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This paper aims to report a prototype of a reliable method for rapid, sensitive bacterial detection by using a low-cost zinc oxide nanorods (ZnONRs)-based electrochemical sensor.

The ZnONRs have been grown on the surface of a disposable, miniaturized working electrode (WE) using the low-temperature hydrothermal technique. Scanning electron microscopy and energy dispersion spectroscopy have been performed to characterize the distribution as well as the chemical composition of the ZnONRs on the surface, respectively. Moreover, the cyclic voltammetry test has been implemented to assess the effect of the ZnONRs on the signal conductivity between −1 V and 1 V with a scan rate of 0.01 V/s. Likewise, the effect of using different bacterial concentrations in phosphate-buffered saline has been investigated.

The morphological characterization has shown a highly distributed ZnONR on the WE with uneven alignment. Also, the achieved response time was about 12 minutes and the lower limit of detection was approximately 103 CFU abbreviation for Colony Forming Unit/mL.

This paper illustrates an outcome of an experimental work on a ZnONRs-based electrochemical biosensor for direct detection of bacteria.

The purpose of this study was to develop flexible sensors for detection of different concentrations of bacteria, such as Pseudomonas aeruginosa and Staphylococcus aureus, in saline.

The sensors were fabricated using ink-jet printing technology and they consist of a pair of silver interdigitated electrodes printed on mechanically flexible substrates – foil and paper. In house measurement setup for testing and characterization of sensors has been developed. Structural, electrical and mechanical properties of flexible sensors have been determined and compared.

The characteristics of sensor – the resonant frequency as a function of different concentrations of each bacteria – are presented. The obtained results demonstrate different resonant frequencies for each dilution of Pseudomonas aeruginosa and Staphylococcus aureus in physiological saline.

Both sensors showed accurate measurements of bacterial count, which can be achieved with detection of resonant frequency, and this is reflective of the number of bacterial cells within a sample.

The findings suggest that the newly developed method based on measuring resonant frequency corresponds well with bacterial cell count, thus establishing a new proof-of-concept that such method can have significant applications in bacterial cell counting that are economic and easily maintained.

Fast, cost-effective, accurate and non-invasive method for detection of different bacteria from saline was developed.

For the first time, comparison between performances of flexible sensors on foil and paper for bacteria detection is demonstrated. Almost linear dependence between shift of resonant frequency of developed sensors and concentration of bacteria has been obtained.

Fresh vegetables contain advantageous phytochemical components, making them one of the most significant sources of nutrition. The threat of harmful bacteria still exists because these vegetables are not heated in restaurants before being consumed. Therefore, this study aimed to evaluate the microbial quality of fresh vegetables in restaurants of different levels.

A total of 499 fresh vegetable samples (from sandwiches and fresh-cut vegetable salads) were collected from 3 different types of food service establishment: 201 from international restaurants (IRs), 210 from national restaurants (NRs), and 88 from cafeterias (CAs). The samples were prepared and inoculated on specific growth media. The aerobic mesophilic bacteria (AMB) Campylobacter spp., Staphylococcus aureus (S. aureus), Enterobacteriaceae, Escherichia coli (E. coli) and yeast and molds were counted, and Listeria monocytogenes, Salmonella spp. and Escherichia coli O157 were detected using specialized medium.

High counts of S. aureus, above 3 log cfu/g, suggested that 71.5% of samples collected from NRs and 77.3% from CA were not accepted, whereas 81.6% of samples collected from IRs were accepted. The low population of E. coli, less than 2 log cfu/g, suggested that 99.0, 97 and 92.0 % of samples collected from IRs, NRs and CA, respectively, were accepted. Listeria monocytogenes and Escherichia coli O157 were absent from every sample. One sample was positive for Salmonella spp. in each of the NR and CA sample groups.

RIs adhere to health and hygiene standards better than NRs and CAs, according to the findings of vegetable contamination tests.

This study aims to study the distribution characteristics of antibiotic resistance in direct-eating food and analysis of Citrobacter freundii genome and pathogenicity. Residual antibiotics and antibiotic resistance genes (ARGs) in the environment severely threaten human health and the ecological environment. The diseases caused by foodborne pathogenic bacteria are increasing daily, and the enhancement of antibiotic resistance of pathogenic bacteria poses many difficulties in the treatment of disease.

In this study, six fresh fruits and vegetable samples were selected for isolation and identification of culturable bacteria and analysis of antibiotic resistance. The whole genome of Citrobacter freundii isolated from cucumber was sequenced and analyzed by Oxford Nanopore sequencing.

The results show that 270 strains of bacteria were identified in 6 samples. From 12 samples of direct food, 2 kinds of probiotics and 10 kinds of opportunistic pathogens were screened. The proportion of Citrobacter freundii screened from cucumber was significantly higher than that from other samples, and it showed resistance to a variety of antibiotics. Whole genome sequencing showed that Citrobacter freundii was composed of a circular chromosome containing signal peptides, transmembrane proteins and transporters that could induce antibiotic efflux, indicating that Citrobacter freundii had strong adaptability to the environment. The detection of genes encoding carbohydrate active enzymes is more beneficial to the growth and reproduction of Citrobacter freundii in crops. A total of 29 kinds of ARGs were detected in Citrobacter freundii, mainly conferring resistance to fluoroquinolones, aminoglycosides, carbapenem, cephalosporins and macrolides. The main mechanisms are the change in antibiotic targets and efflux pumps, the change in cell permeability and the inactivation of antibiotics and the detection of virulence factors and ARGs, further indicating the serious risk to human health.

The detection of genomic islands and prophages increases the risk of horizontal transfer of virulence factors and ARGs, which spreads the drug resistance of bacteria and pathogenic bacteria more widely.

In order to maintain food safety standards, conventional microbiological methods are still being used to detect bacteria and other organisms in food. However, these techniques are not ideal, as often it can be many days before results are known‐which may be of particular economic importance for those foods with a short shelf‐life. The introduction of newer technology, such as nucleic acid probe and related amplification technology in other fields, has transformed the detection of many organisms. The Polymerase Chain Reaction (PCR) allows nucleic acid probes, with their inherent specificity, to be used to detect organisms present in very low numbers within a short period of time. However, at present, in food microbiology, there are technical problems with using the PCR, as certain components in food interfere with the reaction. When these problems are resolved and with prospects for semi‐automation of the PCR technique, there should be enormous potential for the rapid detection of bacteria in foods, with consequent benefits to the food industry and to consumers.

This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation.

The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles.

The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation.

The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.

Nature and occurrence of food-borne pathogens in raw and processed food products evolved greatly in the past few years due to new modes of transmission and resistance build-up against sundry micro-/macro-environmental conditions. Assurance of food health and safety thus gained immense importance, for which bio-sensing technology proved very promising in the detection and quantification of food-borne pathogens. Considering the importance, different studies have been performed, and different biosensors have been developed. This study aims to summarize the different biosensors used for the deduction of food-borne pathogens.

The present review highlights different biosensors developed apropos to food matrices, factors governing their selection, their potential and applicability. The paper discusses some related key challenges and constraints and also focuses on the needs and future research prospects in this field.

The shift in consumers’ and industries’ perceptions directed the further approach to achieve portable, user and environmental friendly biosensing techniques. Despite of these developments, it was still observed that the comparison among the different biosensors and their categories proved tedious on a single platform; since the food matrices tested, pathogen detected or diagnosed, time of detection, etc., varied greatly and very few products have been commercially launched. Conclusively, a challenge lies in front of food scientists and researchers to maintain pace and develop techniques for efficiently catering to the needs of the food industry.

Biosensors deduction limit varied with the food matrix, type of organism, material of biosensors’ surface, etc. The food matrix itself consists of complex substances, and various types of food are available in nature. Considering the diversity of food there is a need to develop a universal biosensor that can be used for all the food matrices for a pathogen. Further research is needed to develop a pathogen-specific biosensor that can be used for all the food products that may have accuracy to eliminate the traditional method of deduction.

The present paper summarized and categorized the different types of biosensors developed for food-borne pathogens.

This study aims to monitor seawater by determing two biological indicators, Escherichia coli and Enterococcus faecalis. The process of following standard procedures is mainly time-consuming. Thus, there is a demand for a biosensor, an appropriate device for rapid and accurate results that can give information about the microbiological quality of seawater in an effective and rapid way.

In the gold standard method for seawater monitoring, the filter method is applied as a condensation step. In this work, the authors evaluated six types of common syringe filters for bacteria concentration and then the best filter was used for seawater analysis for E. coli and Enterococci with loop-mediated isothermal amplification (LAMP) polymerase chain reaction (PCR).

Cellulose acetate filter had the highest efficiency (98%) for bacterial concentration. The limit of detection of the LAMP method was 104/1,000 mL for both E. coli and E. faecalis. The proposed method could be used for the development of seawater biosensors with advantages such as a simple heating element and the speed that the LAMP PCR presents.

The suggested protocol is proposed in an integrated in situ system, a biosensor, for seawater quality determination.

This paper seeks to optimize a multiplex PCR in order to detect the incidence of Salmonella and Escherichia coli (E. coli) in chicken carcasses, eliminating a pre‐culture enrichment step and the pathogen isolation.

A total of 30 chicken rinse carcasses were analysed by standard microbiological methods, and the isolates were identified by biochemical and serological tests. The results were compared with those obtained by a multiplex PCR using validated primers targeting for invA and lamB genes of Salmonella and E. coli, respectively.

Microbiological analysis showed the prevalence of Salmonella in 14 out of 30 chicken carcasses. The same rinse samples were also analysed by multiplex PCR, which allowed the simultaneous detection of both bacteria directly from the chicken rinse water microbial community.

The optimized mPCR detected enterobacteria directly from the rinse samples, a complex matrix food, in one workday. There was 100 per cent agreement of the conventional microbiological analysis with those results obtained by multiplex PCR.