Screening of gamma irradiated spices in Korea by using a microbiological method (DEFT/APC)

Irradiation can be used to control the microbiological spoilage and pathogen microorganisms of foods. Microbiological changes associated with food irradiation include the reduction or elimination of spoilage and pathogenic microorganisms, insect disinfestation and parasite disinfection. The effects on the microbial populations of irradiated foods have been used to develop detection methods for irradiated foods. The method used in this study was direct epifluorescent filter technique/aerobic plate count (DEFT/APC), which is based on the difference between DEFT counts and APC counts. The samples were imported spices and domestic spices produced in Korea. These samples were irradiated at 1.0, 3.0, 5.0, 7.0, and 10 kGy to reduce the spoilage organisms. Irradiation doses of 3.0 kGy or over eliminated viable microorganisms effectively, and the logDEFT/APC ratio gradually increased with dose increment in all the samples. It could be suggested that if the logDEFT/APC ratio is 2.5 or over for peppers in Korea, the samples can be suspected as irradiated at a dose level of at least 3.0 kGy. The DEFT/APC method could be used for screening for the irradiation treatment of spices produced in Korea.