Korea is highly dependent on the Chinese grain market and imports more than 170,000 tons of Chinese rice every year because of its comparatively low price than domestic commodity. In addition, demand for cheese grew rapidly due to the westernization of Korean food culture. In particular, more than 6,000 tons of American cheddar cheese were imported last year. Large-eyed herring is widely used for soup, but catches are steadily decreasing in the country, and so Vietnamese large-eyed herring are mainly distributed in the market. To control major agricultural pests, chemical crop protection agents are being implemented to prevent the propagation of insect pests that is increasing day by day due to the development of trade. However, there is a need for an alternative method to replace these chemical agents. Electron beam is used as a physical method to replace chemical control measures. Milk pasteurization has been advocated to prevent food-borne diseases associated with dairy products. But it is not an absolute safeguard, considering the possibility of failures or post-process mishandling. A previous study described irradiation as a perfectly effective food processing technology that offers the consumer with safe food products. However, the application of irradiation technology to dairy products has been hindered by the formation of byproducts resulting in off-odor and other off-characteristics in the irradiated product. In the case of dried fish, exposure to the atmosphere during processing and storage is likely to result in microbial contamination, and hence spoilage control by sterilization treatment is required. Since the electron beam is generated only by electric energy, there is no fear of residual radiation. The treatment time is short, and irradiation dose can be controlled easily, so that rapid surface treatment is possible. Electron beam is an eco-friendly technology that does not generate harmful substances and has been used in various fields due to its wide application area.
Irradiation can affect the odor profile of food samples based on the applied irradiation dose. The electronic nose (E-nose) system has potential application as a quick screening technique by comparing odor patterns at different irradiation doses. The application of E-nose was reported for irradiated tomatoes and red peppers. Other studies also characterized the irradiation status of anchovy sauce and fresh mushrooms, in which distinct odor patterns were observed from principal component analysis.
In this study, DEFT / APC method measures the number of microorganisms before and after irradiation to confirm any pre-sterilization treatment performed on the samples. Potential E-sensing techniques such as E-nose and E-tongue were applied as screening methods to distinguish the irradiation status of rice, cheddar cheese and large-eyed herring and the results were compared. After the application of E-sensing techniques, PSL analysis was performed to screen the irradiated samples based on the principle of light stimulation on minerals exposed to radiation. In addition, TL analysis based on the thermoluminescence properties of mixed minerals and ESR analysis for measuring free radical concentrations were applied as verification methods.