パラオキシ安息香酸のペンチル, ヘキシル, ヘプチル, オクチル, ノニルまたはデシルエステルをリン酸化した水溶性の誘導体, p-alkoxycarbonyl phenyl phos-phateを合成し, 微生物に対する作用を調べた結果, これらはいずれも火落菌に対して強い抗菌作用を有することがわかった.
これらの誘導体は清酒用の防腐剤として利用できるように思われたので, その中からp-heptoxycarbonylphenyl phosphate (PP-7) を選び, 理化学的性質や安定性について検討した.
(1) PP-7では火落菌に対する有効濃度が12.5～50ppmでその抗菌力が強く, サリチル酸に比較して約10倍の抗火落菌作用を示した.
(2) PP-7は清酒, 15%エタノール, 水などに良く溶けるので, 実用的には使いやすい.
(3) 酸性溶液では徐々に加水分解され, パラオキシ安息香酸ヘプチルェステル (P-7) を生成するが, この場合のP-7はPP-7とほぼ同じ抗火落菌作用を示す.
(4) マウス経口投与によるPP-7のLD50は7.6g/kgで, P-7と同様にその毒性はサリチル酸よりも少ない. 以上のことから, PP-7は清酒用またはビール用の新防腐剤として期待される.

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Organotin compounds, such as di-n-butyl tin and di-n-octyl tin derivatives, are effective stabilizers in the manufacture of rigid PVC containers for food packaging use. Certain derivatives, however, have biological activities in food hygienic sense.
The determination of minute amount of di-alkyl tin compounds migrated from container into food-simulating media was successfully carried out by dithizone-extraction and succeeding colorimetric measurement in 1, 2-dichloroethane. Inhibition of heavy metals was eliminated by EDTA-extraction in borate buffer of pH 8.4.
Rigid PVC containers, including different types and concentrations of di-n-alkyl tin stabilizers were prepared, in which Various food-simulated solutions were packed and stored at a temperature of 50°C. The stabilizer migrated from PVC into the solution was determined after aging.
The extent of migration was larger in hydrophobic solution than in hydrophillic media. The extraction of di-n-butyl tin increases with increase of the content formulated in PVC, while di-n-octyl tin was scarcely extracted. Effect of other additives on the migration was observed for di-n-octyl tin-stabilized system in fat-simulated medium.

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In the previous paper the authors reported on the formation and determination method of diethyl carbonate (DEC) in foods. But, the procedure of the method was somewhat complicated and the recovery of DEC was not necessarily complete. In this paper was described the improved method, in which the procedure was made more simple and the recovery ratio of DEC higher than that of the previous method.
The outline of the new determination method is as follows. DEC in the food is extracted with chloroform, and then directly determined by gas chromatogray using diisodecyl phthalate and polyethylene glycol 400 as complex columns and ethylbenzene as an internal substance. The recovery of DEC in foods was as high as 93-98%. At the same time, the stability of DEC in water, ethanol aqueous solution and alcoholic drinks was studied. DEC was stable in alcoholic drinks for at least about one month, but in water decreased to 70-90% of the initial concentration after twenty days.

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In view of the studies on V. parahaemolyticus conducted so far by the present author, the general consideration that all of the organisms occurring in city river-water are brought directly from sea-water environments is thought to be suspectable.
Preliminary experiment indicated that the organisms could be isolated from city river-water which was allowed to stand for 24 hrs at room temperature after its collection in the daytime, and that the isolates could not survive for more than 5 hrs in the sterilized river-water.
In the present study, the similar experiment was carried out with water samples collected in the midnight from a river within the town of Nagasaki. For plating after enrichment cultivation of river water, TCBS-agar medium was employed. Consequently, the similar results (Tables 2 and 3) were obtained. These results suggest that there may be an essential difference in susceptibility to lysis in river-water between the bacterial cells before and after isolation, and lead to the assumption that “specific” V. parahaemolyticus of considerably prolonged survival may be present in natural river-water. On the other hand, it was recognized that the isolation of the organisms from river water was inhibited on BS-broth medium (Table 4). This action appears to be associated with the survival mechanism. It was also confirmed that none of the organism was detected in river water filtered through Millipore filter (Table 5). Therefore, it is unlikely that the survivors were connected with filterable cells which were previously found to occur in the culture of the organisms by the present author. There is no apparent explanation for the occurrence of “specific” V. parahaemolyticus in city river-water at the present time, though it seems possible that the organisms might exist in non-halophilic form in natural river-water before isolation.

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In an attempt to explore better selective medium for E. coli from contaminated foods, dehydration of SMEC medium has been studied.
Procedure for preparation of studied SMEC dehydrated culture medium was as follows;
Composition of the medium in 1L was, heart infusion, 4g; casamino acid, 15g; Ltryptophan, 0.05g; lactose, 5g; K₂HPO₄, 4g; KH₂PO₄, 5g: sodium lauryl sulfate, 0.25g; bile salt, 0.5g and 0.2% BCP, 16ml.
Final pH of the medium was 6.2.
Rehydration is made by suspending 33.8g of the above mentioned dehydrated medium in 1000ml of distilled water and boiling until the medium dissolves completely. Then, 10mg of streptomycin was added after cooling down of the solution to 4-5°C.
After being dispensed into fermentation tubes, tubes were subjected to sterilization at 100°C for 60 minutes.
Through application of SMEC dehydrated culture medium to detection of E. coli from various raw meats, following results have been obtained.
1. SMEC dehydrated medium showed the best agreement with MPN of presumptive test and MPN completed test against E. coli.
2. In the SMEC (at 44.5°C) confirmation test against isolated strain from raw meat, positive rate of E. coli group (including type I, II and III) was 88.6% while that of coliform groups was 7.8%.
Above findings were almost identical with the results observed when the original compounded SMEC medium was employed.

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Determination of cadmium in rice and soil by means of atomic absorption spectroscopy was examined using an APDC-Chloroform extraction system.
An APDC (ammonium pyrrolidinedithiocarbamate) -chelate of cadmium was extracted from the sample solution into chloroform which had seemed unsuitable to a solvent for atomic absorption spectroscopy, followed by direct spraying to a air-hydrogen flame. The flame was quite stable and the background was vanishingly small at 2288 Å (resonance line of cadmium). The proposed method of determination was scarcely subjected to the interference from other metals, because of the excellent solubility of APDC-chelate in chloroform.
Experimental conditions including hollow cathode lamp current, gas pressure and pH of the sample solution etc. were examined and the calibration curve gave a straight line in the range of 0.02-1.0ppm of cadmium. On the basis of these result, a method for determination of cadmium was established and has been proved to be simple, convenient and moreover accurate by practical application to analysis of cadmium in rice and soil.

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A rapid and simple method was devised for the separation and identification of coal-tar dyes in foods by means of partition column chromatography. Outline of the experiments carried out is as follows.
(1) About 1g of the sample was mixed with 4g of silica gel and required amount of anhydrous sodium sulfate.
(2) The mixture was packed in a glass column of 1.4cm in diameter (stoppered with cotton to the bottom of the column), above the adsorbent (alumina: synthetic zeolite 4: 1) of a 10cm layer (see Fig. 1).
(3) The column thus prepared was subjected to partition chromatography by the descending method using the mixture of acetone, isoamyl alcohol, water and methyl cellosolve (6: 5: 5: 2) as a solvent.

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(1) 包装かまぼこ62検体を30°および37°の恒温試験に供しその変敗状況を追求したところ, 気泡発生型変敗, 軟化型変敗, はん紋型変敗の3型に大別できた.
(2) 変敗品からは35株のBacillusが検出されたが9種に同定された. そのうちBacillus subtilis, Bacilluslicheniformisはすべてのものに存在していた.
(3) 気泡発生型変敗品からはBacillus polymyxaが, 軟化型変敗品からはBacillus circulans, Bacillus lich-eniformis, Bacillus subtilisが, またはん紋型変敗品からはBacillus sphaericus, Bacillus licheniformis, Bacillus subtilisが原因菌として検出された.
(4) 分離された細菌はいずれも現在, 包装かまぼこで実施されている殺菌条件に耐えることが判明した.

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ライヘルトマイスル価およびポレンスケ価はそれぞれ一定の条件下で留出する水溶性および不溶性揮発性脂肪酸量を滴定するものであるから, 測定条件によってある程度異なった結果が得られることが考えられる. 純乳脂肪を使用して国際酪農連盟 (IDF) 標準法, A. O. A. C. 公定法および日本薬学会協定法により測定した結果, ライヘルトマイスル価はほぼ一致した値が得られたが, ポレンスケ価では日本薬学会協定法ではやや高い値が得られた. 植物油脂についての測定値はやし油のR. M. W. : 6.4, Pol.: 15.1, パーム核油のR. M. W. : 4.3, Pol.: 7.9, パーム油のR. M. W. : 0.6, Pol.: 0.6, カポック油ではR. M. W. : 0.2, Pol.: 0.6であった.
乳脂肪のライヘルトマイスル価の範囲は24.8以上, ポレンスケ価はライヘルトマイスル価にしたがって2.6～3.7以下 (Table 4参照) と定めるのが適当であると考えられる. 市販バター38種類について, 酢酸フィトステロール試験の成績と比較した結果両法で陽性と判定されたもの7検体, 酢酸フィトステロール試験のみ陽性のもの2検体であった. ライヘルトマイスル価およびポレンスケ価の測定は異種脂肪の検出のための補助的方法として使用することができる.

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1) デ培地に発育した赤変菌252株中, 大腸菌群に属するもの183株 (72.6%), 衛生細菌学でいう大腸菌群に属さない菌 (類似菌) 69株 (27.3%) であった. なお類似菌69株中チトクロムオキシダーゼ陽性株20 (29.0%), 陰性株49 (71.0%) であった.
2) 牛乳, アイスクリームおよびその処理設備からデ培地により分離した大腸菌群183株中E. coliに属するものはわずか8株 (4.4%) にすぎず, その大半はK. cloacae (52.5%) とK. aerogenes I型 (31.7%) でしめられた.
3) 牛乳およびアイスクリームに検出される大腸菌群の汚染源は主としてその充てんならびに包装設備であると推定された.
4) 35°培養のデ培地に赤変集落を形成する菌181株中, 大腸菌群と同定されたものは166株 (91.7%) また25°培養のデ培地に赤変集落を形成する菌71株中, 大腸菌群と同定されたものは17株 (23.9%) であった.
5) 分離大腸菌群183株中, 37°で発育するもの153株 (83.6%), 30°で発育するもの181株 (98.9%), 20°で発育するもの176株 (96.2%) また7°で発育するもの34株 (18.6%) であった.
6) EC test
分離菌252株のEC testの結果はE. coli I型に属する3株が8時間で陽性となり, K. aerogenes I型に属する56株中36株 (64.3%) が18～24時間で陽性となった.

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