PCB, polychlorinated quaterphenyl (PCQ) and polychlorodibenzofuran (PCDF) were detected in Kanemi rice oil that caused the “Yusho. ” These chemicals could be attributable to the thermotransfer medium, which leaked out into Kanemi rice oil in the deodorizer, but the ratios of PCQ/PCB and PCDF/PCB in the oil were found to be extraordinarily high in comparison with those in the original thermotransfer media. In this paper, the rice oil which was spiked with only PCB or PCB, PCQ and PCDF was deodorized using a laboratory deodorizer, and the changes of concentration of the chemicals were investigated. 1) PCQ and PCDF formation from PCB by deodorizing The rice oil which was spiked with 10, 000ppm of purified Kanechlor 400, a Japanese commercial PCB preparation containing 48% chlorine, was deodorized in a laboratory deodorizer. The oil was saponified, extracted, washed and concentrated. The concentrated extract was then cleaned up by Florisil and alumina column chromatography to obtain the PCQ and PCDF fractions which were further perchlorinated in order to confirm the chemicalsi. PCQ was not formed from PCB by deodorizing, but it was recognized that PCDF was formed h a small quantity, i. e., the PCDF level in the oil was 3ppb. 2) The concentration change of each component, PCB, PCQ and PCDF by deodorizing The rice oil which was spiked with 2, 375ppm of purified Kanechlor 400, 90ppm of PCQ and 1.35ppm of PCDF was deodorized in a laboratory deodorizer. The amount of PCB which retained in the oil decreased rapidly with rising of deodorizing temperature. When deodorized at 260-270°C, the remaining PCB in the oil was only 38ppm, namely the residual ratio was 1.6%. Less-chlorinated biphenyls than pentachlorobiphenyl evaporated more rapidly by deodorizing, and consequently the component ratio of penta- to octachlorobiphenyl in the oil increased. When deodorized in the range of 220-270°C, the PCB pattern became similar to those obtained from Kanemi rice oils that caused the “Yusho. ” PCDF in the oil also decreased by deodorizing as well as PCB, but in lesser extent. At the same time, tri- and tetra-chlorodibenzofuran decreased, and the component ratio of penta- and hexa-chlorodibenzofuran in the oil increased. On the other hand, it became clear that the composition and concentration of PCQ in the oil did not change by deodbrizing. Consequently, the ratios of PCQ/PCB and PCDF/PCB in the oil increased rapidly and reached gradually to the status obtained from Kanemi rice oil. It was concluded that PCB used as the thermotransfer medium, which contained PCQ and PCDF, leaked out into Kanemi rice oil in the deodorizer, and thereafter the ratios of PCQ/PCB and PCDF/PCB in the oil might become extraordinarily high by deodorizing.
The effects of antioxidants, dibutyl hydroxy toluene (BHT) and butyl hydroxy anisol (BHA), on lipid peroxidation by superoxide radicals (O-2) were examined using isolated rat liver mitochondria. Superoxide radicals were generated with xanthine and xanthine oxidase. The concentration of O-2 generated with this system was depentent on the concentration of xanthine oxidase. The superoxide radicals reduced Fe3+ to Fe2+, which induced lipid peroxidation. BHT inhibited lipid peroxidation by 100% at a concentration of 1×10-7M and BHA by 45% at the same concentration. BHT and BHA also inhibited the reduction of nitro-blue tetrazolium by inhibiting O-2-dependent reduction of Fe3+ as a result of O-2 trapping by these antioxidants.
When diethylamine (DEA) was reacted with sodium nitrite at pH 3 in the presence and absence of ethanol, glucose or sucrose, followed by alkalization with sodium hydroxide to terminate the reaction, nitrosodiethylamine (NDEA) formation was stimulated by the addition of ethanol, glucose or sucrose. However, these compounds had no effect on NDEA formation when the reaction was terminated by the addition of sulfamic acid. Further, when the mixed solution of sodium nitrite and ethanol, glucose or sucrose was first acidified to pH 3, next alkalized to pH 13, and then combined with DEA, NDEA was formed in proportion to the concentration of ethanol, glucose or sucrose. NDEA was also formed in the reaction of DEA and ethylnitrite in basic medium. It can be probably postulated that the corresponding nitrous acid ester is formed from sodium nitrite and ethanol, glucose or sucrose in acidic medium and nitrosates DEA in alkaline medium. It should be noted that apparent stimulation occurs in nitrosation of secondary amines in the presence of compounds having alcoholic hydroxyl groups when reaction is terminated by alkalization.
Reperesentative fungi were isolated from preharvested and freshly harvested barley and wheat grains of eleven prefectures located in the Southern Japan, and studied on ability to produce several Fusaria-toxins in culture media and rice grains. Predominant types of 106 isolates belonged to the species Fusarium graminearum. Incidences of fungal isolates revealing lethal toxicity for mouse and skin necrotization for rats were 22.6% and 34.9%, respectively. The occurrence of Fusaria-toxin producing strains was 39.6% for 12, 13-epoxytrichothecenes, 34.9% for butenolide (4-acetamido-4-hydroxy-2-butenic acid γ-lactone) and 16.3% for zearalenone [6- (10-hydroxy-6-oxo-trans-1-undecenyl) -β-resorcylic acid-lactone], respectively. About half of these toxigenic strains showed the ability to produce two or more mycotoxins simultaneously. The majority of 12, 13-epoxytrichothecene-producing strains of F. graminearum metabolized either deoxynivalenols or nivalenols. These data provide conclusive evidence for the infection of field barley and wheat of the Southern Japan by different strains of F. graminearum which produced either deoxynivalenols or nivalenols.
It is valuable to survey aflatoxins as contaminant in dairy products. An analytical method to determine aflatoxins in high level recovery was studied. Aflatoxins were extracted from dairy products with the solvent of water-acetone system, protein in the extract was removed with 20% lead acetate solution and fat was washed with n-hexane. Afters the extracts in the solvent were transferred to chloroform, the chloroform layer was chromatographed on a silica gel column using methanol-chloroform (3: 97) as developing solvent. The collected eluate containing aflatoxins was evaporated to dryness and the residue was treated by thin-layer chromstography after dissolving in a small amount of chloroform. Thin-layer chromatography was performed applying silica gel plate and acetone-chloroform (1: 9) (for separation of aflatoxin B1, B2, G1 and G2), 2-propanol-acetone-chloroform (5: 10: 85) (for separation of aflatoxin M1) as developing solvent. A fluorodensitometer was used for quantitative analysis. For chemical confirmation method of aflatoxin M1 positive sample, the derivatives prepared with trifluoroacetate, acetate and hemiacetal were used. The recoveries on each average were 86% aflatoxin B1, 99% B2, 69% G1, 89% G2 and 102% M1 from the artificially contaminated dairy products were obtained. Using of the metbod, 113 modified powdered milk, 16 skim milk powder, 13 raw cream, 56 condensed milk and 83 cheese in commercial base were analysed. Aflatoxin M1 was detected in 17 natural cheese at the level of 0.2-1.3ppb.
Sporulation and enterotoxin production of food poisoning strains of Clostridium. perfringens type A in sporulation media containing carbohydrates were investigated. A slightly modified Duncan and Strong sporulation medium (BM1) and one without soluble starch (BM2) were employed as basal media. BM1 consisted of proteose peptone (1.8%), yeast extract (0.2%), sodium thioglycolate (0.05%), dibasic sodium phosphate (Na2HPO4·12H2O, 1.2%) and soluble starch (0.4%). 1. From our stock cultures involved in food poisoning outbreaks, strain NCTC8239 with a normally high sporulation frequency and strain A76 with a low sporulation frequency were chosen and the effect of carbohydrate on sporulation and enterotoxin production of those strains was compared with that of soluble starch. Results were as follows: (a) Strain NCTC8239. Fructose and raffinose (+, more effective than soluble starch), lactose and galactose (±), glucose and sucrose (-, less effective than soluble starch); (b) Strain A76. Fructose, galactose, raffinose and sucrose (+), lactose (±), glucose (-). 2. Each of strains NCTC8239, NCTC8798, S79, A75 and A76 showed approximately the same level in spore numbers in BM2 supplemented by galactose or fructose. As to the amount of enterotoxin determined, however, fructose was more effective than galactose. All strains tested produced more than 24μg/ml of enterotoxin in BM2 containing fructose at 1%. 3. The pH value of the final cultures in BM1 was between 5.1 and 6.6, where a satisfactory amount of enterotoxin was determined. But, a maximum in enterotoxin production in BM1 and BM2 supplemented by a carbohydrate other than glucose was obtained when the pH value of the final culture dropped to between 5 and 6. This range of pH value was easily achieved by reducing the concentration of glucose, but no detectable amount of enterotoxin was yielded in the glucose-containing media. Increasing the concentration of soluble starch in BM2 up to 1.6% did not always result in an increase in the amount of enterotoxin produced.
For the rapid determination of tin in canned juice, an improved oxidized hematoxylin method has been investigated. Sample was prepared by digesting 1ml of canned juice with a mixture of sulfuric acid-nitric acid. To 0.2-2.0ml of sample, each 0.1ml of 10% tartaric acid and a drop of 1% phenolphthalein were added. After neutralizing, 2ml of 1% arabic gum were further added. The solution was diluted to 15ml with water, and 5ml of 0.3% improved oxidized hematoxylin reagent was added and mixed well. The solution was allowed to stand for 40min at room temperature, and then was further diluted to 40ml with 0.5% sulfuric acid. The absorbance of the solution was determined at 560nm of the wave length against the reagent blank. Under the condition described above, it was found that tin content in some kinds of canned juice could be determined with recovery 94-110% and coefficient variation about 5%.
There was no report on a method for the determination of bromide in fish jelly products, so the authors experimented by the following method. Sample was homogenized with water and filled up to a constant volume. After centrifugation, the supernatant was filtered and a portion of filtrate was ashed in the presence of sodium hydroxide pellets. The ash was dissolved in water and neutralized with 6N sulfuric acid. The bromide in neutralized solution was oxidized with sodium hypochlorite to bromate which was debermined iodmetrically after removal of the excess sodium hypochlorite by the addition of sodium formate. The recoveries of bromide were 101 and 102% in Sasakamaboko and Itatsuki-kamaboko, respectively.