Foodborne pathogens, food adulterants, allergens, and toxic chemicals in food can cause major health hazards to humans and animals. Stringent quality control measures at all stages of food processing are required to ensure food safety. There is, therefore, a global need for affordable, reliable, and rapid tests that can be conducted at different process steps and processing sites, spanning the range from the sourcing of food to the end-product acquired by the consumer. Current laboratory-based food quality control tests are well established, but many are not suitable for rapid on-site investigations and are costly. Microfluidic paper analytical devices (μPADs) are a fast-growing field in medical diagnostics that can fill these gaps. In this review, we describe the latest developments in the applications of microfluidic paper analytic device (μPAD) technology in the food safety sector. State-of-the-art μPAD designs and fabrication methods, microfluidic assay principles, and various types of μPAD devices with food-specific applications are discussed. We have identified the prominent research and development trends and future directions for maximizing the value of microfluidic technology in the food sector and have highlighted key areas for improvement. We conclude that the μPAD technology is promising in food safety applications by using novel materials and improved methods to enhance the sensitivity and specificity of the assays, with low cost.

Metal nanoparticles enable sensitive detection in paper-based microfluidic devices via SERS, colorimetric, electrochemical, and chemiluminescent methods by utilizing plasmonic and catalytic effects.

We report on plasmonic sensors based on arrays of metallic bow tie nanoantennas with high sensitivity and an enhanced figure of merit. In the present sensing device, each gold nanoantenna is positioned on the upper surface of a SiO₂ nanopillar that is placed on a quartz substrate. The presence of the nanopillar significantly reduces the coupling of the enhanced electromagnetic field generated at the plasmon resonance to the substrate. The simulated results show that the sensitivity of the device to refractive index sensing is 612 nm/RIU, calculated by the resonance wavelength shift per refractive index unit due to the change in the ambient medium index, while the full width at half maximum is calculated at around 10 nm with a figure of merit of 61. The proposed sensor thus has a great potential for sensing and detection applications.