Kenji Tanno

Quantitative determination of marine toxins associated with diarrhetic shellfish poisoning by liquid chromatography coupled with mass spectrometry

Quantitative determination by liquid chromatography (LC) coupled with mass spectrometry (MS) was achieved for the following 10 toxins found in association with diarrhetic shellfish poisoning: okadaic acid (OA), dinophysistoxin-1 (DTX1), 7-O-palmitoylokadaic acid (palOA), 7-O-palmitoyldinophysistoxin-1 (pa1DTX1), pectenotoxin-1 (PTX1), pectenotoxin-2 (PTX2), pectenotoxin-2 seco acid (PTX2SA), pectenotoxin-6 (PTX6), yessotoxin (YTX), and 45-hydroxyyessotoxin (YTXOH). Toxins in 2 g of the adductor muscle or the digestive glands of scallops, Patinopecten yessoensis, were extracted with 18 ml of methanol-water (9:1, v/v), freed of polar contaminants by partition between chloroform and water, and treated by solid-phase extraction on a silica cartridge column. Samples containing YTXOH were purified separately on a buffered reversed-phase column. Chromatographic separation was achieved by the following combinations of columns and mobile phases: a Symmetry C18 column with acetonitrile-0.05% acetic acid (7:3, v/v) for OA, DTX1, PTX6 and PTX2SA; a Develosil ODS column with the same mobile phase for PTX1 and PTX2; a Capcellpak column with methanol-2.5% acetic acid (98:2, v/v) for palOA and palDTX1; and an Inertsil ODS column with methanol-0.2 M ammonium acetate (8:2, v/v) for YTX and YTXOH. Carboxylic acid toxins were selectively monitored on [M-H]- ions, sulfated toxins on [M-Na]-ions, and neutral toxins on [M+NH4]+ ions. Average recoveries of the toxins spiked to tissue homogenates ranged from 70 to 134%. Detection limits in the muscle ranged from 5 to 40 ng/g and those in the digestive glands from 10 to 80 ng/g.

Studies on Keeping Quality and Freshness of the Marine Products

戦後食糧事情の厳しかった時代は魚介類の鮮度判定および保鮮技術に関する研究が多く行われた。その後コールドチェーンの一応の確立によって防腐問題の解決が図られ、鮮度問題は解決されたかにみなされてきたが、一方で品質保持に関して種々な改良がなされ、急速・極低温冷凍技術が発達するとともに、氷温貯蔵技術の進歩がもたらされ、鮮度判定法としても従来のVBN判定からATP関連物質判定へと発展してきた。しかし今日200海里時代に入り、わが国の漁塞が著しい制約を受けるに及んで、水産資源の有限性に対する認識が昂まるとともに、水産資源の有効利用技術の開発が社会的に要請されるようになった。そのため、近時登場した鮮度保持剤を用いた沖締技術および保鮮包装剤について、それらの効果を検討しようとする研究を実施したので、報告する。 試験魚介類として、カキ、エビ、イワシ、サバ、タイ等を用い、天然海水を対照として塩素およびオゾン処理海水、ピチピチ(トーユー)添加海水(PP)、それらとともにゼオミック(シナネンニューセラ)袋(SP)による保鮮効果を細菌数(一般細菌数、大腸菌数、低温細菌数)、K値、およびIMP濃度、さらにパネルテストによって判定を行った。 クロダイを氷蔵した場合、15日迄の官能検査でPPが最高であり、5℃で貯蔵したものではK値およびIMPともSPおよびO3が良く、イワシ、サバではK値およびIMPともPPは対照より優れていた。カキでは氷蔵下で9日迄官能検愛で、殻付きでもPPは対照に勝り、K値からもPPは対照よりも良い結果が得られた。エビではPPがK値、IMPとも最高であり、一般細菌数、低温細菌数からみるとSPが最も優れていた。また官能検査での臭気からPPが最も良い結果を得た。

Microbicidal Effects of Iodine-Glycin Complex Solution

The microbicidal effects of iodine-glycin complex solution (IG), which contains potassium tetraglycin triiodide (16.0% as active iodine at final conc.) and phosphoric acid (8.0% at final conc.), were examined on various microbes.Minimum microbicidal concentrations (as active iodine) of IG, acting within 10min, were 4.0-8.0ppm for Gram-negative bacteria, 3.0-7.0ppm for Gram-positive bacteria, 1800-4000ppm for bacterial spores and 2.0-160ppm for fungi.The fungicidal effects of IG on Aspergillus niger were compared with those of six kinds of commercial disinfectants. The effects of IG were comparable or superior, and no surviving spores were detected in the solution by the pour-plating culture method when the spores were suspended (ca. 104/ml) in 2000-fold dilution of IG for 10min.

Analytical Methods for Residues of Macrolides in the Muscle and Liver of Swine

Analytical methods for macrolide antibiotics (Macs.) in the muscle and liver of swine were examined.Tylosin (TS), erythromycin (EM), spiramycin (SP), oleandomycin (OM) and kitasamycin (KT) were well extracted with methyl alcohol after deproteinization by means of salt solutions, then adsorbed on an Amberlite XAD-2 resin column and eluted with methyl alcohol. The eluate was concentrated to dryness and dissolved in phosphate buffer (pH 8.0) to prepare a test solution. The cup plating method with Micrococcus luteus as the test organism was employed for the assay, and the average recoveries were more than 93.2% and 92.5% from muscle and liver, respectively. As little as 0.05μg/g (TS, SP, OM, KT) or 0.01μg/g (EM) was detectable.The extraction and the column chromatography were carried out on samples to which other antibiotics had been added in order to check the specificity of the present method. Chlortetracycline (5.0μg/g), fradiomycin (5.0μg/g), kanamycin (5.0μg/g), monensin (5.0μg/g) and colistin (5.0μg/g) showed no inhibition zone in the cup plating method, but bacitracin (5.0μg/g), ampicillin (5.0μg/g) and oxytetracycline (5.0μg/g) showed an inhibition zone.Bioautography was suitable for both separation and confirmation of the identity of Macs.