In this study, we examined 78 powdered spice products for wheat contamination, using enzyme-linked immunosorbent assay (ELISA) to detect wheat proteins and polymerase chain reaction (PCR) to detect wheat DNA, as notified by the Japanese Ministry of Health, Labour and Welfare. Wheat protein was detected in 22 of the 78 samples, and wheat DNA was detected in 2 of these 22 samples. In addition, to ascertain the influence of PCR inhibitors, we screened the 22 samples for plant DNA. Plant DNA was not detected in 11 of the 22 samples. Therefore, we assumed that polysaccharides and/or phenolic compounds in the spice samples were responsible for inhibiting the PCR amplifications. Subsequently, using a modified PCR procedure, Ampdirect® plus, plant DNA was detected in all 22 samples, while wheat DNA was detected in 15 samples. These results suggest that commercial powdered spice products are contaminated with wheat. Ampdirect® plus can overcome the probable PCR inhibition, which is caused by the presence of other contaminants in the extracted DNA solution, and can easily be applied in food testing. Therefore, this method can be used to detect the presence of wheat and other allergens in processed food.

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A simple, rapid, and precise method for the determination of cyclopiazonic acid (CPA) in liquid seasoning was developed, which uses liquid chromatography with ultraviolet and photodiode array detection LC/UV(PDA) and liquid chromatography with time-of-flight mass spectrometry (LC/TOF-MS). CPA in liquid seasoning was subjected to ethyl acetate extraction, and solid-phase extraction using Oasis® HLB. LC/UV(PDA) was used for qualitative and quantitative analysis, and LC/TOF-MS was used as the confirmatory method. The limit of detection (S/N = 3) and the limit of quantification (S/N > 10) of CPA in LC/UV(PDA) were 0.01 μg/mL and 0.03 μg/mL, respectively. Standard materials were prepared for quality control samples (a low concentration of 0.2 μg/mL and a high concentration of 2.0 μg/mL), and internal quality control was performed. As a result, the trueness of the low concentration sample and the high concentration samples was 80.3% and 81.6%, respectively. The relative standard deviation (RSD) of repeatability was 5.3% or less, whereas that of intermediate precision was less than 10.1%. The results suggest that the developed method is useful for the determination of CPA in liquid seasoning.

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2-(5-ベンジル-3,6-ジオキソピペラジン-2-イル)酢酸(DKP)はアスパルテーム(APM)の製造時に副成される分解生成物の1つである。FAO/WHO合同食品添加物専門家会議(JECFA)、米国、EU、日本などでは、アスパルテーム中のDKP含量は1.5%以下との純度規定が設定されている。この規定への適合性を確認するための試験法として、JECFAや日本におけるAPM規格では、パックドカラムを用いたGC法が採用されているが、誘導体化などの前処理が煩雑なことやAPM中の夾雑成分の影響により、正確な定量が困難なケースが多い。本研究では米国食品化学物質規格集(FCC)のHPLC法を参考に、APM中のDKP分析における粒子径5μmのカラムを用いたHPLC法を確立し、その性能を評価した。添加回収試験(n=5)では、検討した2点の濃度におけるDKPの回収率は99.1%以上、RSDは0.4%であり、真度(回収率)、併行精度は良好であった。また、本法のDKPの定量下限(S/N=10)は、APMに対して0.002wt%、検出限界(S/N=3)は0.0005wt%であった。さらに、10種のAPM製品中のDKPの分析を行ったところ、本法及びFCC法のデータに有意な差は認められず、本法は、FCC法と同程度に正確なAPM中のDKP含量を算出できることが明らかとなった。以上より、本法は迅速、簡便なAPM中のDKP分析法として有用と考えられた。

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The effect of mung bean tripsin inhibitor (MBTI) on "himodori" kamaboko was analyzed by rheological and histological methods. Normal and himodori kamaboko were prepared from surimi of lizardfish (Saurida wanieso) by two step heating: preheating at 40℃ for 30, 120 min (normal) or 60℃ for 30, 60, 90, 120 min (himodori), and then 90℃ for 30 min. MBTI and E-64 were added in surimi before heating, respectively. Decreased breaking strength caused by himodori was improved by the addition of MBTI or E-64 even in long preheating time. Although himodori kamaboko showed the disturbed structure, its structure was recovered by treatment with MBTI at intermediate structural levels between normal and himodori kamaboko in light microscope. The electron micrographs showed an equal distribution of black and gray areas in the normal kamaboko. Although the addition of E-64 showed particle aggregation and unstained area as found in himodori kamaboko, MBTI failed to detect these phenomena. These results suggest that the addition of MBTI during making procedure may inhibit himodori occurrence.

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Daily intakes of food additives such as colors, preservatives, sweeteners and food manufacturing agents for children (1-6 years) in Japan were estimated using market basket method. A list of daily consumption of processed foods was prepared based on the National Nutrition Survey (2001-2002) and National Health and Nutrition Survey (2003). The food additives with the highest daily intake was orthophosphoric acid (9.4 mg/kg bw/day, expressed as phosphorus), followed by condensed phosphoric acid (0.76 mg/kg bw/day, expressed as phosphorus), and propylene glycol (0.47 mg/kg bw/day). Acceptable daily intake (ADI) and maximum tolerable daily intake (MTDI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) or Food Safety Commission of Japan were compared with the estimated daily intake of food additives in children. The ratio to ADI of the colors, preservatives, sweeteners and propylene glycol were 0〜1.9%. The ratio to the MTDI of phosphorus compounds was 15%.

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Daily intakes of food additives such as colors, preservatives, sweeteners and food manufacturing agents for children (1-6 years) in Japan were estimated using market basket method in 2014. A list of daily consumption of processed foods was prepared based on the special survey study (2011). The food additives with the highest daily intake was orthophosphoric acid (11 mg/kg bw/day, expressed as phosphorus), followed by condensed phosphoric acid (1.0 mg/kg bw/day, expressed as phosphorus), and propylene glycol (0.73 mg/kg bw/day). The estimated daily intake of food additives in children was compared with acceptable daily intake (ADI) and maximum tolerable daily intake (MTDI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) or Food Safety Commission of Japan. The ratio of the estimated daily intake to ADI for the colors, preservatives, sweeteners and propylene glycol were 0-2.9%. The ratio to the estimated daily intake to MTDI for phosphorus compounds was 18%.

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Total plate count, Escherichia coli or coliform bacteria on the surface of dried horse mackerel produced by cold-air or hot-air drying were tested. These organisms on the surface of dried-horse mackerel available on the market were considerably more than those of the fish produced by cold-air or hot-air drying. Twenty minutes soak in 1%NaCl and reduction of water activity by cold-air drying of the fish contributed to repress these bacteria. These results suggested that a strict hygienic management in preservation, transport and over-the-counter is required.

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In order to evaluate the applicability of combustion method to the measurement of maturity index of cheese, the method was compared with the Kjeldahl method that had been applied to the test. Soluble and total nitrogen content in seven kinds of cheeses with different maturity and physical property were determined by each method. The resulting nitrogen content and maturity index calculated from the both content of nitrogen were analyzed statistically. Repeatability and intermediate precision of soluble nitrogen by the combustion method are somewhat lower those of Kjeldahl method. Significant differences (P < 0.05) were observed between mean values of soluble nitrogen content by the two methods in some samples. However, the maturity indexes of each method agreed well in all samples, and the coefficient of correlation between the indexes by the two methods was over 0.999, suggesting that the combustion method is applicable to the measurement of maturity index of cheese as an alternative to Kjeldahl method.

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