The consumption of mycotoxins generated by fungi can have severe effects on the health of both humans and animals. These toxins can exist at dangerous levels in food products made from crops that have been infected with mycotoxinproducing fungi. Numerous methods have been developed for detecting mycotoxins in order to divert contaminated commodities from the food supply, but only allow for reactive, not preventive approaches. Furthermore, under favorable conditions toxin-producing fungi can continue to produce mycotoxins during storage and throughout the crop processing stages. By identifying mycotoxin-producing fungal species on crops or commodities, remediation such as fungicide application can be carried out, preventing the spread of infection and potential contamination of healthy crops, reducing waste of resources and ultimately improving food safety. Loop-mediated isothermal amplification (LAMP) has advantages for portable DNA detection due to its isothermal nature, resistance to matrix inhibitors, and the possibility of a long shelflife when reagents are dried onto a matrix. The developed microfluidic device allows for the homogenized wheat sample input after DNA extraction. The microfluidic device functions as a disposable cassette and can be heated by an independent, portable, isothermal heating device. The LAMP assay is combined with calcein for fluorescence detection. In this experiment, Fusarium graminearum, a trichothecene mycotoxin producer, was used as a proof-of-concept for the device with a LAMP assay targeting the gaoA gene, which codes for the enzyme galactose oxidase (GO), a unique enzyme produced by only a few other fungal species. The presence of Fusarium graminearum was detected in contaminated wheat samples utilizing the described methods, indicating the potential detection of mycotoxin-producing fungi. In the future, the device will be expanded to test for multiple mycotoxin-producing genes.
Accumulating evidence suggests that cytokine storm syndrome (CSS) induced by the SARS-CoV-2 may be the ultimate cause of acute respiratory distress syndrome (ARDS), resulting in severe outcomes of COVID-19 infection and potentially death. Elevated levels of serum interleukin 6 (IL-6) correlate with the occurrence of respiratory failure, ARDS, and adverse clinical outcomes in many COVID-19 patients. The currently available clinical cytokine tests are costly, time-consuming, and require skilled technicians to execute. There is an unmet need for rapid, affordable, robust, and sensitive tests for cytokine levels. Therefore, this study aimed to develop a cost-effective system for quantitative detection of cytokines that can be used in the point-of-care (POC) format within a few minutes of blood collection. Our approach combines detection based on laser-induced breakdown spectroscopy with a lateral flow immunoassay (LIBS-LFIA) to deliver a quantitative clinical analysis platform with multiplexing capability. Lanthanide-complexed polymers (LCPs) were selected as the labels to provide optimal quantitative performance when sensing signals from the test lines of LFIAs. For a prototype implementation and a proof-of-concept, we targeted IL-6 as it is one of the most critical pro-inflammatory cytokines. Our initial LIBS-LFIA biosensor achieved a limit of detection (LOD) of 0.2298 μg/mL of IL-6 within 15 minutes and further sensitivity increase is possible with optimization. Regardless, since high levels of IL-6 are reported for patients in crisis, this is more than adequate to identify patients with highly elevated cytokine levels. Our research provides evidence that rapid and accurate detection of cytokines for clinical diagnosis and prognosis of COVID-19 and other pathogenic infections using LIBS is highly feasible and compatible with the POC format.
Rapid detection and disinfection of microbial contamination is an ongoing concern across various food processing industries. Numerous methods exist for detection, including nucleic acid-based, fluorescence microscopy, and immunological-based tests. There is an emerging interest in using optical techniques to perform detection and disinfection simultaneously. This study reports on experimental results of energy density effects on disinfection of gram-negative organisms using a commercially available portable device. Three different gram-negative organisms were cultured and diluted over a four-log range. Samples of different concentrations were plated and exposed to UVC with increasing energy densities. A summary of the disinfection rate is presented. We identified an appropriate energy density condition that was required depending upon the concentration and type of microorganisms. The results showed that the tested portable device could serve be a valuable alternative for in-field screening and disinfection.
Fungal species such as Aspergillus, Fusarium and Alternaria can contaminate agricultural commodities in the field or during storage and produce mycotoxins. They usually pose threats to human and animal health and can result in significant economic loss. Specifically, Fusarium graminearum, the major causative agent of Fusarium head blight (FHB) of small cereals produces mycotoxins including deoxynivalenol, nivalenol, and zearalenone. Conventional detection methods are time-consuming, expensive and require large-scale instruments and skilled technicians. Furthermore, detection of the toxins in post-harvested grain is a process that can only be accomplished after the grain is harvested. Therefore, our goal was to develop a molecular point-of-detection (POD) platform which was sensitive and specific to detect low levels of toxin-producing fungi within agricultural products in the field and could also be used directly in food products. Herein, we investigated a rapid molecular POD assay called loop mediated isothermal amplification (LAMP) to detect low levels of genomic DNA extracted from Fusarium graminearum, which is often associated with toxicological potential and food safety issues. Both fluorescent and colorimetric LAMP assays were characterized and optimized to detect low-level of pathogens within 70 and 50 minutes respectively. In summary, LAMP offers an efficient assay format for rapid and specific nucleic acid-based detection of mycotoxins in-field use. Coupled with our custom-designed microchip, our platform provides a proof-of-principle to achieve low-cost and widespread foodborne pathogens testing at the POD which is highly desirable to keep analysis time and costs low, but more importantly be a field use application.
Due to its ease of sample preparation and rapid processing speed, laser-induced breakdown spectroscopy (LIBS) has emerged as a promising new technique for food analysis. Food adulteration detection is critical for fair trade and protecting customers from food fraud. As a result, there is a high demand for a rapid and portable detection method for authenticating and evaluating the safety of marketed food and beverage products. An increased prevalence of food fraud which frequently entails the substitution of inferior ingredients for high-quality products has necessitated the development of innovative measures for detecting and preventing fraud. In this report, we describe an authentication approach utilizing a custom designed benchtop LIBS system. We focused on high-value regional food products such as European alpine-style cheeses and Italian balsamic vinegars. Liquid samples were measured on paper without any pretreatment, and solid samples were ablated directly on the sample surface by LIBS. The pre-processed LIBS spectra were utilized for training and validating various classifiers for sample categorization and validation. The development of an elastic net (ENET) classification model is also reported in the study. In summary, our research highlighted the potential of the LIBS technique combined with chemometric methods for solid and liquid high-value food authenticity certification. The results show that LIBS enables rapid analysis and accurate food sample classification without the requirement for sample pretreatment.
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