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Natural toxins, mainly small molecules, are a category of chemical hazards in agri-food systems that pose threats to both public health and food security. Current standard methods for monitoring these toxins, predominantly based on liquid chromatography-mass spectrometry, are costly, labor-intensive, and complex. This study presents the development of a novel microfluidic optical aptasensor for rapid detection of small molecules based on analyte-tuned growth of gold nanoseeds combined with machine learning-enhanced spectrum analysis. We discovered and optimized a previously unreported growth pattern of aptamer-coated nanoparticles in the presence of different concentrations of analyte, enabling the detection of a major mycotoxin in food. The entire analysis was miniaturized on a customized microfluidic platform, allowing for automated spectral acquisition with precise liquid manipulation. A machine learning model, based on random forest with feature engineering, was developed and evaluated for spectrum analysis, significantly enhancing the prediction of mycotoxin concentrations. This approach extended the detection limit determined by the conventional method (∼72 ppb with high variation) to a wider range of 10 ppb to 100 ppm with high accuracy (overall mean absolute percentage error of 5.7%). The developed analytical tool provides a promising solution for detecting small molecules and monitoring chemical hazards in agri-food systems and the environment.

The food industry is increasingly focused on maintaining the quality and safety of food products as consumers are becoming more health conscious and seeking fresh, minimally processed foods. However, deterioration and spoilage caused by foodborne pathogens continue to pose significant challenges, leading to decreased shelf life and quality. To overcome this issue, the food industry and researchers are exploring new approaches to prevent microbial growth in food, while preserving its nutritional value and safety. Active packaging, including antimicrobial packaging, has gained considerable attention among current food packaging methods owing to the wide range of materials used, application methods, and their ability to protect various food products. Both direct and indirect methods can be used to improve food safety and quality by incorporating antimicrobial compounds into the food packaging materials. This comprehensive review focuses on natural and synthetic antimicrobial substances and polymer-based films, and their mechanisms and applications in packaging systems. The properties of these materials are compared, and the persistent challenges in the field of active packaging are emphasized. Specifically, there is a need to achieve the controlled release of antimicrobial agents and develop active packaging materials that possess the necessary mechanical and barrier properties, as well as other characteristics essential for ensuring food protection and safety, particularly bio-based packaging materials.

Mycotoxins are secondary metabolites of certain moulds, prevalent in 60-80% of food crops and many processed products but challenging to eliminate. Consuming mycotoxin-contaminated food and feed can lead to various adverse effects on humans and livestock. Therefore, testing mycotoxin residue levels is critical to ensure food safety. Gold standard analytical methods rely on liquid chromatography coupled with optical detectors or mass spectrometers, which are high-cost with limited capacity. This study reported the successful development of a microfluidic "lab-on-a-chip" device to enrich and detect zearalenone in food samples based on the fluorescence quenching effect of quantum dots and selective affinity of molecularly imprinted polymers (MIPs). The dummy template and functional polymer were synthesized and characterized, and the detailed microfluidic chip design and optimization of the flow conditions in the enrichment module were discussed. The device achieved an enrichment factor of 9.6 (±0.5) in 10 min to quantify zearalenone spiked in food with high recoveries (91-105%) at 1-10 mg kg -1 , covering the concerned residue levels in the regulations. Each sample-to-answer test took only 20 min, involving 3 min of manual operation and no advanced equipment. This microfluidic device was mostly reusable, with a replaceable detection module compatible with fluorescence measurement using a handheld fluorometer. To our best knowledge, the reported device was the first application of an MIP-based microfluidic sensor for detecting mycotoxin in real food samples, providing a novel, rapid, portable, and cost-effective tool for monitoring mycotoxin contamination for food safety and security.