Microfluidic paper-based analytical devices for food spoilage detection: emerging trends and future directions.

Food spoilage poses a global challenge with far-reaching consequences for public health, economic stability, and environmental sustainability. Conventional analytical methods for spoilage detection though accurate are often cost-prohibitive, labor-intensive, and unsuitable for real-time or field-based monitoring. Microfluidic paper-based analytical devices (μPADs) have emerged as a transformative technology offering rapid, portable, and cost-effective solutions for food quality assessment. This review critically examines the principles, fabrication methods, and detection mechanisms underlying μPADs, with a focus on their applications in monitoring spoilage-related biomarkers such as volatile nitrogenous compounds and biogenic amines. We highlight recent advances, including the integration of μPADs with different mechanisms such as colorimetry, fluorescence, wireless sensor, electrochemistry, electrochemiluminescence, and Surface-Enhanced Raman Spectroscopy (SERS). Furthermore, emerging trends such as nanotechnology, smartphone-enabled analysis, and machine learning-enhanced diagnostics are discussed in the context of real-time data acquisition and decision-making. Key limitations such as reproducibility, sensitivity, and regulatory barriers are addressed alongside prospective solutions. This comprehensive overview underscores the immense potential of μPADs to revolutionize food safety monitoring, particularly in decentralized and resource-limited environments.