Japanese people are concerned about internal exposure to radiation through the consumption of contaminated food and water and external exposure due to environmental contamination. Using the coefficient of 0.05 Sv^-1 for the overall risk of dying from cancer and radiation doses derived from Cs-134, Cs-137 and I-131, the degree of exposure and risks were evaluated for different levels of radioactive contamination. Our results showed that the risk of internal exposure is less significant compared with that of external exposure in areas with relatively high dose rates, or so-called radioactive hot spots. Appropriate monitoring of radioactive contamination of food and disclosing the results are prerequisite for ensuring food safety and human health.

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We investigated the effects of an oral administration of daily millet grain feed in type 2 diabetic mice. Mice (C57BL/KsJ-lepr^db/lepr^db, db/db) were fed a diet containing 20% proso millet (PM) , Japanese barnyard millet (BM) , or adlay (AD) powder based on AIN-93G for 21 days. As a result, the HbA1c concentration of whole blood was lower in the diabetic PM- and BM-fed groups than in the diabetic control (AIN-93G) group. Concentrations of hepatic lipid parameters, such as lipids, total cholesterol, and triglycerides in the BM- and AD-fed groups were lower than those in the diabetic control group. In addition, the concentration of bile acid in feces was higher in the diabetic BM- and AD-fed groups than in the diabetic control group. Although gene expression of cholesterol synthesis enzymes such as 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR) was not different between the diabetic mice groups, that of bile acid synthesis enzymes such as cholesterol 7 α-hydroxylase (CYP7A1) was higher in the diabetic BM- and AD-fed groups than in the diabetic control group. These results suggest that PM and BM grains have hypoglycemic activity, and BM and AD grains have hypolipidemic activity. The effect of improved lipid metabolism by BM and AD grains is attributed to the acceleration of bile acid synthesis in liver along with its excretion into feces.

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Conventional plate counting for Escherichia coli is time consuming, and more rapid and specific quantification methods are desired. The fluorescence in situ hybridization with filter cultivation (FISHFC) method has already been developed to specifically detect viable microorganisms such as Listeria monocytogenes, Clostridium perfringens and Staphylococcus aureus. The purpose of this study was to develop and estimate the accuracy of the FISHFC method for E. coli detection in food samples. An Alexa Fluor® 647-labeled oligonucleotide probe, ECO636, targeting a species-specific sequence of E.coli 16SrRNA was designed. ECO636-conferred fluorescence was observed for E. coli and Shigella spp. micro-colonies, but not for any other organisms. This suggests that the ECO636 probe is highly specific for E. coli and Shigella spp. This assay using the FISHFC method can be completed within 9 hours, including a 7-hour cultivation period, and is much faster compared to standard plating methods, which require more than 4 days, for the confirmation of E. coli. Viable E. coli counts in food samples determined by the FISHFC method were not significantly different to those obtained by the conventional plate counting method (p>0.05). These results suggest that the proposed FISHFC method is more rapid than and equally as reliable as the standard methods used for estimating viable E. coli numbers as indicators of food contamination in food.

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We examined the bacteriostatic effect of organic acids on spores in vegetable beverages. A fixed quantity of organic acid (citric acid, malic acid, acetic acid or lactic acid) was added to SCD medium, vegetable juice, and commercial vegetable beverages, and the pH of the solutions was adjusted. The solutions were then inoculated with a spore suspension (1.0×10⁴ cfu/ml) and cultured at 35°C for 4 weeks. We tested for bacteriostatic effects based on whether or not there were any increases in bacteria. A bacteriostatic effect was observed at pH 4.6 with 80 mM citric acid, 40 mM acetic acid or 10 mM lactic acid, at pH 4.4 with 40 mM citric acid, 20 mM acetic acid, or 5 mM lactic acid, and at pH 4.2 in the presence of 5 mM organic acid. Organic acid had a bacteriostatic effect on both vegetative cells and spores, with effectiveness changing depending on the concentration and pH.

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We previously reported that a polyphenol-rich fraction, CSD3, of the fruit of Chaenomeles sinensis neutralizes seasonal influenza viruses. In this study, we examined whether CSD3 possesses antiviral activities against the H1N1 virus of swine origin that caused a global pandemic in 2009. Treatment of the pandemic influenza virus, A/Chiba/1001/2009 (H1N1) pdm, with CSD3 at 250 μg/ml decreased viral infectivity by 1/3 000. This indicates that the anti-viral components in C. sinensis are also effective against the 2009 pandemic influenza virus. In addition, infectivity was suppressed five times more than hemagglutinating activity with CSD3 treatment at 5 μg/ml, suggesting that CSD3 inhibits at multiple steps of infection, particularly the steps after adsorption.

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The main sources of vitamin C (VC) for humans are vegetables and fruits. However, ascorbic acid (AsA) in food is easily destroyed during the cooking process and storage. Therefore, VC obtained at mealtime is mainly associated with the VC content of fresh vegetables, and to the cooking method or storage period of the food. In the present study, VC content of 15 fresh vegetables, 15 cooked vegetables cooked by two methods, and 8 vegetables purchased from a delicatessen were determined by HPLC. The results from the 15 cooked vegetables demonstrated that the residual percentage of VC soon after cooking was higher in fried vegetables than in boiled vegetables. However the residual percentage of AsA in cooked vegetables after 24 hours of cold storage was higher in boiled vegetables than in fried vegetables; in the latter case, the residual percentage of AsA was 26.3% as compared to uncooked vegetables. The comparison of 8 cooked vegetables with those purchased from a delicatessen revealed that the residual VC and AsA content in delicatessen vegetables was about 1/2 and 1/4, respectively, of that of cooked vegetables soon after cooking.

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[in Japanese]

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As heating proceeds during the cooking of rice, starch granules within the rice grains absorb water, swell, and then gelatinize. To determine the optimal cooking conditions for various kinds of rice, it is desirable to be able to detect differences in the water absorption of rice grains during cooking. NMR imaging was used to follow changes in the content and distribution of water during the cooking of Nipponbare (Japonica), Khao Dawk Mali (Indica) and High Amylose (Indica) rice. Samples were cooked for various cooking times in closed-glass vials, quenched to stop the cooking process, and then investigated using two-dimensional multi-echo 1H imaging at room temperature. Images obtained from the first-echo revealed changes in the water distribution of the rice grains. T₂ images calculated using the echoes were converted into quantitatively reliable contour maps of the water concentrations using an empirical T₂ vs. water content calibration determined from a series of water/rice starch mixtures. Japonica rice samples with different milled ratios were also investigated to observe the effect of rice grain husks on water absorption. The degree of gelatinization of rice during cooking was measured by the β-amylase·pullulanase method (BAP) and Fourier-transform infrared spectroscopy (FT-IR/ATR). An FT-IR peak seen at around 1 000 cm^-1 increased with increasing cooking time. There was a high correlation in the degree of gelatinization between the FT-IR method and the BAP method.

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Simple theoretical equations were proposed for water ¹H T₂ (T_2obs,W) observed in wide-line NMR experiments with three cases of food gels in which polysaccharides or protein polymers have the conformations of random coils or ordered structures (case A), both random coils and ordered structures (case B), or random coils, ordered structures and aggregated structures (case C). On the basis of the equations, the temperature dependencies of T_2obs,W were calculated for solutions with polymers in random coils and ordered structures. The steep change of T_2obs,W around the conformational transition temperature, which is frequently seen for food gels, was reproduced by changing the ratio of polymers with the random coils and ordered structures. The formation of aggregated structures was also described. Experimental results of T_2obs,W for a gelatin solution and carrageenan solutions were demonstrated and compared with the theoretical values given by the equations. The temperature dependencies of the T_2obs,W values were well related with the conformational changes of the polymers in those solutions.

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