감귤 및 참다래의 저장 중 농약 잔류량 변화 연구

Abstract

This study was intended to determine residual pattern of a total of eight kinds of pesticides, including three organophosphorus insecticides, two organochlorine acaricides, and three dicarboximide fungicides during storage period after harvest of citrus and kiwi fruits, to provide basic data of safety control for agricultural products under storage and to examine practical use of agricultural products in which pesticide residue is above MRL (maximum residue limit). Ⅰ. Recovery test of pesticide standards Recovery test of pesticide standards was conducted to verify the validity of the analytical method applied to this study. In citrus fruit, the recovery of pesticides was ranged from 86.3 to 102.2%, CV (coefficient of variation) was ranged from 3.4 to 7.5%, and LOD (limit of detection) and LOQ (limit of quantitation) were 0.0004 ～ 0.007 mg/kg and 0.0013 ～ 0.0231 mg/kg, respectively. In kiwi fruit, the recovery of pesticide standards was 95.1 ～ 108.2% and CV was 3.4 ～ 9.4%. The LOD and LOQ of standards were 0.0006～0.006 mg/kg and 0.0019～0.0198 mg/kg, respectively. Ⅱ. Biological half-life of eight pesticides in citrus and kiwi fruits The biological half-life of organochlorine acaricides such as dicofol, tetradifon etc. in agricultural products was the shortest 61.9 days and the longest 70.0 days at 4℃, and the shortest 35.0 days and the longest 42.8 days at 20℃. That of organophosphorus insecticides such as fenitrothion, methidathion, EPN etc. was the shortest 35.0 days and the longest 43.9 days at 4℃ and the shortest 16.0 days and the longest 22.6 days at 20℃. That of dicarboximide fungicides such as vinclozoline, iprodione, procymidone etc. was the shortest 39.4 days and the longest 44.1 days at 4℃ and the shortest 15.3 days and the longest 23.7 days at 20℃, and is similar with organophosphorus insecticides. Altogether, the biological half-life of pesticides during storage at 20℃ was shorter than that at 4℃. The biological half-lives of EPN, fenitrothion, methidathion, dicofol, tetradifon, iprodione, procymidone, and vinclozolin in citrus fruit treated at low and high concentrations during storage period at 4℃ were 38.3 and 38.1 days, 35.0 and 36.7 days, 39.6 and 43.9 days, 70.0 and 61.9 days, 68.6 and 63.6 days, 40.8 and 39.4 days, 39.8 and 40.8 days, and 43.3 and 40.8 days, respectively. In citrus fruit during storage period at 20℃, half-lives of EPN, fenitrothion, methidathion, dicofol, tetradifon, iprodione, procymidone, and vinclozolin according to the level of treated concentration were 18.5 and 18.8 days, 16.3 and 19.2 days, 16.0 and 22.2 days, 38.5 and 34.1 days, 35.0 and 42.8 days, 17.7 and 15.3 days, 22.4 and 23.0 days, and 22.1 and 23.7 days at low and high concentrations, respectively. The biological half-lives of EPN, fenitrothion, methidathion, dicofol, tetradifon, iprodione, procymidone, and vinclozolin in kiwi fruit treated at low and high concentrations during storage period at 4℃ were 37.5 and 40.5 days, 38.5 and 36.1 days, 40.5 and 40.8 days, 64.8 and 65.4 days, 66.6 and 64.8 days, 43.1 and 44.1 days, 40.3 and 39.4 days, and 43.1 and 42.5 days, respectively. In kiwi fruit during storage period at 20℃, half-lives of EPN, fenitrothion, methidathion, dicofol, tetradifon, iprodione, procymidone, and vinclozolin according to the level of treated concentration were 20.3 and 19.8 days, 17.9 and 22.6 days, 19.8 and 22.1 days, 40.1 and 42.0 days, 37.3 and 44.1 days, 19.0 and 17.4 days, 22.9 and 21.1 days, and 23.7 and 23.5 days at low and high concentrations, respectively. Ⅲ. Residual pattern of pesticides in different parts of citrus and kiwi fruits A citrus fruit is composed of peel 25.6% and pulp 74.4%, and a kiwi fruit is composed of peel 23.2% and pulp 76.8%. Residual ratio (%) of pesticides in the peel of citrus and kiwi fruits was estimated by following equation; amount of pesticide residues in whole (mg/kg)/amount of pesticide residue in peel (mg/kg) × peel ratio × 100. Residual ratio of pesticides in the peel of citrus and kiwi fruits were 92.4 ～ 101.0% and 91.0 ～ 99.8% of total residue, respectively. All of eight pesticides remained over 91.1% in the peel of citrus and kiwi fruits. Therefore, it is concluded that if we find an effective peeling technique, the use of raw agricultural commodities, in which pesticide residue is about ten times higher than MRL, for the purpose of processed food of citrus and kiwi fruits is no problem for the safety. Ⅳ. Changes of weight during storage of citrus and kiwi fruits Reduction rates of weight per day during storage of citrus and kiwi fruits were 0.44 and 0.26% at 20℃, and 0.16 and 0.10% at 4℃, respectively. Reduction rate of weight in citrus fruit was higher than that in kiwi fruit and that in fruits during storage at 20℃ was twice or much higher than that at 4℃. Ⅴ. Suggestion for safety control of citrus and kiwi fruits under storage Absolute values of a regression coefficient in regression equations of EPN, fenitrothion, methidathion, iprodione, dicofol, tetradifon, procymidone and vinclozolin were 0.0171, 0.0160, 0.0158, 0.0161, 0.0099, 0.0101, 0.0170, and 0.0160, respectively. Safety control of citrus and kiwi fruits under storage is as following. 1st stage: "The day of market entry after making sure of safety" of fruits is determined from "generating equation of field tolerance of pesticides" with regression coefficient of eight pesticides. 2nd stage: "The day of market entry after making sure of safety" of fruits is provided to determine harvest or market entry. 3rd stage: If "The day of market entry after making sure of safety" is too long, check possibility of use for processing food.