Retroreflection-based sandwich type affinity sensing of isothermal gene amplification product for foodborne pathogen detection

Loop-mediated isothermal amplification (LAMP) is an outstanding method for molecular diagnostics, as the rapid, specific, and sensitive amplification of target genes is possible. However, it is necessary to measure fluorescence...

Evaluation of anhydrous processing and storage methods of the temperate bacteriophage ɸV10 for integration into foodborne pathogen detection methodologies

Due to the nascency of bacteriophage-based pathogen detection technologies, several practical hurdles stand in the way between providing promising proof-of-concept data and development of robust detection platforms. One such hurdle, and the focus of this work, is the development of methods for transitioning laboratory stocks of bacteriophage into functional, consistent, and shelf-stable delivery methods in commercial detection kits. Research described here was undertaken to evaluate two methods for their ability to store the bacteriophage ɸV10 at ambient temperature without aqueous storage solutions while limiting loss of viability. ɸV10 is a temperate bacteriophage which solely infects the zero-tolerance food adulterant Escherichia coli O157:H7 and has been genetically modified to generate a detectable phenotype in host cells. In order to integrate this reporter bacteriophage into food-borne pathogen detection methodologies, two methods of processing phage suspensions for long-term, ambient storage were evaluated: printing solutions onto pieces of dissolvable paper and lyophilizing suspensions with sucrose. Applying phage to dissolvable paper yielded key attributes to consider when addressing phage viability, however, optimized methodology still resulted in an approximate five-log reduction in titer of viable phage. Lyophilization of ɸV10 with various concentrations of the cryoprotectant molecule, sucrose, yielded losses of approximately 0.3-log after 120 days of storage at 23°C. Liquid storage buffer samples with and without sucrose saw a reduction of viable phage of at least 3.9-log in the same period. Additionally, the ability for ɸV10 to form lysogens in an E. coli O157:H7 host was not negatively affected by lyophilization. Drying ɸV10 at ambient temperature drastically reduces the viability of the phage. However, lyophilizing ɸV10 in the presence of sucrose is an effective method for dehydration and storage of the phage in ambient environmental conditions for an extended time lending to commercial application and integration into foodborne pathogen detection methodologies.

Current State of Biosensors Development and their Application in Foodborne Pathogen Detection

Foodborne disease outbreaks continue to be a major public health and food safety concern. Ensuring the safety of food prior to retail distribution by testing products promptly can protect consumers from foodborne diseases. F ast, sensitive, and accurate detection tools are in great demand. Therefore, various approaches have been explored in the past few years to find a more effective way to incorporate antibodies, oligonucleotides, phages, and mammalian cells as signal transducers and analyte recognition probes on biosensor platforms. The ultimate goal is to achieve high specificity and low detection limits (1-100 bacterial cells or pico-nanogram levels of toxins). Besides, advancement in mammalian cells and bacteriophage-based sensors led to their ability to detect not only low levels of pathogens but also to differentiate live from dead ones. Combining different biotechnology platforms enabled practical utility and application of biosensors in foodborne pathogen detection. However, further rigorous testing of biosensors from complex food matrices is needed to ensure their utility in point-of-care need and for outbreak investigations.

QCM Sensor Arrays, Electroanalytical Techniques and NIR Spectroscopy Coupled to Multivariate Analysis for Quality Assessment of Food Products, Raw Materials, Ingredients and Foodborne Pathogen Detection: Challenges and Breakthroughs

Quality checks, assessments, and the assurance of food products, raw materials, and food ingredients is critically important to ensure the safeguard of foods of high quality for safety and public health. Nevertheless, quality checks, assessments, and the assurance of food products along distribution and supply chains is impacted by various challenges. For instance, the development of portable, sensitive, low-cost, and robust instrumentation that is capable of real-time, accurate, and sensitive analysis, quality checks, assessments, and the assurance of food products in the field and/or in the production line in a food manufacturing industry is a major technological and analytical challenge. Other significant challenges include analytical method development, method validation strategies, and the non-availability of reference materials and/or standards for emerging food contaminants. The simplicity, portability, non-invasive, non-destructive properties, and low-cost of NIR spectrometers, make them appealing and desirable instruments of choice for rapid quality checks, assessments and assurances of food products, raw materials, and ingredients. This review article surveys literature and examines current challenges and breakthroughs in quality checks and the assessment of a variety of food products, raw materials, and ingredients. Specifically, recent technological innovations and notable advances in quartz crystal microbalances (QCM), electroanalytical techniques, and near infrared (NIR) spectroscopic instrument development in the quality assessment of selected food products, and the analysis of food raw materials and ingredients for foodborne pathogen detection between January 2019 and July 2020 are highlighted. In addition, chemometric approaches and multivariate analyses of spectral data for NIR instrumental calibration and sample analyses for quality assessments and assurances of selected food products and electrochemical methods for foodborne pathogen detection are discussed. Moreover, this review provides insight into the future trajectory of innovative technological developments in QCM, electroanalytical techniques, NIR spectroscopy, and multivariate analyses relating to general applications for the quality assessment of food products.