecular machines in the field of food safety detection was prospected.

Possible Beneficial Effects of Hydrolyzable Tannins Deriving from Castanea sativa L. in Internal Medicine

Hydrolyzable tannins (HTs) deriving from chestnuts have demonstrated, through numerous studies, the ability to exert multiple beneficial effects, including antioxidant and antimicrobial effects, on the lipid metabolism and cancer cells. The latter effect is very fascinating, since different polyphenols deriving from chestnuts were able to synergistically induce the inhibition of cancerous cells through multiple pathways. Moreover, the main mechanisms by which tannins induce antioxidant functions include: the reduction in oxidative stress, the ability to scavenge free radicals, and the modulation of specific enzymes, such as superoxide dismutase. HTs have also been shown to exert significant antimicrobial activity by suppressing microbial growth. The actions on the lipid metabolism are several, among which is the inhibition of lipid accumulation. Thus, tannins seem to induce a cardioprotective effect. In fact, through various mechanisms, such as the relaxation of the vascular smooth muscle, HTs were proven to be efficient against arterial hypertension. Therefore, the great number of studies in this field prove the growing interest on the utilization of natural bioactive compounds, such as HTs deriving from natural sources or obtained by circular economy models, as potential nutraceuticals or adjuvants therapies.

Escherichia albertii as a Potential Enteropathogen in the Light of Epidemiological and Genomic Studies

Escherichia albertii is a new enteropathogen of humans and animals. The aim of the study was to assess the prevalence and pathogenicity of E. albertii strains isolated in northeastern Poland using epidemiological and genomic studies. In 2015-2018, a total of 1154 fecal samples from children and adults, 497 bird droppings, 212 food samples, 92 water samples, and 500 lactose-negative E. coli strains were tested. A total of 42 E. albertii strains were isolated. The PCR method was suitable for their rapid identification. In total, 33.3% of E. albertii isolates were resistant to one antibiotic, and 16.7% to two. Isolates were sensitive to cefepime, imipenem, levofloxacin, gentamicin, trimethoprim/sulfamethoxazole, and did not produce ESBL β-lactamases. High genetic variability of E. albertii has been demonstrated. In the PFGE method, 90.5% of the strains had distinct pulsotypes. In MLST typing, 85.7% of strains were assigned distinct sequence types (STs), of which 64% were novel ST types. Cytolethal distending toxin (CDT) and Paa toxin genes were found in 100% of E. albertii isolates. Genes encoding toxins, IbeA, CdtB type 2, Tsh and Shiga (Stx2f), were found in 26.2%, 9.7%, 1.7%, and 0.4% of E. albertii isolates, respectively. The chromosome size of the tested strains ranged from 4,573,338 to 5,141,010 bp (average 4,784,003 bp), and at least one plasmid was present in all strains. The study contributes to a more accurate assessment of the genetic diversity of E. albertii and the potential threat it poses to public health.

A quantitative prevalence of Escherichia coliO157 in different food samples using real-time qPCR method

Escherichia coli serogroup O157 is the main causative agent of several intestinal and extra-intestinal foodborne diseases in humans through consumption of low-dose contaminated foods such as milk, beef, and vegetables. To date, studies regarding the quantitative prevalence of E. coli O157 in foods are so limited. Therefore, this study aimed to evaluate the quantitative prevalence rate of E. coli serogroup O157 in raw milk (n = 144), vegetable salad (n = 174), and minced beef samples (n = 108) using the real-time qPCR SYBR green melting curve method targeting the rfbA gene. First, we evaluated the method and found a sensitive and specific qPCR assay with 1 log of CFU/ml detection limit to detect E. coli O157 (Tm = 80.3 ± 0.1°C). About 2.77%, 10.18%, and 9.19% of raw milk, minced beef, and vegetable salad samples, respectively, were contaminated with E. coli O157. Minced beef and vegetable salad samples were significantly more contaminated than raw milk samples. Population average of E. coli O157 in raw milk, minced beef, and vegetable salad samples were 2.22 ± 0.57, 3.30 ± 0.40, and 1.65 ± 0.44 log CFU/ml or gr, respectively. Significantly higher levels of population of E. coli O157 were observed in minced beef samples. Minced beef can be regarded as the main food in the transmission of this foodborne pathogen. Routine quantitative rapid monitoring is strongly suggested to be carried out to prevent foodborne diseases caused by E. coli O157.

Application of Nanopore Sequencing in the Detection of Foodborne Microorganisms

Foodborne pathogens have become the subject of intense interest because of their high incidence and mortality worldwide. In the past few decades, people have developed many methods to solve this challenge. At present, methods such as traditional microbial culture methods, nucleic acid or protein-based pathogen detection methods, and whole-genome analysis are widely used in the detection of pathogenic microorganisms in food. However, these methods are limited by time-consuming, cumbersome operations or high costs. The development of nanopore sequencing technology offers the possibility to address these shortcomings. Nanopore sequencing, a third-generation technology, has the advantages of simple operation, high sensitivity, real-time sequencing, and low turnaround time. It can be widely used in the rapid detection and serotyping of foodborne pathogens. This review article discusses foodborne diseases, the principle of nanopore sequencing technology, the application of nanopore sequencing technology in foodborne pathogens detection, as well as its development prospects.

Low-energy electron beam has severe impact on seedling development compared to cold atmospheric pressure plasma

Sprouts are germinated seeds that are often consumed due to their high nutritional content and health benefits. However, the conditions for germination strongly support the proliferation of present bacteria, including foodborne pathogens. Since sprouts are consumed raw or minimally processed, they are frequently linked to cases of food poisoning. Therefore, a seed decontamination method that provides efficient inactivation of microbial pathogens, while maintaining the germination capacity and quality of the seeds is in high demand. This study aimed to investigate and compare seed decontamination by cold atmospheric-pressure plasma and low-energy electron beam with respect to their impact on seed and seedling quality. The results show that both technologies provide great potential for inactivation of microorganisms on seeds, while cold plasma yielded a higher efficiency with 5 log units compared to a maximum of 3 log units after electron beam treatment. Both techniques accelerated seed germination, defined by the percentage of hypocotyl and leaf emergence at 3 days, with short plasma treatment (< 120 s) and all applied doses of electron beam treatment (8-60 kGy). However, even the lowest dose of electron beam treatment at 8 kGy in this study caused root abnormalities in seedlings, suggesting a detrimental effect on the seed tissue. Seeds treated with cold plasma had an eroded seed coat and increased seed wettability compared to electron beam treated seeds. However, these effects cannot explain the increase in the germination capacity of seeds as this was observed for both techniques. Future studies should focus on the investigation of the mechanisms causing accelerated seed germination and root abnormalities by characterizing the molecular and physiological impact of cold plasma and electron beam on seed tissue.

AFM-Based Correlative Microscopy Illuminates Human Pathogens

Microbes have an arsenal of virulence factors that contribute to their pathogenicity. A number of challenges remain to fully understand disease transmission, fitness landscape, antimicrobial resistance and host heterogeneity. A variety of tools have been used to address diverse aspects of pathogenicity, from molecular host-pathogen interactions to the mechanisms of disease acquisition and transmission. Current gaps in our knowledge include a more direct understanding of host-pathogen interactions, including signaling at interfaces, and direct phenotypic confirmation of pathogenicity. Correlative microscopy has been gaining traction to address the many challenges currently faced in biomedicine, in particular the combination of optical and atomic force microscopy (AFM). AFM, generates high-resolution surface topographical images, and quantifies mechanical properties at the pN scale under physiologically relevant conditions. When combined with optical microscopy, AFM probes pathogen surfaces and their physical and molecular interaction with host cells, while the various modes of optical microscopy view internal cellular responses of the pathogen and host. Here we review the most recent advances in our understanding of pathogens, recent applications of AFM to the field, how correlative AFM-optical microspectroscopy and microscopy have been used to illuminate pathogenicity and how these methods can reach their full potential for studying host-pathogen interactions.

Cockroaches and Food-borne Pathogens

Food-borne disease is a widespread and escalating public health problem globally. About a quarter of the microorganisms isolated from cockroaches are food-borne pathogens including Escherichia coli O157:H7, Staphylococcus aureus, Bacillus cereus, Shigella dysenteriae, Salmonella enterica subsp. enterica serovar Typhi, Rotavirus, Aspergillus fumigatus, and Cryptosporidium parvum. Thus, cockroaches could be an important reservoir and mechanical vector of food-borne pathogens. Generally, the role of cockroaches in human infections is poorly understood and has been an issue of debate for several years. This article aims to elucidate the possible role of cockroaches in food-borne infections by reviewing the relevant research publications.

Cognitive Biases of Consumers' Risk Perception of Foodborne Diseases in China: Examining Anchoring Effect

Consumer cognitive biases arise from judgment and decision-making due to their limitations in information processing. As one of the important cognitive biases, the anchoring effect plays a significant role in interfering with consumers’ risk perception. With a stratified random approach, we collected survey data from 375 consumers in Wuxi, Jiangsu Province, China. Based on these data, this study attempted to analyze the anchoring effect in consumers’ risk perception of foodborne diseases (FBDs) and the differences in their perception before and after intervention in a contrast experiment using the anchoring index and the Wilcoxon signed-rank test. The results confirm the existence of the proposed anchoring effect. Moreover, the experimenter-provided anchor value, a history of FBD, and familiarity with FBD were found to be important factors influencing this anchoring effect. Therefore, improving consumers’ risk perception of FBD is critical to the long-term prevention of FBD risks by the government and consumers. The government should strengthen active monitoring, publicity, and education about FBD.

A Comparative Study on the Effects of Quinic Acid and Shikimic Acid on Cellular Functions of Staphylococcus aureus

Quinic acid (QA) and shikimic acid (SA), two kinds of natural organic acids, have been reported to exhibit potent antibacterial activity against Staphylococcus aureus. In this study, the effects of QA and SA on the cellular functions of S. aureus were investigated by measuring the intracellular pH, intracellular and extracellular ATP concentrations, succinate dehydrogenase activity, DNA content, and interactions between SA and QA with S. aureus DNA. Studies of the cellular functions demonstrated that QA could significantly decrease the intracellular pH, whereas SA had no effect on intracellular pH. QA and SA reduced succinate dehydrogenase activity and caused a significant decrease in intracellular ATP concentration but no proportional increase in extracellular ATP. Moreover, QA and SA both could remarkably reduce the DNA content of S. aureus and directly interact with genomic DNA. The results suggested that the effects of QA and SA on cellular functions were distinguishable, although the chemical structures of these two compounds were similar. In conclusion, the results of the present research suggested that SA and QA could be used as antibacterial agents in food preservation.

An Updated Scheme for Categorizing Foods Implicated in Foodborne Disease Outbreaks: A Tri-Agency Collaboration

BACKGROUND

Foodborne disease data collected during outbreak investigations are used to estimate the percentage of foodborne illnesses attributable to specific food categories. Current food categories do not reflect whether or how the food has been processed and exclude many multiple-ingredient foods.

MATERIALS AND METHODS

Representatives from three federal agencies worked collaboratively in the Interagency Food Safety Analytics Collaboration (IFSAC) to develop a hierarchical scheme for categorizing foods implicated in outbreaks, which accounts for the type of processing and provides more specific food categories for regulatory purposes. IFSAC also developed standard assumptions for assigning foods to specific food categories, including some multiple-ingredient foods. The number and percentage of outbreaks assignable to each level of the hierarchy were summarized.

RESULTS

The IFSAC scheme is a five-level hierarchy for categorizing implicated foods with increasingly specific subcategories at each level, resulting in a total of 234 food categories. Subcategories allow distinguishing features of implicated foods to be reported, such as pasteurized versus unpasteurized fluid milk, shell eggs versus liquid egg products, ready-to-eat versus raw meats, and five different varieties of fruit categories. Twenty-four aggregate food categories contained a sufficient number of outbreaks for source attribution analyses. Among 9791 outbreaks reported from 1998 to 2014 with an identified food vehicle, 4607 (47%) were assignable to food categories using this scheme. Among these, 4218 (92%) were assigned to one of the 24 aggregate food categories, and 840 (18%) were assigned to the most specific category possible.

CONCLUSIONS

Updates to the food categorization scheme and new methods for assigning implicated foods to specific food categories can help increase the number of outbreaks attributed to a single food category. The increased specificity of food categories in this scheme may help improve source attribution analyses, eventually leading to improved foodborne illness source attribution estimates and enhanced food safety and regulatory efforts.

The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review

In some animals, the typical body temperature can be higher than humans, for example, 42°C in poultry and 40°C in rabbits which can be a potential thermal stress challenge for pathogens. Even in animals with lower body temperatures, when infection occurs, the immune system may increase body temperature to reduce the chance of survival for pathogens. However, some pathogens can still easily overcome higher body temperatures and/or rise in body temperatures through expression of stress response mechanisms. Salmonella is the causative agent of one of the most prevalent foodborne illnesses, salmonellosis, and can readily survive over a wide range of temperatures due to the efficient expression of the heat (thermal) stress response. Therefore, thermal resistance mechanisms can provide cross protection against other stresses including the non-specific host defenses found within the human body thus increasing pathogenic potential. Understanding the molecular mechanisms associated with thermal responses in Salmonella is crucial in designing and developing more effective or new treatments for reducing and eliminating infection caused by Salmonella that have survived heat stress. In this review, Salmonella thermal resistance is assessed followed by an overview of the thermal stress responses with a focus on gene regulation by sigma factors, heat shock proteins, along with the corresponding thermosensors and their association with virulence expression including a focus on a potential link between heat resistance and potential for infection.

A review on microbiological decontamination of fresh produce with nonthermal plasma

Food safety is a critical public health issue for consumers and the food industry because microbiological contamination of food causes considerable social and economic burdens on health care. Most foodborne illness comes from animal production, but as of the mid-1990s in the United States and more recently in the European Union, the contribution of fresh produce to foodborne outbreaks has rapidly increased. Recent studies have suggested that sterilization with nonthermal plasma could be a viable alternative to the traditional methods for the decontamination of heat-sensitive materials or food because this technique proves capable of eliminating micro-organisms on surfaces without altering the substrate. In the last 10 years, researchers have used nonthermal plasma in a variety of food inoculated with many bacterial species. All of these experiments were conducted exclusively in a laboratory and, to our knowledge, this technique has not been used in an industrial setting. Thus, the purpose of this review is to understand whether this technology could be used at the industrial level. The latest researches using nonthermal plasma on fresh produce were analysed. These evaluations have focused on the log reduction of micro-organisms and the treatment time.

Mutual growth-promoting effect between Bifidobacterium bifidum WBBI03 and Listeria monocytogenes CMCC 54001

In this study, Bifidobacterium bifidum WBBI03 and Listeria monocytogenes CMCC 54001 were selected to detect the changes in their growth pattern after mutual interaction between them. The proteomic changes after the interaction between the 2 bacteria were detected by the isobaric tags for relative and absolute quantitation method. The proteins related to the biosynthesis and cell reproduction were selected, and their changes at the transcriptional level were monitored by fluorescent quantitative PCR. Also, 3 other types of probiotic organisms and opportunistic pathogens were used to verify the results mentioned above. The results showed that growing the 2 organisms together could promote the growth of each other, resulting in earlier entry into the logarithmic phase. The results also showed that the expression of these proteins mostly tended to be upregulated at the translational and transcriptional level. The increase in the expression of these proteins might help promote the growth and reproduction of B. bifidum WBBI03 and L. monocytogenes CMCC 54001. One aspect of the biological significance of their presence in the normal intestine may be that the opportunistic pathogens promote the growth of the probiotics.

ACG Clinical Guideline: Diagnosis, Treatment, and Prevention of Acute Diarrheal Infections in Adults

Acute diarrheal infections are a common health problem globally and among both individuals in the United States and traveling to developing world countries. Multiple modalities including antibiotic and non-antibiotic therapies have been used to address these common infections. Information on treatment, prevention, diagnostics, and the consequences of acute diarrhea infection has emerged and helps to inform clinical management. In this ACG Clinical Guideline, the authors present an evidence-based approach to diagnosis, prevention, and treatment of acute diarrhea infection in both US-based and travel settings.

Defining and Assessing Public Health Functions: A Global Analysis

Given the broad scope and intersectoral nature of public health structures and practices, there are inherent difficulties in defining which services fall under the public health remit and in assessing their capacity and performance. The aim of this study is to analyze how public health functions and practice have been defined and operationalized in different countries and regions around the world, with a specific focus on assessment tools that have been developed to evaluate the performance of essential public health functions, services, and operations. Our review has identified nearly 100 countries that have carried out assessments, using diverse analytical and methodological approaches. The assessment processes have evolved quite differently according to administrative arrangements and resource availability, but some key contextual factors emerge that seem to favor policy-oriented follow-up. These include local ownership of the assessment process, policymakers' commitment to reform, and expert technical advice for implementation.

Antibacterial Activity of Shikimic Acid from Pine Needles of Cedrus deodara against Staphylococcus aureus through Damage to Cell Membrane

Shikimic acid (SA) has been reported to possess antibacterial activity against Staphylococcus aureus, whereas the mode of action of SA is still elusive. In this study, the antibacterial activity and mechanism of SA toward S. aureus by cell membrane damage was investigated. After SA treatment, massive K⁺ and nucleotide leakage from S. aureus, and a significant change in the membrane potential was observed, suggesting SA may act on the membrane by destroying the cell membrane permeability. Through transmission electron microscopic observations we further confirmed that SA can disrupt the cell membrane and membrane integrity. Meanwhile, SA was found to be capable of reducing the membrane fluidity of the S. aureus cell. Moreover, the fluorescence experiments indicated that SA could quench fluorescence of Phe residues of the membrane proteins, thus demonstrating that SA can bind to S. aureus membrane proteins. Therefore, these results showed the antibacterial activity of SA against S. aureus could be caused by the interactions of SA with S. aureus membrane proteins and lipids, resulting in causing cell membrane dysfunction and bacterial damage or even death. This study reveals the potential use of SA as an antibacterial agent.

The effective differentiation of Salmonella isolates using four PCR-based typing methods

AIMS

Discrimination of Salmonella strains below the species level is very important to trace the source of outbreaks. To this end molecular typing methods can be successfully applied to routine analysis in nonspecialized laboratories due to their simplicity and speed. Here, the discriminatory ability of four molecular typing methods was investigated in 74 Salmonella enterica isolates.

METHODS AND RESULTS

Salmonella strains isolated from human stool, blood, bone marrow, synovial fluid, ascites and urine sources in Iran during the years 2012 and 2013 were differentiated by random amplification of polymorphic DNA (RAPD), enterobacterial repetitive intergenic consensus (ERIC), repetitive extragenic palindromic (REP) and BOX repeat-based (BOXAIR) PCR methods. A total of 74 isolates were obtained, with 67 isolates belonging to eight serotypes/serogroups, while seven were nontypeable. The 74 strains produced 32 fingerprints with OPS-11 primers, 44 RAPD fingerprints using OPP-16 primers and 54 fingerprints with P1254 primers; their discriminatory index (DI) was 0·942, 0·978, and 0·984 respectively. BOXAIR fingerprinting produced 49 patterns (DI 0·985), while REP resulted in 55 patterns (DI 0·991) and ERIC in 48 fingerprints (DI 0·983). The discrimination of Salmonella isolates was improved when methods were combined. The combination of ERIC, REP and BOXAIR as well as the combination of BOXAIR with ERIC or REP could differentiate all 74 investigated Salmonella strains.

CONCLUSIONS

The combined use of RAPD and ERIC fingerprinting offers an excellent means of differentiating Salmonella strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

The discrimination power of Salmonella molecular typing by combination of ERIC, REP and BOXAIR methods, or by combination of BOXAIR with ERIC or REP, is sufficient to determine genetic relationships for epidemiological purposes.

The anti-infective activity of punicalagin against Salmonella enterica subsp. enterica serovar typhimurium in mice

Punicalagin, a major bioactive component of pomegranate peel, has an anti-infective effect againstS. typhimuriuminfection in mice.

Pathogen reduction in minimally managed composting of bovine manure

Spread of manure pathogens is of considerable concern due to use of manure for land application. In this study, the effects of four static pile treatment options for bovine manure on die-off of a generic Escherichia coli, E. coli O157:H7 surrogate, Salmonella Senftenberg, Salm. Typhimurium, and Listeria monocytogenes were evaluated. Bovine manure spiked with these bacteria were placed in cassettes at the top, middle, and bottom sections of four static pile treatments that reflect minimal changes in pile construction with and without straw. Temperatures were monitored continuously during the 28 day self-heating period. E. coli and salmonellae were reduced from 8 to 9 log10 CFU g(-1) to undetectable levels (<1.77 log10 MPN g(-1)) at 25-30 cm depths within 7 days in all pile sections except for the manure-only pile in which 3-4 logs of reduction were obtained. No L. monocytogenes initially present at 6.62 log10 CFU g(-1) were recovered from straw-amended piles after 14 days, in contrast with manure-only treatment in which this pathogen was recovered even at 28 days. Decline of target bacterial populations corresponded to exposure to temperatures above 45°C for more than 3 days and amendments of manure with straw to increase thermophilic zones. Use of straw to increase aeration, self-heating capacity, and heat retention in manure piles provides producers a minimal management option for composting that enhances pathogen die-off and thereby reduces risk of environmental spread when manure is applied to land.