INGENIEUR
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eye but can lead to accelerated deterioration and quality loss . By identifying early damage , it is possible to segregate the affected agricultural produce and prevent them from contaminating the rest . As advancements in thermal imaging technology continue to emerge , its integration into postharvest handling practices is likely to become increasingly prevalent , contributing to more sustainable and profitable agricultural supply chains .
Detection of Spoilage and Disease
The detection of spoilage and disease in agricultural produce is crucial for maintaining quality , reducing waste , and ensuring food safety . Conventional methods of detecting spoilage , such as visual inspections and microbiological testing , can be time-consuming , subjective , and often inadequate for early detection . Thermal imaging technology offers a promising alternative by adopting the principle that metabolic activity and microbial growth often produce heat , which can be detected as temperature variations on the surface of produce .
In this case , thermal imaging cameras detect infrared radiation emitted by objects by converting it into temperature readings . Spoilage and disease in fruits , vegetables , and other agricultural produce can cause localised temperature changes due to metabolic heat production from microbial activity or physiological responses . For instance , fungal infections like Penicillium in citrus fruits generate heat as they metabolise the fruit sugars , creating hot spots detectable by thermal cameras even before visible symptoms appear . Thermal imaging has been adopted for identifying the growth level of dry rot disease in potato tubers ( see Figure 1 ). Apart from that , thermal imaging has been effectively used in various studies and practical applications . These applications demonstrated the potential of thermal imaging to identify problems that are not visible to the naked eye .
Unlike microbiological sampling or chemical testing , thermal imaging does not require physical contact with the agricultural produce , reducing the risk of contamination and allowing for repeated monitoring . Thermal imaging offers immediate
Figure 1 : The thermal imaging system for the detection of dry rot disease in potato tuber . Courtesy : Farokhzad et al . ( 2024 ).
results by facilitating rapid decision-making in postharvest management . This imminence is crucial for large-scale operations where delays can lead to significant losses . Apart from that , high-resolution thermal cameras can scan large quantities of produce quickly , making it feasible for use in the detection of spoilage and disease in the field . In commercial settings , integrating thermal imaging into conveyor systems allows for the continuous monitoring of agricultural produce . Automated systems equipped with thermal cameras can identify and separate items that show signs of spoilage or disease , ensuring that only high-quality produce reaches the market . This integration enhances operational efficiency and product quality , thus reducing postharvest losses .
Ambient temperature and humidity can affect thermal readings . High ambient temperatures , for example , can mask the heat signatures of spoilage , leading to false negatives . Proper calibration and controlled environments are necessary to ensure accurate results . Thermal imaging can detect temperature anomalies but cannot identify the specific type of spoilage or pathogen . Complementary methods such as molecular diagnostics or microbiological assays are needed to pinpoint the exact cause of spoilage .
Thermal imaging represents a significant advancement in the detection of spoilage and disease in postharvest handling . Its ability to provide non-invasive , real-time monitoring on
10 VOL 99 JULY - SEPTEMBER 2024