Poisonous puffer roe has been processed for use as a food by pickling in rice-bran in Ishikawa Prefecture, However, the amount of poison in some of the products was higher than 10MU/g, the value established as the safety limit by the Ministry of Health and Welfare in 1954. Therefore, it was necessary to reduce the amount of poison in the pickled roe. In the course of studies to improve the manufacturing process, the extract-ability of puffer poison by three methods (with 0.1% acetic acid, methanol acidified to pH 4.0 with acetic acid, and water) and the effect of sodium chloride in tetrodotoxin solution on the death time of mice were examined. Moreover, the toxicity of spoiled puffer roe and its extract was tested, as Migita and Hashimoto had reported that toxicity of puffer roe extract was decreased when the roe had become spoiled. The following results were obtained:
1) Among the three methods, water extraction was found to be the most efficient.
2) When tetrodotoxin solution containing sodium chloride was injected intraperitone-ally into mice, their death time was increasingly prolonged as the salt concentration was increased.
3) No clear relation between the toxicity and the spoilage of puffer roe (or its extract) was found in this study.

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The effect of various alkalis on the toxicity of salted puffer roe has been investigated. Firstly, the toxicity of puffer roe immersed in salt solutions containing various alkalis was examined, and sodium bicarbonate was found to be most effective alkali to reduce roe toxicity. Then, laboratory and manufacturing-scale salting processes were done to confirm the efficacy of sodium bicarbonate addition. In the laboratory, the toxicity of salted roe in the presence of sodium bicarbonate decreased remarkably during 9 months, but a less dramatic reduction of toxicity was obtained in the manufacturing-scale experiment.

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Diphenyl, o-phenylphenol, piperonyl butoxide and thiabendazole were given to mice to confirm the potential ability of these compounds to modify the toxicity of other compounds. The acute oral toxicity (LD₅₀) values of equitoxic combinations of these food additives with pesticides as model toxicants were determined with male mice. The expected LD₅₀ of a mixture was calculated from Finney's equation, and compared with the observed LD₅₀. The pesticides studied included BPMC, carbaryl, DDVP, diazinon, EPN, fenitrothion, malathion, nicotine, parathion, parathion-methyl and pyrethrins. All the above food additives increased the toxicity of BPMC, carbaryl, diazinon, EPN and parathion on the one hand, but decreased that of DDVP, fenitrothion, malathion and parathion-methyl on the other.

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A systematic detection and determination method for organic impurities in 7 kinds of food coal-tar dyes (Tartrazine, Sunset Yellow FCF, Amaranth, New Coccine, Fast Green FCF, Brilliant Blue FCF and Indigo Carmine) was developed by the use of high performance liquid chromatography (HPLC) under the following operating conditions: Zipax SAX (strong anion exchange type resin) column; gradient elution system of 0.01M sodium borate solution and 0.1M sodium perchlorate solution; UV detection at 254nm as well as at the maximal absorbance wavelength of each dye. In order to try to introduce HPLC as a purity test in the Japanese Standards of Food Additives (JSFA), a regulation system for organic matter impurities is proposed based on total contents of starting material residues and uncombined intermediates expressed as the amount of sulphanilic acid, while total contents of subsidiary dyes were expressed as the amount of original dyes. By the use of the proposed method, a survey was carried out on 105 samples of coal-tar dyes that had passed the government product examination during 1978-1980.

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The determination of 17 elements (cadmium, zinc, lead, iron, cobalt, magnesium, aluminium, phosphorus, molybdenum, manganese, copper, chromium, nickel, strontium, calcium, barium and vanadium) in brown rice by inductively coupled plasma emission spectrometry (ICP) was investigated. Magnesium had a great influence on the analysis of other elements in the brown rice, but the resultant error could be avoided by correcting the analytical values based on calibration curves of the other elements in the presence of magnesium.
This IPC method resulted in satisfactory reproducibilities for 14 elements (not lead, chromium or vanadium), giving relative standard deviations (RSD) within 0.3-5.0%. The reproducibilities for lead, chromium and vanadium were not so good, showing RSD values of 21.78%, 11.13% and 49.26%, respectively, due to their levels in the brown rice being extremely low. Adequate recoveries of 84-103% were observed for the 17 elements when added to digested brown rice solution.
From these results, the ICP method appears to be excellent for multi-element analysis in brown rice.

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A method for the determination of cyanogenic glucoside in bean paste (nama an) used in Japanese cakes was established by enzymatic assay. The sample was adjusted to pH 5.0 with citrate buffer and incubated with 2 units of the enzyme (linamarase) for 3 hours. The cyanogenic glucoside was thus hydrolyzed to free cyanide, which was estimated, after steam distillation, by the pyridine-pyrazolone method. The enzyme was obtained by ammonium sulfate fractionation of the aqueous extract from butter beans.
The detection limit by this procedure was 0.3ppm linamarin (as hydrogen cyanide) in bean paste. The recovery of linamarin added at 20ppm (as hydrogen cyanide) to the bean paste was more than 92%.
A survey of commercial bean paste by the use of the presented method revealed levels of 0.3 to 97ppm (as hydrogen cyanide) in 46 out of 115 samples. The presented method is believed to be suitable for the quantitative determination of residues of naturally occurring cyanogenic glucoside in bean paste.

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Wet digestion was done in a Soxhlet flask equipped with a digestion cap. Sulfuric acid 1ml, 60% perchloric acid 3ml and nitric acid were added and the mixture was heated. After the digestion, water was added to 25ml. Sulfuric acid 2ml and 50w/v% potassium iodide were then added and cadmium, lead and copper were extracted with MIBK 5ml (potassium iodide-MIBK extraction). When fish oil and brown rice were digested by this method, the time required for digestion was only a quarter to half that of the usual method, and the contamination from reagents and glassware was reduced. Analytical accuracy and precision for cadmium and copper in brown rice were good. The results of potassium iodide-MIBK extraction and DDTC-MIBK extraction of cadmium in brown rice showed a good correlation. This method is rapid and simple, and should be suitable for routine analysis of cadmium in brown rice and of other metals in foods.

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Growth inhibition by the combined use of two or three among three antibacterial substances, hexametaphosphate, glycerol monocaprate and lysozyme, was investigated using four kinds of bacteria, Escherichia coli, Aeromonas hydrophila, Bacillus subtilis and Staphylococcus aureus. These substances showed marked combined effects against E. coli, A. hydrophila and B. subtilis at concentrations below the minimum inhibitory concentration of each substance alone on all three bacteria, though no effect was seen against S. aureus.
E. coli and A. hydrophila were lysed by the combined action of hexametaphosphate and lysozyme, although neither substance alone showed lytic activity. In addition, spheroplasts of E. coli were formed by the action of hexametaphosphate and lysozyme. The above results indicate that the bacteriolysis of these bacteria by hexametaphosphate and lysozyme may be due to the formation of spheroplasts.
Food preservative effect by the combined use of these antibacterial substances was examined in several foods, tofu (soybean curd), yudemen (boiled noodle) and adzuki-an (sweet adzuki-bean paste). Compared with the combined effect in vitro, only a slight preservative effect on the foods was observed.

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A sensitive and simple method for the separation and determination of secondary amines in foods by high performance liquid chromatography (HPLC) with a fluorescence detector is described.
The secondary amines in a food sample were extracted with 0.05N hydrochloric acid. Amines in the extract were readily converted into the corresponding NBD-amines by reaction with 7-chloro-4-nitrobenzo-oxa-1, 3-diazole (NBD-chloride) under alkaline conditions. Eight amines were separated and determined on a Zorbax SIL column with cyclohexane and ethyl acetate (3:2) as the mobile phase.
The limit of determination was 0.2ppm (dimethylamine, DMA). The recoveries of DMA added to cod roe, fish sausage and coocked herring were 100, 81 and 85%, respectively. It was observed that coocked food samples contained larger amounts of secondary amines than raw samples. White and black pepper contained large amounts of piperidine (510 and 250ppm, respectively).

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We have evaluated a new enzymatic method for determining the quantity of lactate contained in liquid milk or milk powder. In the conventional method, hydrazine is required to ensure quantitative enzymatic reaction. However, the new method using glutamic-pyruvic transaminase (GPT) can be conveniently performed at room temperature. The optical density at 340nm is measured using 0.5mol/L glycyl-glycine buffer solution (pH 10.5) at room temperature (25°C) 40 minutes after the start of the reaction. The recovery in liquid milk or milk powder ranged from 87 to 113%.
The results obtained in two different laboratories coincided at the 5% level of significance at lactate levels above 20mg/100g s. n. f., but deviated quite widely below that level. We conclude that this method should be of practical value.

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The tissue distribution and excretion of an insecticide synergist, piperonyl butoxide (PB), after oral and intravenous administration in male rats were investigated by the use of gas chromatography. After the oral administration of PB (250mg/kg), 2.35% of the dose was excreted in feces, whereas none was detected in the 48hr urine. Maximum plasma concentration of PB was attained 5hr after the administration, and the PB concentrations in brain, testis, liver and adipose tissue were higher than the plasma concentration at that time, Some PB remained in the plasma but none remained in the liver, brain and kidney 24hr after the administration; however, the accumulation of PB in the adipose tissue was remarkable and PB was observed even after 96hr.
After the intravenous administration of PB (250mg/kg), PB concentrations in the tissues were higher than those after the oral administration except in the liver, and the amount of PB in the lung was very large, being much higher than that in the adipose tissue.

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A simple and practical method for the determination of nitrite and nitrate in various foods, river water and human saliva is described. It is based on the formation of 4-nitroso-2, 6-xylenol. by the reaction of nitrite and 2, 6-xylenol in a solution of sulfuric acid-water-acetic acid (1:8:1) at 40°C for 30min, and the formation of 4-nitro-2, 6-xylenol by the reaction of nitrate and 2, 6-xylenol in a solution of sulfuric acid-phosphoric acid-water-acetic acid (6:2:1:1) at 40°C for 5 min. The two products are extracted with chloroform and simultaneously analyzed by means of high performane liquid chromatography with an ultraviolet detector (310nm) and a column of Zorbax SIL with chloroform-methanol-acetic acid (98:1:1) as the mobile phase. The detection limits are 0.05μg/ml for nitrite nitrogen and 0.5μg/ml for nitrate nitrogen.
For the determination of nitrite and nitrate in foods, river water and human saliva, addition of silver sulfate and sulfamic acid allows the satisfactory elimination of interfering compounds. The recoveries from several samples were 98.46-100.27% for nitrite and 98.47-101.78% for nitrate, and the relative standard deviations for the whole procedure were 1.47-6.44% for nitrite and 2.07-5.35% for nitrate.

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A method was developed for the determination of propionic acid in bread by high performance liquid chromatography. Propionic acid in bread was extracted with methanol and converted to phenacyl ester by treatment with p-bromophenacyl bromide, with 18-crown-6 (1, 4, 7, 10, 13, 16-hexaoxacyclooctadecane) as a catalyst. The product was injected into a high performance liquid chromatograph equipped with a Nucleosil 5C₁₈ column; the eluent was methanol-tetrahydrofuran-water (20:40:40). Phenacyl ester of propionic acid was determined at 254nm.
Recoveries of propionic acid added to white bread at levels of 2.5 and 5.0mg/5g were 98.7 and 99.2%, respectively. By this method, no propionic acid (less than 10μg/g) was detected in commercial breads.

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[in Japanese]

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[in Japanese]

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