水産魚介類の品質および鮮度維持に関する研究

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。In order to keep the quality and freshness of the fishery products, various treatments were studied on black sea bream (Acanthopagrus schlegeli) and shrimp (Trachypenaeus curvirostris) stored in ice and at 5°C, mackerel (Scomber japonicus) and sardine (Sardinqs melatzosticta) stored at 5°C, and oyster (Crassostrea gigas) in shucked and unshucked forms stored in ice and at 5°C. In general, among the samples packed by usual polyethylene bags, samples treated by 0.34000f modified amino preservating agent (called Pichi-Pichi, PP) have lower K-value and higher IMP content. The ability of PP to suppress the illcreasing rate of K-value (IRK) and to restrain decreasing rate of IMP (DRI) was slightly higher than saturated ozone treatment, higher than chlorinated treatment (0.04 ppm) and control. Samples packed by laminated-Ag-zeolite polyethylene bags (Zeomic) have lower bacterial counts, IRK and DRI than usual one

Population structure of Escherichia coli O26 : H11 with recent and repeated stx2 acquisition in multiple lineages2017

A key virulence factor of enterohaemorrhagic Escherichia coli (EHEC) is the bacteriophage-encoded Shiga toxin (Stx). Stxs are classified into two types, Stx1 and Stx2, and Stx2-producing strains are thought to cause more severe infections than strains producing only Stx1. Although O26:H11 is the second most prevalent EHEC following O157:H7, the majority of O26:H11 strains produce Stx1 alone. However, Stx2-producing O26 strains have increasingly been detected worldwide. Through a large-scale genome analysis, we present a global phylogenetic overview and evolutionary timescale for E. coli O26 : H11. The origin of O26 has been estimated to be 415 years ago. Sequence type 21C1 (ST21C1), one of the two sublineages of ST21, the most predominant O26:H11 lineage worldwide, emerged 213years ago from one of the three ST29 sublineages (ST29C2). The other ST21 lineage (ST21C2) emerged 95 years ago from ST21C1. Increases in population size occurred in the late 20th century for all of the O26 lineages, but most remarkably for ST21C2. Analysis of the distribution of stx2-positive strains revealed the recent and repeated acquisition of the stx2 gene in multiple lineages of O26, both in ST21 and ST29. Other major EHEC virulence genes, such as type III secretion system effector genes and plasmid-encoded virulence genes, were well conserved in ST21 compared to ST29. In addition, more antimicrobial-resistance genes have accumulated in the ST21C1 lineage. Although current attention is focused on several highly virulent ST29 clones that have acquired the stx2 gene, there is also a considerable risk that the ST21 lineage could yield highly virulent clones

National trends in the outcomes of subarachnoid haemorrhage and the prognostic influence of stroke centre capability in Japan: retrospective cohort study

Objectives To examine the national, 6-year trends in in-hospital clinical outcomes of patients with subarachnoid haemorrhage (SAH) who underwent clipping or coiling and the prognostic influence of temporal trends in the Comprehensive Stroke Center (CSC) capabilities on patient outcomes in Japan.Design Retrospective study.Setting Six hundred and thirty-one primary care institutions in Japan.Participants Forty-five thousand and eleven patients with SAH who were urgently hospitalised, identified using the J-ASPECT Diagnosis Procedure Combination database.Primary and secondary outcome measures Annual number of patients with SAH who remained untreated, or who received clipping or coiling, in-hospital mortality and poor functional outcomes (modified Rankin Scale: 3–6) at discharge. Each CSC was assessed using a validated scoring system (CSC score: 1–25 points).Results In the overall cohort, in-hospital mortality decreased (year for trend, OR (95% CI): 0.97 (0.96 to 0.99)), while the proportion of poor functional outcomes remained unchanged (1.00 (0.98 to 1.02)). The proportion of patients who underwent clipping gradually decreased from 46.6% to 38.5%, while that of those who received coiling and those left untreated gradually increased from 16.9% to 22.6% and 35.4% to 38%, respectively. In-hospital mortality of coiled (0.94 (0.89 to 0.98)) and untreated (0.93 (0.90 to 0.96)) patients decreased, whereas that of clipped patients remained stable. CSC score improvement was associated with increased use of coiling (per 1-point increase, 1.14 (1.08 to 1.20)) but not with short-term patient outcomes regardless of treatment modality.Conclusions The 6-year trends indicated lower in-hospital mortality for patients with SAH (attributable to better outcomes), increased use of coiling and multidisciplinary care for untreated patients. Further increasing CSC capabilities may improve overall outcomes, mainly by increasing the use of coiling. Additional studies are necessary to determine the effect of confounders such as aneurysm complexity on outcomes of clipped patients in the modern endovascular era