Hyung-Wook Chung

ESR spectroscopy for detecting gamma-irradiated dried vegetables and estimating absorbed doses

In view of an increasing demand for food irradiation technology, the development of a reliable means of detection for the control of irradiated foods has become necessary. Various vegetable food materials (dried cabbage, carrot, chunggyungchae, garlic, onion, and green onion), which can be legally irradiated in Korea, were subjected to a detection study using ESR spectroscopy. Correlation coeAcients (R 2 ) between absorbed doses (2.5‐15 kGy) and their corresponding ESR signals were identified from ESR signals. Pre-established threshold values were successfully applied to the detection of 54 coded unknown samples of dried clean vegetables (chunggyungchae, Brassica camestris var. chinensis), both non-irradiated and irradiated. The ESR signals of irradiated chunggyungchae decreased over a longer storage time, however, even after 6 months of ambient storage, these signals were still distinguishable from those of non-irradiated samples. The most successful estimates of absorbed dose (5 and 8 kGy) were obtained immediately after irradiation using a quadratic fit with average values of 4.85 and 8.65 kGy being calculated. # 2000 Elsevier Science Ltd. All rights reserved.

Thermoluminescence detection of Korean traditional foods exposed to gamma and electron-beam irradiation

Abstract Thermoluminescence(TL) analysis was applied to detect irradiated Korean traditional condiments and soup mixes containing salt(NaCl). These food items, which are commercially irradiated in Korea, showed a consistently high correlation(R 2 ) between the absorbed doses and the corresponding TL responses. It was proved that table salt played a role as an in-built indicator in TL measurements and its concentration in test samples was proposed as a correction factor for varying conditions of TL measurements. Pre-established threshold values were successfully adopted to identify 167 coded samples of Ramen soup mixes, both non-irradiated and irradiated with gamma and electron-beam energy. The TL intensity of irradiated soup mixes decreased with the lapse of time, but was still distinguishable from that of the non-irradiated samples at the fourth month of ambient storage. Expected estimates of absorbed doses, 2.85 and 4.75 kGv were obtained using a quadratic equation with average values of 1.57 and 4.90 kGy, respectively.

Establishment of 22 Pesticide MRLs in Agricultural Products based on Risk Assessment

BACKGROUND: Food Sanitary Act establishes Maxi- mum Residue Limits (MRLs) of pesticides in food that are newly registered and used per each quarter, as stipulated by Agro-chemical Control Act. Current Food Code contains the MRLs for a total of 418 pesticides in 184 food types. METHODS AND RESULTS: National MRLs for pes- ticides have been established by based on scientific data of good agricultural practice, acceptable daily intake (ADI), food intake, average body weight and others. MRLs for pesticides are generally set under the principle that theoretical maximum daily intake (TMDI) are always below ADI. As results, 27 MRLs in agricultural products were newly proposed for 22 pesticides (fungicide: azoxy- strobin, fludioxonil, fluquinconazole, flusilazole, iprova- licarb, kresoxim-methyl, mandipropamid, metconazole, pyraclostrobin, tebuconazole, triflumizole, etc., Insecti- cide: dinotefuran, flubendiamide, indoxacarb, cyhalothrin, spinetoram, thiacloprid, thiamethoxam, metaflumizone, etc., Acaricide(miticide): cyenopyrafen, lufenuron) in 2010. CONCLUSION(s): There is no intake concerns for establishment of pesticide MRLs on foods in this time. Because the ratio of theoretical maximum daily intake (TMDI) are set below that of ADI.