Traditional and modern storage methods for onion preservation: Integrating internet of things technologies for quality parameter monitoring and control

Onions (Allium cepa L.) represent a critical global food security crop, yet post-harvest losses of 25–40 % in developing nations severely compromise nutritional accessibility and farmer livelihoods. This systematic review critically evaluates traditional and modern storage technologies while assessing internet of things (IoT) integration potential for real-time quality monitoring and automated environmental control. Following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, comprehensive literature searches across Web of Science, Scopus, PubMed and IEEE Xplore databases (2000–2024) identified 847 potentially relevant publications. After applying rigorous inclusion criteria requiring quantitative performance data, peer-reviewed publication status and English language accessibility, 156 studies underwent detailed analysis. Traditional ambient storage methods including field curing, naturally ventilated structures and conventional godowns demonstrate economic accessibility advantages but experience storage losses of 15–40 % over 3–5 months due to uncontrolled temperature and humidity fluctuations that accelerate physiological deterioration and microbial proliferation. Modern refrigerated cold storage systems maintaining precise environmental conditions of 0–1 °C temperature and 65–70 % relative humidity achieve extended shelf life of 6–10 months with losses consistently below 5 %. However, substantial capital investment requirements of USD 400–800 per tonne storage capacity combined with technical operational expertise needs restrict adoption primarily to large-scale commercial operations. The IoT-enabled precision storage systems integrate distributed wireless sensor networks for continuous monitoring of temperature, relative humidity, carbon dioxide concentration and sprouting indices, coupled with automated actuator control optimising ventilation, refrigeration and humidity management. Techno-economic analyses indicate achievable loss reductions of 10–20 % with investment payback periods of 2–3 years, though these metrics exhibit substantial sensitivity to wholesale price volatility and regional electricity costs. Critical implementation barriers include inadequate rural telecommunications infrastructure affecting 58 % of agricultural facilities, insufficient technical support networks, sensor calibration drift in condensing environments and limited digital literacy. Hybrid retrofitting approaches combining traditional infrastructure with IoT monitoring and evaporative cooling demonstrate economic viability, achieving 15–30 % loss reduction at 70–85 % of full cold storage costs. Priority research directions include commercial-scale field validation across diverse agroclimatic zones, standardised interoperability framework development and farmer-centered participatory design approaches.