The influence of serotonin on provoking diarrhea in enteritis caused by Vibrio parahaemolyticus was investigated. The rhesus monkeys were fed with 50ml of vibrio cultures in Brain Heart Infusion media and one hour later, 100 microgram of serotonin was injected intravenously. In the case of pathogenic strain, i. e., strain 4167, in four of five test animals severe watery diarrhia were observed 2-6 hour after feeding. No variation occurred in the concentration of serotonin in blood and small intestine, while in the case of feeding with the same strain without administration of serotonin, they level down to about one-half of normal level 4 hour after the feeding. From these results, it is supposed that the level of serotonin in tissues of digestive tracts might play an important role in manifestation of food poisoning symptoms due to the pathogenic vibrio strain.

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The authors carried out epidemiological and bacteriological investigations on two outbreaks of food poisoning due to heat-resistant C. perfringens (not related to Hobbs types 1-17) occured in Shizuoka prefecture, in October 1968 and October 1969.
Results obtained were as follows:
(1) In both outbreaks the symptoms, appearing 7-19hr. after the patients had eaten the meal, were abdominal pain and diarrhoea with little vomiting. Pyrexia and headache were not recognized. The illness disappeared in a day or two.
(2) In outbreak 1, in a company in Shimizu city, the food suspected was a meat-dumpling (mixed minced chicken, egg yolk, starch and salt) cooked with soy sauce and sugar on the previous evening. A count of 3 million C. perfringen per gram was obtained from its remains. Heat-resistant strains were found in ten of the eleven samples of faeces from patients. The greater part of the strains isolated from food and faeces were not agglutinated by Hobbs types 1-17 antisera, and an antiserum was prepared against the strain (F7-2a) isolated from the meat-dumpling. This antiserum agglutinated 31/62 strains isolated from eight samples of faeces and two samples of food.
(3) In outbreak 2, in an office in Fujieda city, no food was available for examination. Faeces were collected from fifteen patients and heat-resistant C. perfringens were isolated from all samples. None of the strains isolated was agglutinated by Hobbs types 1-17 antisera, but 45/50 strains from fourteen samples of faeces were agglutinated by the antiserum prepared against the strain (F7-2a) isolated from the food in outbreak 1.

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Browning of fish jelly products, “Kamaboko”, “Chikuwa”, and “Agekamaboko”, was studied from microbiological points of view. Four strains of about 100 bacteria isolated from browned fish jelly products changed “Kamaboko” to brown to black. These bacteria were identified as a new species, Achromobacter brunificans. By an inoculation of Ach. brunificans on “Kamaboko”, brown dots appeared on the surface and extended to the interior part. Its peculiar elasticity and pH reduced with browning. Bacterial tyrosinase may not play a role for browning because Ach. brunificans does not show its activity. However, it seems likely that glucose is important for this phenomenon since browning has been found only on the fish jelly products containing glucose.

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Effects of carbohydrates, proteins and amino acids on browning of fish jelly products, “Kamaboko”, “Chikuwa”and“Agekamaboko”, due to Achromobacter brunificans were studied. Glucose among carbohydrates tested was most effective. Brown substance was abundantly formed on a system of glucose and various proteins except zein, of glucose and L-glutamic acid or L-histidine, and of L-glutamic acid or L-histidine and several carbohydrates such as D-xylose, L-arabinose, and saccharose. With an increase of substrate concentration, the browning was recognized more distinctively. Brown substances formed by Ach. brunificans and by heating were paper-chromatographically similar. It seems likely that the browning is due to amino-carbonyl reaction between carbohydrates and amino compounds.

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It has been assumed that diphenyl chloride (DC) wasthe toxic substance of“the Food Poisoning of Rice Oil”which happened at and near the northern part of Kyusyu from summer to autumn in 1968 in Japan.
The authors investigated the method of isolation and determination of DC from the animal tissues and organs by X-ray fluorescence analysis and further the content of DC in excreta and the distribution of DC in tissues and organs after oral administration of DC to rats.
During 48 hours after a single oral administration of 2ml of the rice oil containing 2, 500ppm of DC to rats, about 10% of dosed, DC was excreted in to feces but was not in urine at all.
In the case of the continuous administration of DC, after the oral administration of 2ml of the rice oil containing 2, 500ppm of DC to rats everyday during a week, DC was found most abundantly in skin, less abundantly in muscles, intestines, liver, pancreas, and lungs, but hardly in heart, genitals, spleen, blood or brain.

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Bacteriological studies have been conducted on the flat souring deterioration of fish sausage.
The spoiled sample showed pH down and a large amount of acetic acid and formic acid were detected in them. At the same time, viable bacteria was found at the level of about 104 per gram. The isolated strain was identified to be Bacillus coagulans which is known as the causative bacteria of flat souring of canned milk products and tomato products.

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As results of survey of toxigenic molds growing on rice stored for private consumption by farmers, a seasonal vicissitude of mycoflora from “field type” to “storage type” was observed. As “storage type” fungi, Aspergillus ochraceus, A. versicolor, A. glaucus and some Penicillium, Candida, Fusarium and Cladosporium fungi were found to be predominant. Two strains out of 59 A. ochraceus were confirmed to produce ochratoxin A, and 18 strains out of 58 A. versicolor examined were found to producesterigmatocystin. From the toxic A. clavatus, patulin was detected by TLC but no aflatoxin producing strains were found from the fungi belonging to A. flavus and A. oryzae groups. Although the toxicity assay on Penicillium fungi is now being continued, the fact that the so called “yellow rice molds” such as P. islandicum, P. citrinum have been detected, should be strongly interested.

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The investigation on the toxigenic fungi contaminating home-made miso and soy sauce was carried out. A strongly toxic strain of Aspergillus ochraceus and to toxic strains of Penicillium, cyclopium were found as a result of the investigation in which 46 samples of miso and 11 samples of soy sauce collected in Tohoku district were examined. The production of ochratoxin A in Aspergillus ochraceus was recognized by thin layer chromatography and the toxicity bioassay with chicken embryo and mouse.

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Recovery tests were carried out on 18 bacterial strains, in order to reveal the effct of different plating techniques and the influence of addition of milk on the C. V. T. counts, using 2 kinds of commercially prepared C. V. T. medium (CI medium; containing 1ppm of crystal violet: CII medium; containing 2ppm of crystal violet).
Recoveries of test strains from the pour plates were almost equal to the smeared plates of CI or CII medium.
Gram negative strains increased in recoveries by the addition of milk (1.0ml of skim milk to the pour plate; 0.1ml of skim milk to the smearing plate surface) to the CII plates, and bacillus strains were allowed to grow in the pour plates of milk added CI medium. These results suggested that addition of milk to plates, in case of milk sample of low bacterial counts, resulted in losing or decreasing the selectivity of C. V. T. medium.
And the counts of CI medium were markedly greater than those of CII medium, where the 7 strains of Gram negative bacteria were recovered below 50% in compared with the counts of Standard Method Agar as the control medium.

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[in Japanese]

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