畜禽類可食性內臟中鉛及鎘含量檢驗方法開發

Development of the Method for Lead and Cadmium in Edible Offal

動物內臟為優質之蛋白質來源，亦為營養素含量豐富的食物。但環境中重金屬可經由食物鏈累積至禽畜動物體內，特別是內臟，因此人類因食用動物內臟會有累積重金屬之風險。為瞭解禽畜類可食性內臟中鉛及鎘含量現況，本研究採集市售豬內臟、家禽類內臟及牛內臟等可食性內臟檢體，共計17件，經微波酸消化後，以感應耦合電漿質譜儀（Inductively Coupled Plasma Mass Spectrometry, ICP-MS）檢測，建立禽畜類可食性內臟之鉛及鎘含量檢驗方法。本方法取檢體加入濃硝酸，經微波消化器消化後，以ICP-MS進行分析。結果顯示，最佳微波消化條件為溫度240℃加熱30分鐘（升溫20分鐘，持溫10分鐘）；以ICP-MS分析時，質量數以鉛208及鎘114定量。本研究所建立鉛及鎘標準曲線之相關係數皆達0.999以上，定量極限均為0.01 ppm，符合牛、羊、豬及家禽可食性內臟重金屬衛生標準（鉛0.5 ppm）之需求。分別檢測英國之動物內臟品管物質（FASPAS-T07221QC）、美國之牛肝標準參考物質（NIST-1577c）與歐盟之豬腎標準參考物質（ERM-BB186），結果鉛及鎘之回收率分別為100.0－101.9％及94.7－104.3％。另分別添加鉛及鎘標準品於豬肝、豬心、豬腎、豬肚、豬肝連、豬大腸、豬小腸、雞心、雞胗及牛肚等樣品中，鉛及鎘之添加回收率分別介於86.2－129.7％及81.7－120.0％。17件市售產品檢測結果，1件豬腎檢體鎘含量為0.10mg／kg、1件雞肝檢體鎘含量為0.04mg／kg、及1件鴨肝檢體鉛及鎘含量分別為0.06及0.07mg／kg，符合衛生福利部107年5月8日發布訂定之「食品中污染物質及毒素衛生標準」，其餘檢體則皆未檢出。 Offal is a good source of protein, and is very nutritious. Heavy metals may accumulate in offal through the food chain. This study aimed on the investigation of lead (Pb) and cadmium (Cd) levels in offal of poultry and livestock. Eleven samples including liver, heart, kidney, stomach, liver even, intestine, and small intestine from pig, heart and gizzards from chicken, and tripe from cattle were collected. The samples were prepared by microwave digestion and analyzed by inductively coupled plasma mass spectrometer (ICP-MS) to establish a testing method for Pb and Cd in offal of cattle, sheep, pig and poultry. Sample was accurately weighted 0.5 g into a digestion vessel, then 6 mL of concentrated nitric acid (70%) was added. The vessel was digested by microwave-digester, and then the prepared sample extract was analyzed by ICP-MS. The results showed that the best condition of microwave digestion was at 240 oC for 30 min (heating for 20 min, and holding for 10 min). The detecting m/z values for Pb and Cd were at m/z 208 and 114, respectively. The determination coefficients of calibration curves for Pb and Cd were both above 0.999. The limits of quantification for Pb and Cd were both 0.01 ppm. The recoveries of Pb and Cd in standard reference materials of offal from United Kingdom (FAPAST07221QC), bovine liver from America (NIST-1577c), and pig kidney made by EU (ERM-BB186) were 100.0 - 101.9% and 94.7 - 104.3%, respectively. Standards of Pb and Cd spiked in liver, heart, kidney, stomach, liver even, intestine, small intestine of pig, and heart, gizzards of chicken, and tripe of cattle showed recoveries 86.2% - 129.7% for Pb and 81.7% - 120.0% for Cd. A total of 17 commercial samples purchased from markets were surveyed. The results showed one pig kidney sample and one chicken liver sample were found containing 0.01 mg/kg of Cd and 0.04 mg/kg of Cd, respectively. A duck liver sample was found containing 0.06 mg/kg of Pb and 0.07 mg/kg of Cd. For the other 14 samples Pb and Cd were not detected.