Dried chilli is one of the highly traded spices globally and is well-known for its natural flavour, colour, and unique pungent taste. It is rich in nutrients and has medicinal benefits. During the dehydration and storage process, the proliferation of unwanted microorganisms in dried chilli is unavoidable. Recently, the occurrence of toxigenic fungi and faecal coliforms has been widespread that can cause severe illness and even death. Therefore, sanitation treatment is highly required to decontaminate undesirable microorganisms. Among the common sanitation treatments applied, food irradiation is gaining attention worldwide because of concern for post-harvest loss, foodborne disease, and more stringent regulation in dried chilli trading. Irradiation can successfully preserve dried chilli from pathogenic bacteria with minimal disturbance to critical physical properties, such as pungency and colour. It can also save dried chilli from secondary pollution by storing it into final packing before radiation which helps in distribution to market promptly after treatment. Furthermore, radiation does not leave any chemical residues after the treatment, ensuring the quality and safety of the dried chilli. The efficiency of radiation depends mainly on the initial level of contamination and the persistence of the harmful microorganism. A low irradiation dose is sufficient for dried chili to reduce microbial load to an acceptable level and eliminate pathogens even though a minimum radiation dose of 10 kGy is required for complete sterilization. However, high dosage may affect the colour properties. Gamma radiation, X-ray, and electron beam radiation are the three approved radiation sources for dried chilli in most countries and proven effective for dried chilli preservation. Thus, this review paper highlights the microbial and physical quality properties in gamma radiated dried chillies.

The effects of gamma radiation up to 10 kGy and storage time (0 to 16 weeks) on microbial and physicochemical properties of dried Byadgi chili were investigated. After 2.5, 5.0, 7.5, and 10.0 kGy of radiation, the samples were kept at room temperature with the control sample (0 kGy) and analyzed at 0, 4, 8, 12, and 16 weeks. Microbial aspects including total aerobic count (TAC), E. Coli, coliform, yeast, and mold were tested, as were physicochemical characteristics such as moisture, water activity, surface color (L*, a*, b*, chroma, and hue), aflatoxin, capsaicin, and dihydrocapsaicin. As the radiation dose and storage period were increased, water activity rose in lockstep with moisture. Gamma radiation had no effect on the color of the surface up to 10 kGy, although it did not aid with the retention of the initial color value during storage. Mold growth was observed in the control, 2.5, 5.0, and 7.5 kGy radiated samples, but no aflatoxin was found. The increase in radiation dose and storage time had a negative effect on capsaicin and dihydrocapsaicin. TAC was also observed at the end of the storage time, despite radiation at 10.0 kGy successfully sterilizing dried Byadgi chili. The principal component analysis (PCA) biplot revealed two distinct groupings based on duration of storage times. Radiation at 10.0 kGy had an excellent response to the microbial profile, with only minimal changes in quality attributes after eight weeks of storage.