The usefulness of various media for the detection of pressure-injured bacteria was studied. Microorganisms, such as Escherichia coli, Vibrio parahaemolyticus, and Listeria monocytogenes were pressurized to obtain a survival rate of 10-50%, and then spread on several kinds of selective and non-selective media to enumerate viable counts. Detection rates on Trypticase soy agar (TSA), Nutrient agar (NA), Anaerobic bacterial count medium (ABCM) and Bonito-peptone-glucose (BPG) medium were generally superior to those on Brain heart infusion (BHI) and Plate count agar (PCA) medium. In the case of Moraxella sp. counts on BHI were only 1/500 of those on TSA. Addition of horse blood to BHI and PCA increased the detection rates. Detection rates on selective medium were relatively low and variable depending on the selective reagents included in the medium.

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Sunflower roots, stem, leaves and receptacles were extracted with ethanol, and the oily ethanol extracts were partitioned into chloroform-methanol-water (2:2:1.8, by final vol.) by the Bligh-Dyer method to obtain the lipidic fraction in the organic phase. The antimicrobial activity of lipidic fractions were examined by the paper disk method, using E. coil and C. herbarum. The results showed that the lipidic fraction of receptacles contained the strongest antimicrobial activities against these two microorganisms. Four antimicrobial compounds were isolated and purified by silicic acid column chromatography, thin layer chromatography and 15% AgNO₃-thin layer chromatography. The structures of the antimicrobial compounds were determined by spectroscopic analysis, IR, MS, ¹H-NMR and ¹³C-NMR. The molecular weights and molecular formulas of the four compounds (1, 2, 3 and 4) were all 302 and C₂₀H₃₀O₂, respectively, on the basis of the EI-high resolution MS. Examination of the IR and NMR spectra and degree of unsaturation suggested that these compounds were diterpenoic acids. By using ¹H-NMR, ¹³C-NMR, DEPT, ¹H-¹H-NMR and ¹H-¹³C-NMR spectra, the chemical structure of 1 was determined to be trachyroban-19-oic acid. Similarly, the chemical structure of 2 was determined to be kaur-16-en-19-oic acid. The chemical structure of 4 was postulated to be beyer-15-en-19-oic acid on the basis of the NMR spectra.

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The effects of both cultural and pressurizing conditions on the barotolerance of pressurized Escherichia coli were studied by monitoring survivors, injured cells, and release of UV-absorbing substances. An obvious effect of pressurization on E. coli appeared above 1, 500atm, and the survival rate greatly decreased above 1, 800atm. Barotolerance was not affected by medium composition for growth or by the presence of O₂, while it increased with the progress of growth stages. Cells grown at 44°C were less tolerant. The pH value during the pressurization slightly influenced the barotolerance. Survival rate was greatly decreased by pressurization at 44°C. Barotolerance increased with increasing osmotic pressure during the pressurization.

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Paralytic shellfish poison-infested oysters (about 30MU/g) were smoked or boiled and then canned. Dried oyster and oyster sauce were also produced.
The toxicity of canned smoked oyster decreased to under the quarantine limit (4MU/g) or to an undetectable level (<2MU/g). A similar result was obtained in canned boiled oyster. It seems possible to use contaminated oysters safely as canned foods.
In the production of oyster sauce, over 90% of the toxicity was destroyed during condensation (6hrs of boiling in a water bath). As the toxicity of the starting material of oyster broth was under 5MU/g (usually 2-4MU/g), the oyster sauce produced also cleared the official quarantine limit successfully.
On the other hand, the dried oyster product retained a high level of residual toxicity (7MU/g) and was still hazardous.

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A simple and rapid sample preparation method was developed for the determination of carbamate pesticides in agricultural products. The method consisted of methanol extraction, purification by addition of zinc sulfate and sodium tetraborate and reextraction with dichloromethane.
Heat-labile carbamate pesticides were hydrolyzed with NaOH and determined by gas chromatography-mass spectrometry after benzyl derivatization.
The recoveries of 12 kinds of carbamate pesticides fortified at 0.04-0.4ppm in 15 kinds of samples ranged from 63.8 to 134.8% with detection limits of 0.005-0.02ppm, depending on the compounds.
The procedure was applied to 309 products. Methomyl or thiodicarb was detected at 0.02-0.15ppm in four domestic vegetables (cucumber, eggplant, etc.). Carbaryl was detected at 0.01-0.09ppm in seven fruits (orange, apple, etc.).

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Among 9 organic acids commonly used as food additives in Japan, fumaric acid (FA) exhibited the strongest growth-inhibiting (GI) action on 20 Gram-negative bacterial strains tested. Growth of these 20 strains, including 3 Salmonella serovars, Escherichia coli, E. cloacae, Klebsiella oxytoca, K. pneumoniae, Acinetobacter anitratus, Proteus mirabilis, or Pseudomonas aeruginosa, was inhibited within 160 seconds of contact with 0.3w/v% solution of FA, although strains of S. Typhimurium exhibited lower susceptibility than the others. Both Bacillus cereus and Staphylococcus aureus were resistant to the GI action of FA and other organic acids. The GI action of FA was remarkably improved by the addition of 0.3-0.1% ascorbic acid, malic acid, tartaric acid or citric acid monohydrate.

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The thermoluminescence (TL) detection methods for irradiated spices were compared using spice samples obtained on the Japanese market, irradiated at doses of 1, 5, 10 and 30kGy and stored for 1 year before analysis. The TL intensities of irradiated spices were stable for 1 year after irradiation. Measurement with whole samples failed to identify irradiated samples. Minerals were separated from spices in sodium tungstate saturated solution and/or sodium polytungstate solution. The TL intensity of minerals which had undergone irradiation was significantly increased for all samples. However, the ranges of TL intensity of irradiated and unirradiated samples overlapped. Clear discrimination has been obtained between the TL ratios of irradiated and unirradiated spices by using normalized measurement with reirradiation. The detection limit in terms of irradiation dose is 1kGy even in a sample that has been irradiated 1 year prior to analysis. Normalization is the best technique currently available for thermoluminescence analysis to identify irradiated spices.

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A simple, rapid and reliable high performance liquid chromatographic (HPLC) method for the simultaneous determination of eight quinolones (oxolinic acid, nalidixic acid, flumequine, piromidic acid, benofloxacin, danofloxacin, enrofloxacin and ofloxacin) in meat and fish has been developed. The drugs were extracted with 0.2% metaphosphoric acid-acetonitrile (7:3), followed by a Bond Elut C₁₈ clean-up procedure. The HPLC separation was carried out on a Wakosil II 5C₁₈-HG column (150×4.6mm i. d.) with 0.05M phosphate buffer (pH 2.5)-ac-etonitrile (65:35) containing 3.5mM sodium dodecyl sulfate (SDS) as the mobile phase at a flow rate of 0.5ml/min. The drugs were detected by UV detection (at 282nm) and fluorescence detection (wavelength programing). The calibration graphs were rectilinear from 0.1 to 2ng for danofloxacin, and from 1 to 20ng for other drugs. The recoveries of the drugs from meat and fish fortified at the level of 0.2μg/g were 80.8-92.1%, with high precision. The limit of detection was 0.01μg/g for each drug. The method was applied in thermal stability studies of residual oxolinic acid. The thermal stability of oxolinic acid was excellent.

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A method for preparation of sample solutions has been developed for determination of food coal-tar dyes in foods by using pronase. Twelve kinds of dyes were extracted with a mixture of 1% NH₄OH and ethanol from foods which were hydrolyzed by pronase treatment. Then the extract was concentrated under vacuum, cooled in ice, treated with tetrabutylammonium hydroxide and cleaned up by using Sep-pak Plus tC18 cartridges. The dyes retained on the replaced cartridge were eluted with a mixture of methanol and tetrabutylammonium phosphate solution (pH 5.0), and determined by gradient high performance liquid chromatography with visible wavelength detectors.
The recoveries of food coal-tar dyes were more than 76.0% from foods spiked at 1 and 10μg/g levels.

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A new, sensitive and rapid method has been developed for the analysis of fumonisin B₁ and fumonisin B₂ in corn. Fumonisin B₁ and fumonisin B₂ which are the major metabolites produced by the fungi Fusarium moniliforme and Fusarium proliferatum, have been implicated in human esophageal cancer and induced pulmonary edemain pigs and leukoencephalomalacia in horses. Fumonisin B₁ and fumonisin B₂ were extracted from spiked corn with methanol-water (3:1) and then cleaned up by strong anion-exchange (SAX) column chromatography. Fumonisin B₁ and fumonisin B₂ were eluted fromthe SAX column with 1% acetic acid in methanol and quantitated via gradient elution HPLC using precolumn derivatization with 4-(N, N-dimethylaminosulfonyl)-7-fluoro-2, 1, 3-benzoxadiazole (DBD-F) and fluorescence detection. The minimum detectable concentration in corn was 0.01μg/g. Recovery values for fumonisin B₁ and fumonisin B₂ in spiked corn averaged 92 and 90%, respectively, at the level of 0.5μg/g.

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6-Aminonicotinamide is a pellagragenic compound. In this study, the minimum amount of 6-aminonicotinamide affecting the growth of rats fed with a niacin-free, tryptophan-limiting diet was examined. The rats were fed ad libitum with the diet containing 50, 70, 100, 500 or 1000ppm 6-aminonicotinamide for 14 days, and body weight and food intake were measured daily. The lowest dose showing clear growth retardation and decrease in food intake was 500ppm 6-aminonicotinamide. The average intake of 6-aminonicotinamide in this group was 0.45mg/kg body weight/day.

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Trichothecenes and zearalenone (ZEA) in barley samples were surveyed to compare the natural occurrence of the toxins between the southern region and Kangwon province in Korea. Four 8-ketotrichothecenes, namely deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), nivalenol (NIV), and 4-acetylnivalenol (4-ANIV) and ZEA, were detected in barley samples from the southern provinces, and DON, 15-acetyldeoxynivalenol (15-ADON), NIV, 4-ANIV, and ZEA were found in barley samples from Kangwon province. The major toxins in barley samples from both areas were DON and NIV, but there was a regional difference in the natural occurrence of monoacetyl-DON; 3-ADON and 15-ADON were detected in barley from the southern region and Kangwon province, respectively. This is the first report of the natural occurrence of 15-ADON in Korean barley.

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Changes of residue levels of organophosphorus pesticides in corn during storage and processing to starch were investigated. The behavior of bromine during starch processing was also investigated.
Corn grain was treated with DDVP, chlorpyrifos methyl, fenitrothion, pirimiphos methyl and malathion and stored at 10-18°C for 12 weeks, during which time the residue levels of these pesticides declined continuously. The residue levels of pesticides except DDVP were more than 70% and that of DDVP was only 25% after storage of the corn for 12 weeks.
Starch was prepared from corn which contained bromine derived from methyl bromide used for fumigation, and which had been treated with pesticides. The residue levels of DDVP, chlorpyrifos methyl, fenitrothion, pirimiphos methyl, malathion and bromine in the starch were 0.1, 13, 7, 11, 2 and 1%, respectively. Most of the DDVP disappeared during soaking in sulfurous acid solution for 48hrs. Bromine was transferred to the soaking water and washing water.
Pesticides were unevenly distributed in soaked corn. They were accumulated in the germ.

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[in Japanese]

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[in Japanese]

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