Xanthene dyes such as erythrosine, eosine, phloxine, rose bengale when exposed to visible light have lethal effects on bacteria at concentrations at which the bacteria can still duplicate in the absence of light.
Y. Kurayuki et al. have reported on the formation of resorcinol, phthalic acid and other decomposed products in the fading solution of xanthene dye exposed to daylight. But in our experiments the lethal activities of those decomposed products on bacteria were negligible. And as the photodynamic activities in xanthene dyes as well as methylene blue and proflavine can be found only in aerobic condition, the photodynamic effects on bacteria presumably are due to the oxidation of some component of bacterial cell. This mechanism is simillar to that of photochemical oxidation reported by G. Oster et al.

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The quantitative thin layer chromatographic method of a greenish fluorescent substance, 2, 3, 4-trichloro-5, 7-dibromo-6-hydroxyxanthone-1-carboxylic acid found in commercial phloxine (Food Red No. 104) was studied.
The maximum wave length of this substance was at 251mμ and 368mμ in 0.1N sodium hydroxide solution. The calibration curves were linear in the range of 1-10μg/ml at 251mμ and 1-20μg/ml at 368mμ (Fig. 1). The maximum of the spectrum shifted from 368mμ to 383mμ by addition of ethyl alcohol. Also the determination of this substance was readily performed with a fluorometric method. The calibration curves were linear in the range of 1×10^-7M-4×10^-6M at 494mμ (emission maximum) (Fig. 3). The fluorescence intensity was increased by addition of ethyl alcohol, and the maximum of intensity was obtained the ratio 1: 1 between 0.2N sodium hydroxide solution and ethyl alcohol (Fig. 2).
The quantitative thin layer chromatographic method was applied for the determination of 2, 3, 4-trichloro-5, 7-dibromo-6-hydroxyxanthone-1-carboxylic acid in commercial phloxine. The amount of this substance was measured with an ultraviolet spectrophotometric and fluorometric methods after it is separated on chromatoplates using a solvent system of methyl ethyl ketone, n-propyl alcohol and distilled water (20: 2: 3) and eluted with distilled water. The recovery in these methods was satisfactory to both an ultraviolet spectro-photometric and fluorometric methods, and the results obtained are shown in Table 3. In case of the ultraviolet spectrophotometric method the absorbance at 251mμ and 368mμ of the material eluted from the silica gel layer has influence on the determination of this substance. Therefore, the absorbance at these wave lengths was investigated using various silica gel adsorbent (Tables 1 and 2). On the silica gel layer the minimum detectable amount was found to be 0.01μg of 2, 3, 4-trichloro-5, 7-dibromo-6-hydroxyxanthone-1-carboxylic acid (Table 4). Commercial phloxine was found to contain 1-3.02 per cent of this substance (Table 5).

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The fluorometric method for determination of formaldehyde by means of Hantzsh reaction reported by Sidney Belman was improved and a new determination method of formaldehyde in food was established.
To 5ml of formaldehyde solution in a test tube is added 1ml of acetylacetone reagent and the test tube is heated in a boiling water bath for 10 minutes. After cooling to room temperature, 4ml of ethyl-alcohol is added. The solution gives a fluorescence spectrum with an excitation maximum at 416mμ and an emission maximum 500mμ.
A linear line relationship between formaldehyde concentration and fluorescence intensity was obtained within the range of 0.05-0.5μg/ml.
Influence of other substances on the reaction was studied in detail. This method was successfully applied to the determination and the identification of formaldehyde in several foods.

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The low molecular hydrolyzates obtained under hydrolysis of sodium carboxymethyl-starch (Na-CMS) with human saliva amylase was hydrolyzed again with some carboxylases or hydrochloric acid. The substances were almost unhydrolyzed with carboxylases, however, was hydrolyzed with hydrochloric acid.
Paper chromatogram of the hydrolyzates showed apparant four spots, and these were the same Rf values as glucose, maltose, maltotriose and maltotetraose. On each of these hydrolyzates purified with DEAE ion exchange cellulose the carboxymethyl group was recognized by the absorption spectra of the color produced with 2, 7-dihydroxynaphthalene in sulfuric acid and infrared spectra, and the degree of substitution were between 0.71 and 1.03.

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The powder of the commercial pre-cooked Chinese noodles was preserved in an incubator at 50°C to make fats rancid, and then, the fats were extracted every week from the powder by the method of Folch, et al. Using those fats the authors investigated the relationship between the degree of rancidity of the fats and the acute toxicity to mice.
It was shown generally that the five indices which indicate the degree of rancidity of fats changed remarkably in the samples during preservation for 6 to 8 weeks. Iodine value decreased remarkably after 6 weeks, on the other hand, acid value increased markedly at the same time. Peroxide value (POV) had its maximum after 6 weeks, and decreased markedly after 8 weeks and later. Carbonyl value raised sharply after 6 weeks, and remained almost unchanged later. TBA value raised sharply after 6 or 7 weeks, when it had its maximum, and fell down later.
From the data of thin-layer chromatography and infrared spectra of the rancid samples, it was shown that as the rancidity progressed triglyceride in those samples decreased, diglyceride increased conversely, and monoglyceride and free fatty acids came to be detected after 5 weeks.
Although it had been described by another authors that the toxicity of the rancid fats was parallel to those POV, from the result of our toxicity test to mice (30ml/kg, a single oral administration) it was found that the toxicity was very low in the sample having high POV preserved for 7 weeks (mortality, 20%), was very high in the two samples having lower POV preserved for 8 weeks and having more lower POV preserved for 14 weeks (mortality, both 100%).
Therefore. it is considered that the toxicity of the rancid fats is not always caused by fatty peroxide, but is much ascribed to more oxidized products.

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In this paper the authors investigated the composition of fatty acids in fats extracted from the pre-cooked Chinese noodles preserved as the same way in the previous report, and the fractionation of the fats by column-chromatography on Florisil, and then, the toxicity test on the fractionated fats to mice.
After the separation of the extracted fats into the two fractions of the esterified and the free fatty acids, the composition ratio of fatty acids in each fraction was calculated by gas-chromatography with FID, respectively.
In the fraction of the esterified fatty acids the ratio of the unsaturated fatty acids decreased remarkably in the sample preserved for 7 weeks, on the other hand, in the fraction of the free fatty acids, it did so in the sample preserved for 6 weeks. In the both fractions linoleic acid decreased most greatly, and oleic acid secondly.
An unknown peak was found just in front of the peak of stearic acid on gas-chro-matogram of the free fatty acid fraction in the sample preserved for 5 weeks and more longer, and its retention time was identical with that of 8-formyloctanoic acid which was the product derived from methyl linoleate by auto-oxidation.
From the result of the toxicity test by oral administration to mice on the samples obtained by fractionation of the fats incubated for 14 weeks which were most toxic to mice (mortality, 100%) in the previous report, it was found that the mixed fraction of monoglyceride and free fatty acids was most toxic (mortality, 70%).

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Since a number of heat-resistant Clostridium perfringens have often been harbored in the intestine of a normal healthy people: 1) It is necessary to confirm complete agreements in the sero-type of the isolates of incriminated foods and of patient feces, when we make a retrospective laboratory diagnosis on food poisoning cases in which Cl. perfringens have been suspected as a causal agent. 2) If we failed to obtain the incriminated food, it becomes more difficult to determine the causal agent. viz., it is required to prove that more than 90% of the patients is discharging the same sero-type of organism within their 3rd day of the illness, and more than 70% on their 7th day respectively.
During 1963-69, there were 9 cases of outbreak of food poisoning due to heat-resistant Cl. perfringens in Tokyo. These are summerized as follows;
Case 1: On 20-21st of September 1963, a large scale food poisoning occurred, affecting a total of 1, 491 out of 1, 968 employees (affection rate 75.8%) of the 38 companies, who took a lunch delivered by the same caterer. The patients complained of diarrhea and abdominal pain within 8-15 hours after the ingestion of the lunch. Boiled whale meat contained in the lunch was supposed to be the incriminated food, which had been allowed to stand at room temperature overnight after cooking. Hobbs' type 4 organism was isolated from the meat. On the other hand, on the 3rd day of the illness, Hobbs' type 1 and 4 were isolated from 293 of 379 feces of the patients. From the fact, as shown in Table 2, the outbreak was presumed to be combined infection with both of Hobbs' type 1 and 4 organisms.
Case 2: On 17-18th of July 1964, 183 out of 242 persons (75.6%) who had eaten pickled horse-mackerel for their lunch at the employees' canteen, complained of diarrhea and abdominal pain. Ninety-nine of 183 feces (71.0%) of the patients, collected on the 7th day of the illness, were positive Hobbs' type 5 organisms. It was then diagnosed as a food poisoning case due to the heat-resistant Cl. perfringens Hobbs' type 5, although the incriminated food was not available.
Case 3: On 3-4th of September 1964, 165 out of 232 persons (71.1%) who took “Inarisushi” one of the Japanese meal for their lunch at the employees' canteen, complained of diarrhea and abdominal pain. Average incubation period was 12.5 hours, and heat-resistant organism Hobbs' type 13 was isolated from 35 of 39 patients (89.7%) on the 3rd day of the illness. Then, it was suspected to be a food poisoning case due to the heat-resistant Cl. perfringens Hobbs' type 13.
Case 4: On 28-30th of April 1966, a total of 657 out of 892 persons (73.7%) of 49 companies, who took Scotch egg for their lunch, which was delivered by the same caterer, complained of diarrhea (86.1%) and abdominal pain (66.1) within 5-30 hours after the ingestion of the lunch. Twenty-two point two per cent of the patient complained of their dullness, but few nausea and vomiting. Hobbs' type 2 (2.8×106) and 4 organism (2.4×106) were detected from 1 gram of scotch egg. Detection rate of the organisms from the patients were 92.7% on the 1-3rd day of the illness. Among the 1, 765 strains of the isolates, 375 strains (21.2%) were typed into Hobbs' type 2, and 1, 133 strains (64.2%) into Hobbs' type 4 respectively. Accordingly, the outbreak would be due to combined infection with Hobbs' type 2 and 4 organisms.
Case 5: On 29th of April 1967, a food poisoning occurred at a certain inn in Kanagawa prefecture, affecting 152 out of 244 persons (62.3%) who had happen to stay at that inn, manifested a typical symptoms of the food poisoning, although failed to point out the incriminated food. Hobbs' type 1 organism was isolated from the feces of all 8 patients on the 4th day of the illness and presumably the cause of the outbreak.

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The identification of 19 protein composing amino acids by paper electrophoretic method was investigated.
By using 5N acetic acid as the electrolyte, 19 amino acids were grouped into four groups, that is A (Lys, Arg, His, Gly, Ala), B (Val, Leu, Ileu, Ser, Thr), C (Ser, Thr, Met, Glu, Pro, Phe), D (Tyr, Cys, Asp, Try, Hypro), and the individual amino acid in these groups was identified by the further electrophoresis with 3% aqueous ammonia as the electrolyte.
Amino acids of E group (Thr, Met, Phe) and F group (Tyr, Hypro), could not be separated in this case, were tried with 1% borax as the electrolyte.
By the above mentioned method, the amino acids, in this study, could be separated and identified mutually, except the discrimination between Leu and Ileu, Met and Phe.

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