From conventional to biosensor-based detection of Cryptosporidium spp. and Toxoplasma gondii in food and water: Implications for food and water safety.

Zoonotic food- and waterborne protozoan parasites (FWPPs) pose a significant global public health risk, causing substantial morbidity via contaminated fresh produce, water, and meat. Despite their notable impact, surveillance and detection technologies remain inadequate for high-priority protozoans such as Cryptosporidium spp. and Toxoplasma gondii, as current World Health Organization (WHO) and Food and Agriculture Organization (FAO) guidelines primarily focus on bacterial pathogens. This review evaluates the global burden of Cryptosporidium spp. and T. gondii, and highlights the limitations of conventional detection methods, justifying the forward-looking perspective on biosensors' applications in detecting protozoan parasites (PPs), and future strategies in this regard. The complex nature and varied transmission routes of these parasites, along with challenges such as culturing, sample preparation, and morphological similarities, complicate their detection by conventional methods like microscopy, serology, and molecular assays. Additionally, these limitations include time-intensive protocols, infrastructure requirements, cost, and lack of portability, which restrict their suitability for rapid, on-site detection. Recent advances in biosensor technology may offer rapid, sensitive, and accurate on-site detection of FWPPs, driving a paradigm shift toward a smart food safety system. This review highlights the potential of emerging biosensor technologies, especially electrochemical, optical, and piezoelectric (gravimetric) biosensors, for the detection of Cryptosporidium spp. and T. gondii in food and water. Integrating biosensors with nanotechnology, artificial intelligence, point-of-care systems and microfluidics to create portable, cost-effective biosensors may revolutionize food safety surveillance, mitigating the impact of FWPPs, and aligning with Hazard Analysis and Critical Control Points (HACCP) priorities to safeguard public health.