Aluminum is the third most abundant element in the earth’s crust and is widely used by humans including aluminum kitchen utensils and food packages. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) revised the provisional tolerable weekly intake (PTWI) for aluminum to 2 mg/kg body weight/week in 2011. The estimated range of mean dietary aluminum intake was 2-19 mg/person/day based on the literature. Aluminum kitchen utensils and food packages have the possibility to release aluminum into foods during cooking or storage, though the estimated aluminum intakes from them were reported very few. Therefore, Japanese aluminum intake was estimated based on our test results and Japanese food consumption data. The estimated aluminum intake from aluminum kitchen utensils and food packages was the highest for an adult per person, however, it was the highest for a child based on body weight. They ranged from 0.277-0.570 mg/person/day (0.06-0.12 mg/kg bw/week) on average and 0.677-1.333 mg/person/day (0.15-0.29 mg/kg bw/week) at a maximum. All of these results were sufficiently lower than the PTWI.

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Plant genetic engineering research has been used to confer metabolic pathways to fortify nutritional traits of crops. In these metabolically engineered crops, endogenous metabolic status should be inevitably influenced by the newly designed and introduced enzymatic steps with the aid of metabolic genes from other organisms. Here, we report metabolomic and proteomic comparisons between genetically modified (GM) high astaxanthin-producing lettuce (Lactuca sativa L.) that was generated with chloroplast transformation and its parental cultivar, together with commercial lettuce varieties as controls. It was demonstrated that the higher adenine levels in the GM lettuce samples were the only difference consistently observed between the GM and control lettuce samples. In addition, no significant differences were observed in the levels of nitrate-nitrogen and the allergenic protein Lac s 1. These results indicate that the endogenous metabolic status of lettuce is not noticeably modified by genetic engineering of the high astaxanthin-producing trait.

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An analytical method that uses LC-MS/MS was developed for the analysis of clenbuterol residue in pork muscle and processed pork food. The method was evaluated by conducting recovery tests according to the guidelines for validation of analytical methods by the Ministry of Health, Labour and Welfare of Japan. Samples were initially extracted with acetonitrile, anhydrous sodium sulfate, and sodium chloride. The extracts were subjected to dispersive solid-phase extraction (dSPE) based on C18 substrate and PSA cartridge column SPE. PSA effectively removed residual fatty acids and other interferences remaining in the extracts. Clenbuterol in the purified solution was determined quantitatively using LC-MS/MS. The recoveries of clenbuterol fortified at 0.05 ng/g in pork muscle and processed pork food were examined. For pork muscle and processed pork food measured by the matrix calibration curve method, accuracy (trueness) was 93.4% and 92.4%, repeatability was 3.0% for both, and within-laboratory reproducibility was 8.4% and 13.2%, respectively. For pork muscle and processed pork food measured by the internal standard method, accuracy (trueness) was 100.1% and 97.2%, repeatability was 5.1% and 2.8%, and within-laboratory reproducibility was 5.7% and 3.7%, respectively. These results indicate that both the matrix calibration curve method and the internal standard method meet the target values stated in the guidelines. Whereas the analytical method developed in this study is adequate for measuring current regulation levels of residues, in the examination of various types of processed food, such as processed pork food that requires different matrices, quantification by the internal standard method is likely to be more practical and desirable.

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Tienchi ginseng tea (TGT) extract was prepared from the above-ground organs, stems and leaves of Tienchi ginseng. The active ingredient of that is ginsenosides of the saponin. The rhizome is used as crude drug, but the above ground part is treated as food. In order to study the subchronic toxicity of TGT extract, Crl:CD(SD) rats of both genders were administrated TGT extract dissolved by water for injection orally at concentrations of 0 (control group), 100, 300 and 1,000 mg/kg (b.w.) once a day consecutively for 91 days, and observation of general condition, recording of body weight and food consumption were carried out once a week, examination of hematology, blood coagulation and biochemistry, serum protein electrophoresis, measurement of organ weight, and pathology were performed after administration of TGT extract for 91 days after the inspection of urinalysis and ophthalmology at 13 weeks. There is no death case and the change of general conditions according to TGT extract through dosages for 91 days in male and female rats. In addition, the toxic change with TGT extract was not accepted in the inspection item mentioned above. From the above-mentioned result, the subchronic toxicity by TGT extract was considered to be no observable adverse effect level in rat.

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To investigate functionally activity of food components, we used Caenorhabditis elegans (C. elegans) as a model organism and prepared the chemically defined (CD) medium for cultivation. We evaluated the effects of flavonoids such as quercetin, rutin,and catechin which are known as anti-oxidant compounds, and α-tocophrol by their growth stimulation potency. The results indicated that the magnitude of growth stimulation potencies were quercetin > cathechin > rutin >α-tocopherol. This order did not coincident the order of DPPH radical scavenging activity. Moreover, α-tocopherol did not show the growth stimulation at low concentration and affected an adverse effect on C. elegans growth at high concentration. The gene expression analyses by DNA microarray indicated that 141 and 10 genes were changed expression levels significantly by 0.1 mM quercetin and rutin, respectively. All of the rutin responsive genes were included in quercetin responsive ones. Therefore gene expression levels were reflected their C. elegans growth stimulation potencies. dod-6, which were regulated by DAF-16 was up-regulated by both flavonoids. These results suggest flavonoids may act as an antioxidant as well as modulator of DAF signaling processes to exert its growth stimulating properties. Our findings indicate that C. elegans growth cultured by chemical defined synthetic medium is a useful endpoint for function and safety analyses of food ingredients.

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The concentration of uranium (U-238) in various foods containing radioactive cesium (Cs-134 and Cs-137) derived from the Fukushima Daiichi nuclear power plant accident was determined using inductively coupled plasma mass spectroscopy. U-238 concentration in the foods that Cs-134 concentration was below the limits of detection and that was obtained before the accident, were also investigated. U-238 was detected in all 87 samples investigated and the concentration ranged from 0.038 to 130 mBq/ kg. In addition, no correlation was observed between the concentration of radioactive cesium and U-238. The range of U-238 concentration observed in the post-accident food samples was similar to that in the food samples that Cs-134 concentration was below the limits of detection and that in the pre-accident food samples, and to the literature values in foods previously reported. These results suggest that the U-238 concentration was not significantly different in the foods between before and after the accident.

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As a method for nutrition labeling, the quantitative analysis of molybdenum in food by inductively coupled plasma atomic emission spectrometry after dry ashing at 500 °C was studied and validated. Single laboratory validation has been performed to evaluate the trueness, precision, applicability, limit of detection, limit of quantification and linearity of the method, using certified reference material (NIST SRM 1849, infant/adult nutritional formula) and commercial natto (fermented soybeans). The repeatability and intermediate precision of analysis were less than 2.9 and 4.5 % relative standard deviation, respectively, with HorRat_r value 0.24 or less. Recovery tests of molybdenum contents were performed for 13 food samples. Therefore, the recovery rate of molybdenum ranged from 69 to 111 % indicating the high applicability of the method.

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