Nonculturable Escherichia coli O157 in horticultural compost: a public health concern

Fresh produce-associated outbreaks of the foodborne pathogen Escherichia coli O157 are responsible for a number of disease cases, hospitalisations, and deaths. In many cases, the source of contamination can be linked to the growing media of the food, although pathogen detection is problematic in these complex soil ecosystems. In this study, direct qPCR without pre-enrichment was used to detect 310 copies of the translocated intimin receptor gene, using a primer sequence specific to E. coli O157, in horticultural compost purchased from a commercial supplier. The pathogen could not be cultured on selective media but was visualised using peptide nucleic acid fluorescence in situ hybridisation and cell elongation viability assay, confirming the viability. Enumeration of elongated E. coli O157 determined that there were 205 live cells per gram compost. The nonculturability and confirmation of viability of the pathogen indicates its viable but nonculturable (VBNC) status. The detection of VBNC foodborne pathogens in environmental samples challenges current understanding of the nature of foodborne pathogen contamination.

Direct Real-Time PCR with Ethidium Monoazide: A Method for the Rapid Detection of Viable Cronobacter sakazakii in Powdered Infant Formula

The novel loop-mediated isothermal amplification based confirmation methodology on the bacteria in Viable but Non-Culturable (VBNC) state

Improvement of methods for the detection of Gram-negative foodborne pathogens

Cooperation and competition between CRISPR- and omics-based technologies in foodborne pathogens detection: a state of the art review

MXene, owing to its high electrical conductivity, large specific surface area, and abundant surface functional groups, has been widely applied in the detection of foodborne pathogens. Therefore, it is necessary to review recent developments in the emerging material MXene for the detection and killing of foodborne pathogens, which is expected to facilitate the further development and utilization of MXene. This work comprehensively reviews advances in MXene applications for detecting and killing foodborne pathogens. Firstly, applications of MXene in electrochemical sensors, surface-enhanced Raman scattering (SERS), fluorescence platforms, and fluorescence–electrochemical dual-mode sensing systems are introduced. Subsequently, the sterilization mechanisms of MXene are described, followed by a detailed explanation of its practical applications in active food packaging, surface modification of food processing equipment, and instant sterilization techniques. Finally, conclusions, challenges, and future prospects in the area of MXene for the detection and killing of foodborne pathogens are discussed in depth. Significantly, this review uniquely summarizes applications of MXene in the detection and sterilization of foodborne pathogens, offering new perspectives on its use in food safety.

Reduced graphene oxide (rGO) has emerged as a promising nanomaterial for reliable detection of pathogenic bacteria due to its exceptional properties such as ultrahigh electron transfer ability, large surface to volume ratio, biocompatibility, and its unique interactions with DNA bases of the aptamer. In this study, rGO-azophloxine (AP) nanocomposite aptasensor was developed for a sensitive, rapid, and robust detection of foodborne pathogens. Besides providing an excellent conductive and soluble rGO nanocomposite, the AP dye also acts as an electroactive indicator for redox reactions. The interaction of the label-free single-stranded deoxyribonucleic acid (ssDNA) aptamer with the test organism, Salmonella enterica serovar Typhimurium (S. Typhimurium), was monitored by differential pulse voltammetry analysis, and this aptasensor showed high sensitivity and selectivity for whole-cell bacteria detection. Under optimum conditions, this aptasensor exhibited a linear range of detection from 108 to 101cfumL-1 with good linearity (R 2=0.98) and a detection limit of 101cfumL-1. Furthermore, the developed aptasensor was evaluated with non-Salmonella bacteria and artificially spiked chicken food sample with S. Typhimurium. The results demonstrated that the rGO-AP aptasensor possesses high potential to be adapted for the effective and rapid detection of a specific foodborne pathogen by an electrochemical approach. Graphical abstract Fabrication of graphene-based nanocomposite aptasensor for detection of foodborne pathogen.

The incidence of foodborne diseases has increased over the years and resulted in major public health problem globally. Foodborne pathogens can be found in various foods and it is important to detect foodborne pathogens to provide safe food supply and to prevent foodborne diseases. The conventional methods used to detect foodborne pathogen are time consuming and laborious. Hence, a variety of methods have been developed for rapid detection of foodborne pathogens as it is required in many food analyses. Rapid detection methods can be categorized into nucleic acid-based, biosensor-based and immunological-based methods. This review emphasizes on the principles and application of recent rapid methods for the detection of foodborne bacterial pathogens. Detection methods included are simple polymerase chain reaction (PCR), multiplex PCR, real-time PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) and oligonucleotide DNA microarray which classified as nucleic acid-based methods; optical, electrochemical and mass-based biosensors which classified as biosensor-based methods; enzyme-linked immunosorbent assay (ELISA) and lateral flow immunoassay which classified as immunological-based methods. In general, rapid detection methods are generally time-efficient, sensitive, specific and labor-saving. The developments of rapid detection methods are vital in prevention and treatment of foodborne diseases.

Diagnostic PCR: making internal amplification control mandatory.

Chapter 2 - Modern techniques and developments in the detection of foodborne pathogens

As food safety management further develops, microbiological testing will continue to play an important role in assessing whether Food Safety Objectives are achieved. However, traditional microbiological culture-based methods are limited, particularly in their ability to provide timely data. The present review discusses the reasons for the increasing interest in rapid methods, current developments in the field, the research needs, and the future trends. The advent of biotechnology has introduced new technologies that led to the emergence of rapid diagnostic methods and altered food testing practices. Rapid methods are comprised of many different detection technologies, including specialized enzyme substrates, antibodies and DNA, ranging from simple differential plating media to the use of sophisticated instruments. The use of non-invasive sampling techniques for live animals especially came into focus with the 1990s outbreak of bovine spongiform encephalopathy that was linked to the human outbreak of Creutzfeldt Jakob's Disease. Serology is still an important tool in preventing foodborne pathogens to enter the human food supply through meat and milk from animals. One of the primary uses of rapid methods is for fast screening of large number of samples, where most of them are expected to be test-negative, leading to faster product release for sale. This has been the main strength of rapid methods such as real-time Polymerase Chain Reaction (PCR). Enrichment PCR, where a primary culture broth is tested in PCR, is the most common approach in rapid testing. Recent reports show that it is possible both to enrich a sample and enumerate by pathogen-specific real-time PCR, if the enrichment time is short. This can be especially useful in situations where food producers ask for the level of pathogen in a contaminated product. Another key issue is automation, where the key drivers are miniaturization and multiple testing, which mean that not only one instrument is flexible enough to test for many pathogens but also many pathogens can be detected with one test. The review is mainly based on the author's scientific work that has contributed with the following new developments to this field: (i) serologic tests for large-scale screening, surveillance, or eradication programs, (ii) same-day detection of Salmonella that otherwise was considered as difficult to achieve, (iii) pathogen enumeration following a short log-phase enrichment, (iv) detection of foodborne pathogens in air samples, and finally (v) biotracing of pathogens based on mathematical modeling, even in the absence of isolate. Rapid methods are discussed in a broad global health perspective, international food supply, and for improvement of quantitative microbial risk assessments. The need for quantitative sample preparation techniques, culture-independent, metagenomic-based detection, online monitoring, a global validation infrastructure has been emphasized. The cost and ease of use of rapid assays remain challenging obstacles to surmount.

It is a public health imperative to have safe food and water across the population. Foodborne infections are one of the primary causes of sickness and mortality in both developed and developing countries. An estimated 100 million foodborne diseases and 120 000 foodborne illness-related fatalities occur each year in India. Several factors affect foodborne illness, such as improper farming methods, poor sanitary and hygienic conditions at all levels of the food supply chain, the lack of preventative measures in the food processing industry, the misuse of food additives, as well as improper storage and handling. In addition, chemical and microbiological combinations also play a key role in disease development. But recent disease outbreaks indicated that microbial pathogens played a major role in the development of foodborne diseases. Therefore, prompt, rapid, and accurate detection of high-risk food pathogens is extremely vital to warrant the safety of the food items. Conventional approaches for identifying foodborne pathogens are labor-intensive and cumbersome. As a result, a range of technologies for the rapid detection of foodborne bacterial pathogens have been developed. Presently, many methods are available for the instantaneous detection, identification, and monitoring of foodborne pathogens, such as nucleic acid-based methods, biosensor-based methods, and immunological-based methods. The goal of this review is to provide a complete evaluation of several existing and emerging strategies for detecting food-borne pathogens. Furthermore, this review outlines innovative methodologies and their uses in food testing, along with their existing limits and future possibilities in the detection of live pathogens in food.

Numerous techniques are employed for the detection of various types of pathogens in different foods. Rapid detection of foodborne pathogens is very important by using biosensors. The objectives of this review are to highlight the application of the biosensors in detecting foodborne pathogens, future trends of biosensors technology in foodborne pathogens detection, and limitations of biosensors in the food industry. Biosensors are analytical devices and one of the rapid detection methods that can combat certain limitations of conventional detection techniques, such as portability, time, cost, sensitivity, and others. Biosensors have many applications in different fields. Biosensors in the food industry are used for the detection and identification of foodborne pathogens. The uses of biosensors in food are increasing from day to day due to different factors. In the future, the latest generations, which are autonomous and nanomaterial-based biosensors will emerge. There is also a need to develop a biosensor that is easy to use and has a short detection time.

Foodborne pathogens affect human health negatively and are known to cause economic losses. Therefore, quick detection of foodborne pathogens and the implementation of measures to ensure their inactivation are of immense significance. Immunological, molecular, and cultural methods are frequently used in the detection of foodborne pathogens. High cost, prolonged analysis times, and the necessity of specialized personnel are some of the disadvantages of these methods. Biosensors are known as analytical devices. The use of biosensors is considered a new approach to quickly detect foodborne pathogens and their toxins. Biosensors, which are capable of converting biological, chemical, or biochemical signals into measurable electrical signals, are systems containing a biological detection material combined with a chemical or physical transducer. Different types of biosensor are being employed for detection of pathogenic bacteria. Biosensors are sensitive, fast, economical, reliable, and portable devices, and are used in many fields such as food safety, medicine, pharmacy, measurement of environmental pollution, and the military defense. Electrochemical and optical biosensors and piezoelectric immunosensors are among the most frequently used biosensors in the detection of foodborne pathogens. In this article, the principle components and requirements for an ideal biosensor, types, and their applications in food industry are summarized.

The detrimental impact of foodborne pathogens on human health makes food safety a major concern at all levels of production. Conventional methods to detect foodborne pathogens, such as live culture, high-performance liquid chromatography, and molecular techniques, are relatively tedious, time-consuming, laborious, and expensive, which hinders their use for on-site applications. Recurrent outbreaks of foodborne illness have heightened the demand for rapid and simple technologies for detection of foodborne pathogens. Recently, Lateral flow assays (LFA) have drawn attention because of their ability to detect pathogens rapidly, cheaply, and on-site. Here, we reviewed the latest developments in LFAs to detect various foodborne pathogens in food samples, giving special attention to how reporters and labels have improved LFA performance. We also discussed different approaches to improve LFA sensitivity and specificity. Most importantly, due to the lack of studies on LFAs for the detection of viral foodborne pathogens in food samples, we summarized our recent research on developing LFAs for the detection of viral foodborne pathogens. Finally, we highlighted the main challenges for further development of LFA platforms. In summary, with continuing improvements, LFAs may soon offer excellent performance at point-of-care that is competitive with laboratory techniques while retaining a rapid format.