加工食品から簡便迅速にDNAを抽出することを目的としてシリカ膜を用いた新規DNA抽出法を開発した。本法は穀物を対象とするDNA抽出キットGM quicker 2を基盤とし、加工食品からのDNA抽出に最適化を図ったものである。試料の前処理にはプロテイナーゼK(20mg/ml)を20μl添加し、65℃で30分間処理する条件を採用した。また、より多くのDNAを回収する条件として、2Mの酢酸カリウム溶液(pH3.7)を(液状試料には)200μl、(乾燥試料には)400μl、及び8Mのグアニジン塩酸塩溶液を600μl抽出に用いることとした。次に、6種類の加工食品(きな粉、豆乳、味噌、トウモロコシ缶詰、スナック菓子、粉末コーンスープ)を用い、既存の4種類のDNA抽出法と新たに開発した方法の比較を行った。その結果、DNAの収量、純度及び操作性の各指標において、新たに開発した方法は従来法と同等かそれ以上の性能を有することが確認された。本研究で開発したDNA抽出法は、遺伝子組換え農産物や、アレルゲン、食中毒菌などを対象とする加工食品の遺伝子検査に広く活用されることが期待される。

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Rapid method combining microwave digestion and ICP-MS analysis was developed for the simultaneous determination of seven harmful elements (Cd, Pb, Ba, As, Hg, Cr and Ag) in food contact plastics, the former four elements are regulated by the Japanese Food Sanitation Law. After microwave digestion of 100mg of milled sample with HNO₃, digested solution was diluted and then applied to ICP-MS. The recoveries were mainly more than 80% using the standard and test solutions prepared by the equalized HNO₃ concentrations with the internal standards. This new method was also valid for analysis of Pb in polypropylene containing barium sulfate which showed very low recovery by dry ash method adopted in Japanese official method.

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A method for the determination of triethylamine and tributhlamine in polycarbonate products was developed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The sample was dissolved with dichloromethane, and the polymer was precipitated by addition of methanol. In order to avoid volatilization of triethylamine and tributylamine during evaporation of dichloromethane and methanol, 2% formic acid was added to the methanol mixture. After evaporation, triethylamine and tributylamine were determined by LC-MS/MS. Recoveries of triethylamine and tributylamine in polycarbonate products at the level of 1μg/g were 96,101% respectively, and the limits of quantification were 0.05μg/g in samples.

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Dapoxetine (1) and flibanserin (2) have pharmaceutical effects against premature ejaculation (PE) and hypoactive sexual desire disorder (HSDD), respectively. In international markets, these compounds have been reported as illegal additives in health foods for which tonic effects are implicitly indicated. Therefore, we performed LC-PDA-MS analysis in preparation for the distribution of illegal health foods containing these compounds in Japan. Compounds 1 and 2 were completely separated at r.t. 11.3 and 10.7 min, respectively, under the conditions described as the analytical method for udenafil by the Ministry of Health, Labour and Welfare, Japan. Their spectroscopic data (UV and MS) corresponded to the literature data. Subsequently, we added authentic dapoxetine and flibanserin to an extract of the food supplements with or without an ED treatment agent including sildenafil and tadarafil etc., and then these sample solutions were analyzed using the proposal method. As a result, each compound was completely separated on the UV and mass chromatograms. This study provides useful data for the surveillance of unapproved/unlicensed drugs in health food products.

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Many of Japanese consumers fear and avoid gene modified organisms (GMOs) although they don't know any technology, advantage and disadvantage of it. In addition, a lot of them don't know under 5% of contamination of GMOs to agricultural commodity is considered "unintended commingling" and allows to sign "Non-GMO" to products when they were treated under the identity preserved (IP) handling. In fact not exceeding 5% commingling of the Roundup Ready Soybeans (RRS) from soybean curds were reported in some areas around Japan. However there is not the evidence of the commingling of RRS to Soybean curds distributed at Nagano Prefecture. From these evidences, RRS content rates were examined almost Kinugoshi-tofu, soft and smooth soybean curds, which were sold at Matsumoto-city and its suburbs, Nagano pref., from May 2011 to April 2012. Genome DNA of soybean and RRS specific gene were extracted by silica-based membrane methods arranged for isolation DNA from tofu. RRS and internal control gene, Le1 were detected by realtime PCR-system. 101 samples of soybean curds were examined. The data showed 34 samples (33.7% of 101 samples) contained RRS. All of RRS contents were trace amount and lower than 5%, that was Consumer Affairs Agency's guideline.

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昭和60年より旧国立衛生試験所(現国立医薬品食品衛生研究所)食品部の室長として研究業務を行う事になったので、平成14年食品部長として退官までの20年弱の間、厚生労働省との関係で実施した研究業務の内、食品の安心と安全に関わる主要な部分の概要を紹介しようと思います。研究業務の順序としては、まず低沸点有機塩素系化合物の食品汚染、カビ毒の食品汚染、トリプトファン問題、ミネラルウォーターの異物混入問題、遺伝子組み換え食品の問題、ダイオキシンの食品汚染の問題、食物アレルギー原因物質の問題等に取り組みました。

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