Table 2.

Recent advancement of biosensors as smart food traceability system.

Category	Advancement	Advantage	Future direction	References
Agriculture	Monitor dissolved oxygen in water	In-situ, continuous, and autonomous	Stable over long-term performance	[38]
	Detect antibiotics in soil	Simultaneous, easily parallelizable, cost-effective	Specifically measure the concentration of a particular tetracycline type	[39]
	Monitor soil contamination	Simple, reliable, safe, inexpensive, portable, highly responsive, ambient light blocked, temperature controlled, and water jacketed	Real time application in soil	[40, 41]
	Detect plant infections, abiotic stress, metabolic content, phytohormones, miRNAs, genetically modified (GM) plants	On-site, in-vivo, online, and fast detection and reproducibility	More research and development	[42, 43]
Food quality	Determine polyphenols	Easy sample preparation, selective and sensitive, reproducible, low cost, portable, wide linear range, and accurate with excellent limit of detection (LOD)	Simple optimization method to limit interference of electrodeposition of nanoparticles	[44]
	Assess antioxidant capacities	Sensitive and precise, fast response time, and ease of miniaturization	Integration of intelligent devices, functional material application and model diversification, and explicit mechanism	[45]
	Assess food authenticity and detect illegal food additives	Highly selective and sensitive, facile, robust, portable, cost effective, higher detectability, universal	Modification of nanoparticles with specific ligands to improve selectivity, simple sample pretreatment	[46, 47]
	Detect food freshness	Highly sensitive, low cost, robust, and portable	Increase rate of reusability with simple cleaning process	[48]
	Quantify ethanol in beverages	Simple, fast, and highly sensible with elevated stability and biocompatibility	Usage of nanomaterials to enhance sensibility and applied for monitoring fermentation stage	[49]
	Monitor survival and freshness of fish	Simple, rapid, and accurate	Longer lifespan, stable over environmental factors, multiple freshness marker measured, and low cost	[50]
Food safety	Detect allergens	sensitive, selective, low-cost, and time-efficient	Associations of different transducer systems and nanomaterials with novel immobilization methods	[51]
	Detect antibiotics	Simple, low price, rapid response, real-time, good selectivity and sensitivity, easy miniaturization	Improvement in electrode materials (e.g. improve electrical conductivity and catalytic activity, amplifies biorecognition events), usage of different kind of nanomaterials, development of aptamers and molecularly imprinted polymers (MIPs) for multi-target analysis	[52], 53]
	Detect pathogenic microorganisms	Rapid, real-time, easy to carry out, and less labor-intensive	More sensitive and specific portable biosensor for utilization on farms to detect pathogens of fresh produce surface	[54]
	Detect fungal and bacterial toxins	High specific affinity, good chemical stability, low cost, easy to synthesis and modification	Sunlight powered and self-powered biosensor, split-type PEC biosensors and integrating PEC biosensing with arrays, microfluidics and chips for high-throughput and automation analysis	[55]
	Detect chemical contaminants (e.g. heavy metals, pesticides)	Low cost, continuous, specific, real-time, rapid, multiple analysis	Lower production cost to promote commercialization, modular assembly for real-time POC analysis, incorporation with nanotechnology and CRISPR-Cas-based diagnosis	[56, 57]