The activity concentrations of naturally occurring radionuclides²²⁶Ra,²³²Th, and⁴⁰K were determined in 30 agricultural and virgin soil samples randomly collected from Kedah, north of Malaysia, at a fertile soil depth of 0–30 cm. Gamma-ray spectrometry was applied using high-purity germanium (HPGe) gamma-ray detector and a PC-based MCA. The mean radioactivity concentrations of²²⁶Ra,²³²Th, and⁴⁰K were found to be 102.08 ± 3.96, 133.96 ± 2.92, and 325.87 ± 9.83 Bq kg⁻¹, respectively, in agricultural soils and 65.24 ± 2.00, 83.39 ± 2.27, and 136.98 ± 9.76 Bq kg⁻¹, respectively, in virgin soils. The radioactivity concentrations in agricultural soils are higher than those in virgin soils and compared with those reported in other countries. The mean values of radium equivalent activity (Raeq), absorbed dose ratesD(nGy h⁻¹), annual effective dose equivalent, and external hazard index (Hex) are 458.785 Bq kg⁻¹, 141.62 nGy h⁻¹, and 0.169 mSv y⁻¹, respectively, in agricultural soils and 214.293 Bq kg⁻¹, 87.47 nGy h⁻¹, and 0.106 mSv y⁻¹, respectively, in virgin soils, with averageHexof 0.525. Results were discussed and compared with those reported in similar studies and with internationally recommended values.

ZnO nanowhiskers were used for photodecomposition of methylene blue in aqueous solution under UV irradiation. The rate of methylene blue degradation increased linearly with time of UV irradiation. 54% of degradation rate was observed when the ZnO nanowhiskers were used as photocatalysts for methylene blue degradation for 80 min under UV irradiation. The decoration of p-type NiO nanoparticles on n-type ZnO nanowhiskers significantly enhanced photocatalytic activity and reached 72% degradation rate of methylene blue by using the same method. NiO-decorated ZnO was recycled for second test and shows 66% degradation from maximal peak of methylene blue within the same period. The increment of photocatalytic activity of NiO-decorated ZnO nanowhiskers was explained by the extension of the electron depletion layer due to the formation of nanoscale p-n junctions between p-type NiO and n-type ZnO. Hence, these products provide new alternative proficient photocatalysts for wastewater treatment.

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.