Food Poisoning Research Articles

Evaluation of Fungicides Against Rhizoctonia bataticola (Taub) Butler Causing Dry Root Rot of Groundnut and Their Compatability with Trichoderma asperellum

The efficacy of four systemic and combination fungicides, namely Carbendazim 12% + Mancozeb 63% WP, Tebuconazole 25% WG, Hexaconazole 4% + Zineb 68% WG, and Tebuconazole 50% + Trifloxystrobin 25% WG, against Rhizoctonia bataticola, the causal agent of dry root rot in groundnut was evaluated using the poison food technique. Among the tested fungicides, Hexaconazole 4% + Zineb 68% WG exhibited the highest efficacy, with 100% inhibition of mycelial growth at all concentrations tested. Tests of compatibility of these fungicides with Trichoderma asperellum revealed that Hexaconazole 4% + Zineb 68% WG caused 38.88% of growth inhibition in T. asperellum while the other fungicides tested were totally incompatible with100 percent inhibition.

Efficacy of Various Fungicides and Herbicides for the Management of Wheat Foot Rot Disease

The present research was conducted to investigate and assess the effectiveness of fungicides and herbicides in controlling the foot rot disease caused by the fungus Sclerotium rolfsii in wheat crops. Foot rot of wheat caused by Sclerotium rolfsii Sacc. has a major constraint and potential threat to successful wheat cultivation. Therefore affords were made to screen the different systemic, contact and combination of fungicides and herbicides in vitro condition against Sclerotium rolfsii. Different fungicides against S. rolfsii were tested in vitro. The efficacy of two systemic fungicides (Tricyclazole 75%W.P. & Carbendazim 50% WP); two non-systemic fungicides (Mancozeb 75%WP & Copper oxychloride 50% WP); one contact fungicides Propineb 70%WP and one combo fungicides (Metalaxyl 8%+Mancozeb 64%) were evaluated at different concentrations (50,150 and 250 ppm) on the development of S. rolfsii on Potato dextrose agar (PDA) medium using poisoned food technique. Among the six fungicides, Mancozeb was found best at all the concentrations followed by Tricyclazole at higher concentrations which inhibit the growth of S. rolfsii. Another method used for management strategy was herbicide for inhibiting the mycelial growth of S. Rolfsii. In vitro efficacy of selective herbicides viz. (Metribuzin 70% WP & Oxadiargyl 80% WP), systemic herbicide viz. (Pyrazosulfuron Ethyl 10% WP & Metsulfuron Methyl 20% WP) and one combo herbicides viz. (Bensulfuron Methyl 0.6% + Pretilachlor 6% GR) were tested at their recommended concentrations. Among them metribuzin showed 80.00 % growth inhibition, succeeded by Pyrazosulfuron ethyl (51.85%) and Bensulfuron methyl + Pretilachlor (45.92%).

Development of IMBs-qPCR method for detection of foodborne Salmonella

Rapid and accurate detection of pathogenic microorganism is critical for food safety. Salmonella is one of the common causes of food poisoning. In the present work, polyclonal antibody against the recombinant PagN protein was prepared, and coupled with carboxylated magnetic beads to form immunomagnetic beads (IMBs) for capturing Salmonella, which was then combined with qPCR technology which used the specific primers of invA gene to accurately quantify the number of colonies, thus establishing the IMBs-qPCR method for detection of Salmonella. 0.2 mg IMBs could specifically concentrate Salmonella, with the stable capturing efficiency of 80%, corresponding to the concentrations of 102 - 105 CFU/mL. The minimum detection limit concentration was 101 CFU/mL. The method was applied for detection and enumeration of Salmonella in pork and milk samples, and the capture efficiency of 77.38 and 80.92% were obtained. In summary, the IMBs-qPCR method established herein could effectively detect Salmonella with good specificity and sensitivity. The whole detection time was less than 9 h, which laid a foundation for development of a rapid detection kit for foodborne pathogens.

Pseudomonas aeruginosa SWUC02 Cell-Free Culture as a Potential Antimicrobial Agent Against Household Antibiotics-Resistant Staphylococcus aureus

Contamination of household environments with pathogenic bacteria poses a significant risk of foodborne illnesses. This study aimed to investigate the effectiveness of cell-free culture obtained from Pseudomonas aeruginosa SWUC02 (CF-SWUC02) against Staphylococcus aureus, a common pathogen associated with food poisoning outbreaks. The antagonistic activity of P. aeruginosa SWUC02 and CF-SWUC02 against various pathogenic bacteria, particularly S. aureus, was assessed. The active antimicrobial compounds produced by P. aeruginosa SWUC02 demonstrated resistance to protease enzymes and high temperatures. Optimal culture conditions for inhibiting S. aureus were determined as LB media supplemented with 0.01% CuCl2, inoculated with 1x105 CFU.mL-1 of P. aeruginosa SWUC02, and incubated at 32°C with agitation (100 rpm) for 12 days. Eighty-six S. aureus isolates were collected from household environments and tested for antibiotic resistance, with 55 isolates exhibiting resistance to penicillin, and 17 isolates were identified as methicillin-resistant S. aureus (MRSA). CF-SWUC02 demonstrated inhibitory effects against all S. aureus isolates, including MRSA. In conclusion, CF-SWUC02 displayed antagonistic activity against drug resistant S. aureus, suggesting its potential as a valuable resource for combating these pathogens. Furthermore, the presence of heat and protease stable antimicrobial compounds in CF-SWUC02 highlights the need for further investigation to explore their potential applications in the field of antimicrobial research.

Molecular characterization of enterotoxin genes in methicillin-resistant S. aureus isolated from food poisoning outbreaks in Egypt

BackgroundStaphylococcus aureus (S. aureus), especially methicillin-resistant S. aureus (MRSA), is a known disease-causing bacteria with many associated health hazards. Staphylococcal food poisoning can result from staphylococcal enterotoxins (SEs).MethodsIn this study, 50 S. aureus isolates were isolated from the gastrointestinal tract (GIT) clinical samples of patients with food poisoning in clinical laboratories at Mansoura University Hospital, Egypt. For determination their antibiogram, these isolates were tested for antimicrobial sensitivity against 12 antimicrobial agents using the agar disk diffusion test. After DNA extraction from the isolates, conventional polymerase chain reaction (PCR) was used to detect mecA and SEs genes.ResultsAs a result, all isolates were ampicillin and cefoxitin-resistant, while 86% (43 of 50) of the tested isolates exhibited multidrug resistance (MDR). In contrast, the highest sensitivity was confirmed against vancomycin, linezolid and quinolones, namely ciprofloxacin and norfloxacin. Although 100% of the isolates were mecA positive, staphylococcal enterotoxin genes set-A, set-B, set-C, set-G, set-M, and set-O genes were detected in 56%, 20%, 8%, 32%, 16%, and 24%, of the tested isolates, respectively. Finally, isolates encompassing SEs genes were used to validate a microarray chip, indicating its potential for a better methodological approach for detecting and identifying SEs in human samples.ConclusionThe genotypic findings of this study may help explain the enterotoxigenic patterns in S. aureus among Egyptian patients with food poisoning.

Quantitative analysis of lycorine dietary exposure in commercial foods and the Amaryllidaceae family

Lycorine, a prominent alkaloid found in the Amaryllidaceae plant family, is known for its therapeutic properties and potential applications. However, excessive lycorine consumption can cause food poisoning and other detrimental health effects. This study focuses on the quantitative measurement of lycorine levels in commercially available foods and an evaluation of dietary exposure. With regard to this, considerable research has not been conducted to date. For the analysis of lycorine, a Quick, Easy, Cheap, Effective, Rugged, Safe (QuEChERS) technique, and a liquid chromatography-tandem mass spectrometry method were developed, validated, and applied to 56 commercial food samples and 5 Amaryllidaceae plants. The calculated dietary exposure ranged from 0.0 to 3.77 × 10−4 and 0.39–4.72 µg/kg bw/day in lycorine detected foods and Amaryllidaceae plants, respectively (Allium cepa, Allium hookeri, Allium monanthum, Perilla leaves, and Amaryllidaceae plants). Foods in the Amaryllidaceae family were more likely to contain lycorine, with onion identified as a primary food source contributing to lycorine exposure. These findings help to accurately determine the lycorine content in foods, identify potential benefits and risks associated with the consumption of lycorine-containing foods, and may support the need for further research to establish appropriate guidelines for the consumption of these foods.

Antibacterial and antifungal activity of Lavandula angustifolia and Thymus vulgaris essential oils grown in the Algerian west coast

ABSTRACT The screening of natural products in the quest for new antimicrobial and antifungal agents has become the need of the hour in order to combat drug-resistant pathogenic microbes.The aim was to evaluate the antibacterial and antifungal activities of Lavandula angustifolia and Thymus vulgaris essential oils (EOs).The antimicrobial activity was tested on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus using agar disc diffusion and the antifungal screening was done in the same way against Candida albicans. The Thymus Vulgaris EO collected from Oran was very active against Staphylococcus aureus and Candida albicans. Lavandula angustifolia EO collected from Oran was extremely active against Pseudomonas aeruginosa and Candida albicans, Candida albicans was the most sensitive to the essential oils. Essential oils of L. angustifolia and T. vulgaris are highly effective natural antibacterial and antifungal agents that can be used to treat infections and food poisoning.

Allergie alimentaire chez l’enfant : éviter les erreurs diagnostiques

A clinical manifestation occurring after a meal is not always caused by a food allergy. The semiological analysis, the time of onset between exposure and signs, the consideration of favorable or confounding circumstances or the selection of the probable allergen are necessary data for etiological diagnosis. There are many differential patterns depending on the clinical presentation and age, such as non-specific release of histamine, viral urticaria, auriculo-temporal syndrome, food poisoning, acute gastroenteritis for exemple. The practitioner can also be mistaken in his diagnostic approach by a wrong selection and/or interpretation of paraclinical explorations. The main purpose is to avoid inadequate medical follow-up and useless avoidance diet.

In vitro Antagonism of Trichoderma Isolates and Efficacy of Chemical Fungicides against Mycelial Growth of Pestalotiopsis theae

Grey leaf blight, one of the most important fungal foliar diseases of tea is caused by Pestalotiopsis spp. An in vitro study was conducted at Agriculture Research Station, Pakhribas to evaluate bio-efficacy of two Trichoderma isolates namely Trichoderma viride and Trichoderma harzianum using dual culture technique. Similarly comparative efficacy of five fungicides viz. Copper Oxychloride 50% WP, Carbendazim 50% WP, Metalaxyl 8% WP + Mancozeb 64 % WP, Carboxin 37.5% WS + Thiram 37.5% WS and Hexaconazole 5% EC at four different concentration of 50 ppm, 100 ppm, 200 ppm and 500 ppm was tested using poisoned food technique. The experiment was arranged in a completely randomized design with three replications for each treatment and a control. Trichoderma viride and Trichoderma harzianum exhibited 66.64% and 62.32% growth inhibition respectively against Pestalotiopsis theae. Growth inhibition by fungicides ranged from 35% to 100%. Hexaconazole exhibited complete mycelial growth inhibition (100%) regardless of concentration. This complete inhibition (100%) in colony growth was recorded at 200 ppm and 500 ppm of Carboxin + Thiram and then in Metalaxyl + Mancozeb at 500 ppm. While least (35.62%) inhibition on mycelial growth of P. theae was observed with Copper Oxychloride at 50 ppm. There was significant reduction in colony growth of P. theae with each treatment at all concentration in comparison to control. This study indicated significant results by fungicides even at lower concentration and by both Trichoderma spp. This study established Trichoderma spp as a successful alternative and hence recommends use of an integrated approach with both effective fungicides at low concentration and bio-control agents in further managing grey leaf blight of tea plant after subsequent field trials.

Compatibility of indigenous <i>Trichoderma asperellum</i> with chemical fungicides for the management of chickpea wilt

Trichoderma asperellum is an antagonistic fungus, which has the ability to inhibit the growth of pathogens in target environment. The study on compatibility of T. asperellum with fungicide molecules was carried out to know its compatibility with different classes of fungicide molecules during the studies on antagonistic potential of Trichoderma sp. against Fusarium oxysporum f. sp. ciceris causing chickpea wilt. In the present study, each of six popular systemic, non-systemic and combi-fungicide molecules were used to study the compatibility with bioagent Trichoderma asperellum. The fungicides were used at three different concentrations, i.e., systemic fungicides at 0.05, 0.1 and 0.15 per cent and non-systemic and combi fungicides at 0.1, 0.2 and 0.3 per cent concentrations by using poisoned food technique. Among six systemic fungicides, only azoxystrobin was highly compatible, whereas other systemic fungicides were incompatible showing 100 per cent inhibition of T. asperellum. Among six non-systemic fungicides, propineb, copper oxychloride and copper hydroxide were compatible at all three concentrations tested. However, mancozeb was compatible at lower concentrations but incompatible at higher (0.3%) concentrations. Further, thiram and captan were highly incompatible. Among six combi fungicides, copper oxychloride + copper hydroxide and cymoxanil + mancozeb were compatible with T. asperellum.

Efficacy of Non-Conventional Chemical Inducers against Fusarium oxysporum Inciting Wilt in Chilli

Chilli wilt incited by Fusarium oxysporum is the most devastating disease, causing substantial yield losses throughout chilli growing areas of the world. Fusarium oxysporum is a soil-borne fungus which survives for several years in soil. The disease is favoured by high temperature and high moisture, this condition plays significant role in development of wilt symptoms. The disease management using chemicals is economically not feasible and is also unsafe for the environment. Due to growing public awareness to environment and human health, need of the hour is to find alternate approaches for disease management. Therefore, to investigate induction of systemic resistance against Fusarium oxysporum in chilli. Different non-conventional chemical inducers like salicylic acid (SA), jasmonic acid (JA), Indole acetic acid (IAA), Indole butyric acid (IBA), chitosan, salicylic acid nano formulation and chitosan nano formulation were used in an experiment conducted in Department of plant pathology, Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana. These non-conventional chemicals with four concentrations 25, 50, 75 and 100 µg/ml were evaluated for their antifungal activity against Fusarium oxysporum under in vitro condition using poison food technique with four replications. It was found that the highest mycelial growth inhibition was observed in salicylic acid nano formulation (79.73%) at 100 µg/ml concentration followed by Jasmonic acid (77.12%) at 100 µg/ml concentration and the lowest growth inhibition was recorded in Indole acetic acid (27.15%) at 100 µg/ml concentration. The same trend was observed when chilli varieties Pusa Jwala (susceptible) and Pusa Sadabahar (moderately resistant) were tested with the two best and the least effective non-conventional chemical inducer obtained in vitro for measuring the disease severity in screen house. This insight clarifies the scope of using non-conventional chemical inducers as an effective disease management strategy against Fusarium wilt of chilli.

Epidemiological and molecular evidence of foodborne poisoning outbreak caused by enterotoxin gene cluster-harboring Staphylococcus aureus of new sequence type 7591

ObjectivesThis paper presented a detailed analysis of the epidemiology and molecular characteristics of staphylococcal food poisoning (SFP) that occurred in a hotel in Hangzhou. MethodsA total of 46 guests at the hotel underwent an epidemiological survey. Samples of stool from patients, vomit, swabs from the kitchen, leftover food items, and anal swabs from food handlers were taken and investigated for the presence of potential pathogenic bacteria. Molecular techniques and whole genome sequencing were performed to track the evolution of Staphylococcus aureus associated with the outbreak of SFP. ResultsForty-six individuals displayed gastrointestinal symptoms. Seventeen isolates of S. aureus were discovered to carry the seg, sei, sem, sen, seo, and selu genes found in a specific enterotoxin gene cluster (egc) operon, but without the presence of classical enterotoxins such as SEA ∼ SEE. All egc-positive isolates shared identical pulsed-field gel electrophoresis profiles and were classified under new ST7591 (Clonal Complex 72) with identical spa typing t148. In addition, some isolates of S. aureus obtained from food sources sold in Hangzhou over the past 3 years and carrying egc genes were grouped under the ST72 lineage (CC72). Through whole genome sequencing, a strong genetic connection was revealed between these egc-positive isolates and clinical ST72 S. aureus found in China. ConclusionsS. aureus with non-classical egc enterotoxins was suggested to be a potential cause of SFP in humans.

Estimation of the time of exposure based on interval and censored data using the ε-accelerated EM algorithm.

Accurately estimating the timing of pathogen exposure plays a crucial role in outbreak control for emerging infectious diseases, including the source identification, contact tracing, and vaccine research and development. However, since surveillance activities often collect data retrospectively after symptoms have appeared, obtaining accurate data on the timing of disease onset is difficult in practice and can involve "coarse" observations, such as interval or censored data. To address this challenge, we propose a novel likelihood function, tailored to coarsely observed data in rapid outbreak surveillance, along with an optimization method based on an -accelerated EM algorithm for faster convergence to find maximum likelihood estimates (MLEs). The covariance matrix of MLEs is also discussed using a nonparametric bootstrap approach. In terms of bias and mean-squared error, the performance of our proposed method is evaluated through extensive numerical experiments, as well as its application to a series of epidemiological surveillance focused on cases of mass food poisoning. The experiments show that our method exhibits less bias than conventional methods, providing greater efficiency across all scenarios.

Oxigenic Profiling and Antibiotic Resistance of Baclllus cereus Strains Isolated from Food Consumed By School Children In Ilorin Metropolis

Background: Food poisoning is caused by toxin produced by pathogenic organisms like bacteria, viruses etc. These toxins are common causes of food borne illness. This study was carried out to determine the antibiotic susceptibility pattarn and molecular identity of enterotoxigenic Bacillus cereus strains isolated from food consumed by school children in Ilorin metropolis Methods: Bacterial isolates that were identified as Bacillus cereus (OQ235070), Bacillus cereus (OQ235071), Bacillus cereus (OQ235072), Bacillus cereus (OQ235073), Bacillus thuringiensis (OQ235074), Bacillus cereus (OQ235075) and Bacillus cereus (OQ235076) were obtained from culture collection from Microbiology laboratory, Kwara State University, Nigeria were used for this research. Antibiotic susceptibility test was carried out on the isolates using standard technique. Detection of resistance gene, plasmid profiling and curing, and detection of enterotoxigenic genes were done using standard microbiological methods. Results: All the isolates were resistant to minimum of two antibiotics before and after plasmid cur-ing. A total of 98 % of the isolates were susceptible to ofloxaxin, centamincin, pefloxacin, and augmentin while 90 % of the isolates were resistance to amoxylin, streptomycin, and chloramphenicol. Plasmid profiling shows that the bacteria harbored mega plasmid with equal size of 5000 bp. Curing removed all plasmid, presence of enterotoxin virulence gene nhe A, B, C and hbl C, D were observed but hbl A was not found. Conclusion: The Bacillus species studied were found to be multi-drug resistant and carried entero-toxigenic genes which were chromosomally borne.

Assessment of bacterial and fungal contamination in Suya – a public health concern

Ready-to-eat meat products offer numerous benefits, but improper handling can pose severe threats to human health. Due to its short life span, there is a need for adequate handling and preservation to prevent microbial contamination. Suya, a popular ready-to-eat meat product consumed in Nigeria, can be a major source of food poisoning if not processed and handled properly because it can predispose its consumers to pathogenic microorganisms, heavy metals which result from contaminated water and utensils used during processing, and polycyclic aromatic hydrocarbons from the incomplete combustion during roasting of the meat. Staphylococcus spp., (95.2%), Escherichia coli (90.5%), Bacillus sp. (66.7%), Salmonella (55%), Klebsiella sp. (52.4%) were the most identified bacteria contaminants. While Aspergillus spp. (commonly flavus, niger, and fumigatus) were identified in all 11 reports that identified fungal contamination, followed by Penicillium spp., (81.8%), Rhizopus spp. (63.6%), Mucor spp. (54.5%) and Candida albicans (45.5%). Infestation by Taenia sp (67%), A. lumbricoides (50%), E. histolytica (41.7%), G. lamblia (25%), and Hookworm (16.7%) were also identified. Microbial contaminants were also identified in spices meant to supplement and improve suya's organoleptic and nutritional value. Microbial isolates from suya samples displayed resistance to some commonly used antibiotics, raising concerns about antibiotic resistance development. Suya is one of the unsafe ready-to-eat meat products to consume in Nigeria due to the unhygienic practices during its processing and packaging, such as bare-hand contact, exposure to vehicular emissions, or other environmental contaminants, and packaging in inked papers with contaminants, which makes it unfit for human consumption. This review underscores the importance of identifying and addressing these areas of contamination during suya preparation, production, packaging, and consumption. There is a dire need to educate suya vendors, consumers, and policymakers on food safety and the need for hygienic practices during suya production to safeguard public health.

Phage-Based Biosensing for Rapid and Specific Detection of Staphylococcus aureus.

Staphylococcus aureus (S. aureus) is a major foodborne pathogen. Rapid and specific detection is crucial for controlling staphylococcal food poisoning. This study reported a Staphylococcus phage named LSA2302 showing great potential for applications in the rapid detection of S. aureus. Its biological characteristics were identified, including growth properties and stability under different pH and temperature conditions. The genomic analysis revealed that the phage has no genes associated with pathogenicity or drug resistance. Then, the phage-functionalized magnetic beads (pMB), serving as a biological recognition element, were integrated with ATP bioluminescence assays to establish a biosensing method for S. aureus detection. The pMB enrichment brought high specificity and a tenfold increase in analytical sensitivity during detection. The whole detection process could be completed within 30 min, with a broad linear range of 1 × 104 to 1 × 108 CFU/mL and a limit of detection (LOD) of 2.43 × 103 CFU/mL. After a 2 h pre-cultivation, this method is capable of detecting bacteria as low as 1 CFU/mL. The recoveries of S. aureus in spiked skim milk and chicken samples were 81.07% to 99.17% and 86.98% to 104.62%, respectively. Our results indicated that phage-based biosensing can contribute to the detection of target pathogens in foods.

Bioinformatic Analysis of Secondary Metabolite Biosynthetic Potential in Pathogenic Fusarium.

Fusarium species are among the filamentous fungi with the most pronounced impact on agricultural production and human health. The mycotoxins produced by pathogenic Fusarium not only attack various plants including crops, causing various plant diseases that lead to reduced yields and even death, but also penetrate into the food chain of humans and animals to cause food poisoning and consequent health hazards. Although sporadic studies have revealed some of the biosynthetic pathways of Fusarium toxins, they are insufficient to satisfy the need for a comprehensive understanding of Fusarium toxin production. In this study, we focused on 35 serious pathogenic Fusarium species with available genomes and systematically analyzed the ubiquity of the distribution of identified Fusarium- and non-Fusarium-derived fungal toxin biosynthesis gene clusters (BGCs) in these species through the mining of core genes and the comparative analysis of corresponding BGCs. Additionally, novel sesterterpene synthases and PKS_NRPS clusters were discovered and analyzed. This work is the first to systematically analyze the distribution of related mycotoxin biosynthesis in pathogenic Fusarium species. These findings enhance the knowledge of mycotoxin production and provide a theoretical grounding for the prevention of fungal toxin production using biotechnological approaches.

Analysis of reservoir sources of Campylobacter isolates to free-range broilers in Denmark

Campylobacter is a common cause of food poisoning in many countries, with broilers being the main source. Organic and free-range broilers are more frequently Campylobacter-positive than conventionally raised broilers and may constitute a higher risk for human infections. Organic and free-range broilers may get exposed to Campylobacter from environmental reservoirs and livestock farms, but the relative importance of these sources is unknown. The aim of the study was to describe similarities and differences between the genetic diversity of the Campylobacter isolates collected from free-range/organic broilers with those isolated from conventional broilers and other animal hosts (cattle, pigs, and dogs) in Denmark to make inferences about the reservoir sources of Campylobacter to free-range broilers. The applied aggregated surveillance data consisted of sequenced Campylobacter isolates sampled in 2015 to 2017 and 2018 to 2021. The data included 1,102 isolates from free-range (n=209), conventional broilers (n=577), cattle (n=261), pigs (n=30), and dogs (n=25). The isolates were cultivated from either fecal material (n=434), food matrices (n=569), or of nondisclosed origin (n=99). Campylobacter jejuni (94.5%) dominated and subtyping analysis found 170 different sequence types (STs) grouped into 75 clonal complexes (CCs). The results suggest that CC-21 and CC-45 are the most frequent CCs found in broilers. The relationship between the CCs in the investigated sources showed that the different CCs were shared by most of the animals, but not pigs. The ST-profiles of free-range broilers were most similar to that of conventional broilers, dogs and cattle, in that order. The similarity was stronger between conventional broilers and cattle than between conventional and free-range broilers. The results suggest that cattle may be a plausible reservoir of C. jejuni for conventional and free-range broilers, and that conventional broilers are a possible source for free-range broilers or reflect a dominance of isolates adapted to the same host environment. Aggregated data provided valuable insight into the epidemiology of Campylobacter sources for free-range broilers, but time-limited sampling of isolates from different sources within a targeted area would hold a higher predictive value.

A Metal Organic Framework-Based Light Scattering ELISA for the Detection of Staphylococcal Enterotoxin B

Enzyme-linked immunosorbent assay (ELISA) is one of the most commonly used method for the detection of staphylococcal enterotoxin B (SEB), the main protein toxin causing staphylococcal food poisoning. However, the traditional ELISA reaction needs to be stopped by sulfuric acid to obtain stable colorimetric signal, and it is easily influenced by a colored sample. In order to address this problem, a new ELISA method using zeolite imidazolate skeleton-8 metal-organic framework (ZIF-8 MOF) as a light scattering (LS) reporter for SEB detection was developed in this work. ZIF-8 MOF has the characteristics of high porosity, large specific surface area, clear pore structure, and adjustable size, which is one of the most representative MOFs constructed from Zn2+ and 2-methylimidazole (2-mIM). The 2-mIM ligand of ZIF-8 exhibited antioxidant activity and can strongly react with H2O2, which could destroy the structure of ZIF-8, resulting in the obvious decrease in LS intensity. We combined this specific reaction with the sandwich immune reaction to construct the LS ELISA method for the successful detection of SEB. This method is more reliable than commercial tests kits for the detection of colored samples, and it is simple, sensitive, and selective, and has great potential in the detection of other toxins by simply changing the corresponding recognition units.

Evaluation of Bacterial Activity Based on the Electrochemical Properties of Tetrazolium Salts.

This study focused on the electrochemical properties of tetrazolium salts to develop a simple method for evaluating viable bacterial counts, which are indicators of hygiene control at food and pharmaceutical manufacturing sites. Given that the oxidized form of 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), which has excellent cell membrane permeability, changes to the insoluble reduced form of formazan inside the cell, the number of viable cells was estimated by focusing on the reduction current of MTT remaining in the suspension. Dissolved oxygen is an important substance for bacterial activity; however, it interferes with the electrochemical response of MTT. We investigated the electrochemical properties of MTT to obtain a potential-selective current response that was not affected by dissolved oxygen. Real-time observation of viable bacteria in suspension revealed that uptake of MTT into bacteria was completed within 10 min, including the lag period. In addition, we observed that the current response depends on viable cell density regardless of the bacterial species present. Our method enables a rapid estimation of the number of viable bacteria, making it possible to confirm the safety of food products before they are shipped from the factory and thereby prevent food poisoning.