Seventy-seven samples of commercial frozen foods were tested to determine E. coli MPN counts. E. coli was detected in 11 samples and the MPN counts ranged from 30 to 930 per 100g.
Of 48 strains isolated from 48 gas-positive EC tubes, 26 strains were E. coli I, 3 strains were E. coli II, and others were K. aerogenes I, C. freundii I and non-coliform organisms.
When these isolates were incubated at 44.5°C in EC tubes, 4 strains of K. aerogenes I did not produce gas. However these 4 strains produced gas in EC tubes containing 1% food material. Moreover, 2 of the 4 strains produced gas in the presence of glucose or sucrose, but the other 2 did not. One of the causes of false-positive results in the EC test of frozen foods may thus be the presence of various carbohydrates in the sample food material.

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The present survey was undertaken to investigate the distribution of enteropathogenic E. coli (EEC) in oyster-farm areas in Hiroshima Bay and to investigate the correlation between food-poisoning outbreaks due to raw oysters and EEC.
A total of 550 samples, including sea water (188), raw oysters (236), river water (72) and bay mud (54), was collected and examined during the winters from Dec. 1969 to Jun. 1979.
The results obtained can be summarized as follows:
1) The isolation rate of EEC was 14.0% (33/236) in raw oysters, 14.4% (27/188) in sea water, 15.3% (11/72) in river water and 3.7% (2/54) in bay mud.
2) The isolates were classified into twenty serotypes. The distribution frequencies were O128:K67 (21/84), O125:K70 (8/84), O127:K67 (7/84), O44:K74 (6/84) and O26:K60, O55:K59, O28:K73, O126:K71 (5/84).
3) Two serotypes of EEC were isolated at the same time from four samples each of oysters and sea water, and three serotypes of EEC from one sample of sea water.
4) In raw oysters and sea water there appeared to be a relationship between the amount of E. coli and the incidence of EEC.
The incidence of EEC-positive samples was slighly higher (p=0.05) in samples with E. coli MPN>230 compared to ≤230 in oysters and higher (p=0.01) in samples with >18 compared to ≤18 in sea water.
These results show that EEC is widely distributed at oyster-farm area in Hiroshima Bay, and suggest that some cases of food poisoning due to raw oysters can be attributed to the eating of raw oysters contaminated with EEC.

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Brown algae contain arsenic higher (22.7-138.3ppm) than other seaweeds and marine foods. The arsenic compound(s) in brown algae can be easily extracted with redistilled water (approximately 40-60% of the initial content).
The chemical form(s) of the arsenic compound(s) in several brown algae, Awabi (Haliotis gigantea) and in human urine after eating Hijiki (Hizikia fusiforme) were studied by gel-filtration chromatography (Sephadex G-15). Arsenic in the fractions were determined by flame-less atomic absorption spectrometry. All of the arsenic compound(s) in the water extract of seaweeds eluted earlier than As₂O₃ (AsO₃^3_-), As₂O₅ (AsO₄^3_-) and phenylarsonic acid. The elution volumes (Ve) of the arsenic compound(s) in Makonbu (Laminaria japonica) and Wakame (Undaria pinnatifida) water extracts were identical (Ve=170ml), but different from that in Hijiki (Ve=200ml). The elution profile of arsenic compounds in Matsumo (Heterochrodaria abietina) water extract had two peaks; the early one had approximately the same Ve as those of Makonbu and Wakame (Ve=165ml), while the latter eluted earlier than Hijiki arsenic (Ve=190ml). The elution volume of the arsenic compound(s) in Awabi water extract and in the urine after Hijiki intake, however, was the same as that of Hijiki.
On the other hand, an organo arsenic compound in cod liver hydrolysate was isolated by Lunde. According to his report, the UV spectrum of the organo arsenic compound showed a distinct peak at 260nm and the compound contained at least one amino group which is positive in the ninhydrin reaction. However, we found no absorption at 260nm corresponding to any arsenic elution peak from seaweed. The fractions of Hijiki water extract were examined using the ninhydrin reaction, and slight coloration was seen at the position of arsenic.

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An analytical method was developed for determining residue of phosphoric acid triesters (tri-n-butyl phosphate, tris (2-chloroethyl) phosphate, tri-n-amyl phosphate, tris (2, 3-dichloropropyl) phosphate, triphenyl phosphate, tris (2-butoxyethyl) phosphate, tricresyl phosphate, tris (2, 3-dibromopropyl) phosphate, tris (4-tert-butylphenyl) phosphate in fish, sea sediment and sea water. Phosphoric acid triesters were extracted from these materials with acetonitrile and methylene chloride. After n-hexane-acetonitrile partition, the extract was cleaned up by activated charcoal column chromatography, followed by extraction with conc. sulfuric acid, washing with 0.5N sodium hydroxide solution, and finally Florisil minicolumn chromatography. The purified extracts were analyzed with a gas chromatograph equipped with a flame photometric detector (P-filter) and with a gas chromatograph-mass spectrometer. The separation on gas chromatography was found to be good with 10% OV-1 on Chromosorb W experiments (AW-DMCS) and 5% FFAP on Gas Chrom Q. Throughout the present method, the recoveries of phosphoric acid triesters were in the range of 60-95%, and the detection limits (fish) were approximately 1-5μg/kg.

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Dimethylamine (DMA) levels in the extracts of 25 rubber articles were studied by gas chromatography. DMA was detected in H₂O or 1N HCl extracts of 15 samples obtained under reflux for 1 hour, in amounts of 3-1280 and 17-2830mg/kg, respectively.
Vulcanizing accelerators containing dimethylamino groups in their structures were detected in benzene extracts of these rubber articles by thin layer chromatography.
Thiuram-type vulcanizing accelerators were almost completely decomposed to DMA on reflux with H₂O or 1N HCl for 1 hour, but dithiocarbamate degradation varied very greatly depending on the kind of solvent and the salts present.
It can be concluded that DMA in rubber extracts is the decomposition product of vulcanizing accelerators containing dimethylamino group in their structures, and that DMA can be extracted fairly effectively from unaltered vulcanizing accelerators in rubber articles using H₂O or 1N HCl.

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Artificial nipples are made from isoprene rubber, natural rubber or silicone rubber. Those made from isoprene rubber were found to contain dibutylhydroxytoluene (BHT), but the others were not.
The amount of BHT transferred from an isoprene rubber nipple to milk was trace-0.34ppm, In repeated tests, the amount tended to decrease, and the maximum daily intake was determined to be 1/31.6-1/12.5 of ADI. This amount of BHT is not considered to affect the health of babies, but from a general food hygienic point of view, it is desired to reduce the daily intake as far as possible.
Accordingly, initial removal of BHT from nipples resulted in a marked decrease in the amount of BHT migrating into milk to a very low level that seemed reasonable.

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Freshly harvested wheat and barley of the 1977 crop were examined for trichothecene mycotoxins contamination and for the presence of Fusarium species.
Trichothecenes such as deoxynivalenol, fusarenon-X, nivalenol, diacetoxyscirpenol, neosolaniol and T-2 toxin were not detected in these samples. The incidence of Fusarium contamination ranged from 0 to 32.7%.
The most common species was F. graminearum; 73.7% of the total Fusarium isolates (810 strains) belonged to this species, followed by F. equiseti, F. oxysporum, F. semitectum and F. avenaceum (8.0%, 5.6%, 3.3% and 3.3%, respectively). Frequencies of F. tricinctum, F. poae, F. moniliforme, F. acuminatum, F. merismoides, F. solani and F. sulphureum were very low in these samples.
The occurrence of trichothecene-producing strains in the 179 isolates selected was 43%. Among 57 isolates of F. graminearum, 43 produced both nivalenol and fusarenon-X, and 4 produced deoxynivalenol. Several trichothecenes, such as nivalenol, fusarenon-X, diacetoxyscirpenol and neosolaniol, were produced simultaneously by 16/25 isolates of F. equiseti and 8/23 isolates of F. semitectum. Three of 4 F. acuminatum produced both T-2 toxin and neosolaniol, and one of 5 F. poae also produced neosolaniol.

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From May 1976 to October 1978, 17 incidents of food poisoning involving 125 persons occurred in the Kyushu district. An epidemiological survey, showed that all the patients had eaten raw flesh (arai) and soup (koikoku) of the carp (Cypriniformes cyprinus). They exhibited symptoms of the nervous system, for example vomiting, convulsion, numbness, speech impediment and difficulty in rising and walking.
All the carp involved appeared fresh and normal, and there was no evidence of microbial contamination.
When the carp flesh that had caused the food poisoning, or hot-ethanol extracts of it, were administered to two dogs, they showed the same symptoms as humans. These symptoms were also observed in monkeys and cats on either oral or intraperitoneal administration. However, mice were less sensitive to the poison.
These findings indicated that the carp flesh contained a hot-ethanol-soluble toxic substance. When the crude extracts were subjected to thin layer chromatography after clean-up, the toxic substance could be detected as a distinct blue-green spot on the plate by spraying 20% sulfuric acid, then charring. Using both the blue-green spot and the toxicity as markers, the crude substance was purified by simple liquid-liquid partition, column chromatography and preparative thin layer chromatography.
The purified substance showed one spot on a thin layer chromatographic plate. Physical data were: m/e 575 (parent mass peak) and UV λ^EtOH_max, 220nm and 282nm. Studies are in progress to determine further properties and to identify this substance.

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Generally, heavy metals in food have been discussed in terms of inorganic salts in the field of hygienic chemistry, partly because of analytical methods used. However, in order to evaluate accuratly their biological characteristics, such as absorption, excretion, accumulation and toxicity, the chemical forms present in natural food should be identified. In Japan, marine algae are eaten as food. Since they contain relatively high levels of arsenic compared with other heavy metals, the chemical form of arsenic was investigated. Hijiki (Hijikia fusiformis) contains a large amount of arsenic compounds, corresponding to about 100-180ppm as A_S2O₃ in dry samples. Twenty-five percent of the arsenic in Hijiki was readily soluble in water; the remainder was fat-soluble or conjugated with tissue components. The water-soluble arsenic was also soluble in methanol and ethanol, and may consist of low molecular weight organic compounds, based on the results of gel permeation chromatography and ultrafiltration. Seventy-five percent of this material was adsorbed on weak cationic exchange resin (Dowex CCR-2); it could be eluted with 0.01N hydrochloric acid and yielded white tetrahedral crystals, having weak UV absorption at 279nm. High performance liquid chromatographic analysis of this material showed that the pattern of absorbance at 279nm in the elute essentially coincided with that of arsenic concentration. This material, which is a major component of the arsenic-containing compounds in Hijiki, thus appears to be an organo-arsenic compound.

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An analytical method was investigated for the simultaneous detection and determination of tert-butylhydroquinone (TBHQ), BHA and BHT in edible oil by thin layer and gas chromatography.
The method was as follows. The sample was dissolved in n-pentane and extracted with acetonitrile. The acetonitrile extract was separated into TBHQ, BHA and BHT by thin layer chromatography using silica gel. The spots were detected on TLC by spraying with 2, 6-dichloroquinone-4-chloroimide, phosphomolybdic acid and dimethylamine as chromogenic reagents. Dimethylamine showed a coloring reaction only for TBHQ. In the cace of gas chromatography, simultaneous determination of TBHQ, BRA and BHT was possible using an OV-17 or SE-30 column.
The recoveries of TBHQ, BHA and BHT added to various edible oils were in the ranges of 89-97%, 93-99% and 87-95%, respectively.
The present method was found to be satisfactory for the simultaneous determination of TBHQ, BHA and BHT in edible oil.

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