Elimination of Listeria monocytogenes in soft and red smear cheeses by irradiation with low energy electrons

Soft and red smear cheeses are frequently contaminated by Listeria monocytogenes , sometimes at relatively high concentration (< 10⁵ CFUg^-1). This bacterium is radiosensitive (D₁₀ value of approximately 0.45 kGy) but irradiation of the whole cheese by X-rays induced off-flavours when the dose exceeded 1.0 kGy. Irradiation could be effective in eliminating L. monocytogenes only from lightly contaminated cheeses (> 10²CFU g^-1).
L. monocytogenes appears only in the rind (where the pH is greater than 6.3) and never grows in the core of the cheese. Under these conditions, a specific irradiation of the rind after ripening, with a low-energy electron beam at relatively high doses (up to 3.0 kGy), allows the total elimination of L. monocytogenes in heavily contaminated samples (10⁵-10⁶ CFU g^-1) without noticeable modifications of the organoleptic properties of the cheese.     

Road Construction and River Pollution in South-West Scotland

During the period 1993–95, four engineering companies were involved in six separate projects entailing the construction of a motorway to replace the existing A74 Glasgow – Carlisle trunk road. The construction contracts were undertaken in a rural part of south-west Scotland. This paper describes (i) the events which led to the serious pollution of rivers, (ii) the prosecution of offenders, and (iii) measures which have been taken to ensure that future road-construction projects in Scotland do not impact upon the aquatic environment.     

一株Kefir源乳酸菌MA2的鉴定及对大鼠肠道菌群的影响

对从西藏Kefir粒中分离出来的乳酸菌MA2进行了形态学、生理生化和16SrDNA分子生物学鉴定,确定其为植物乳杆菌．酸和胆盐耐受性实验显示,植物乳杆菌MA2在pH2．0、胆盐浓度为0．3％的情况下具有较好的耐受能力．动物实验证明,植物乳杆菌MA2显著促进了双歧杆菌和乳酸菌的生长,调节了肠道菌群的平衡,是一株潜在的、具有实际应用价值的益生菌．     

松嫩草地有毒植物资源调查

对松嫩草地有毒植物资源进行了系统调查。据植物分类学统计,该地区共有有毒植物32科72属93种7变种。有毒植物资源丰富,分布广泛,植物区系成分复杂,其多数属具温带性质,在有毒植物东北植物区系地理成分中,长白植物区系占一定优势。     

油田采出水回用试验研究

叙述了采出水通过膜-生物反应器结合微生态菌群技术、反渗透技术进行了实验研究,处理出水达到了回用水指标,并对系统稳定性运行进行了考核。     

Ecological characteristics and management of geothermal systems of the Taupo Volcanic Zone,New Zealand

New Zealand has an array of geothermal systems with distinctive ecological features, with many occurring in the Taupo Volcanic Zone in the Central North Island. Associated with these geothermal features are characteristic geophysical and geochemical components, and distinctive terrestrial and aquatic ecosystems with many attributes that are common across a range of the biotic groups. Zonation amongst vegetation communities is closely related to soil temperature and these associations generally occur in a predictable sequence along the soil temperature gradient. Similarly, clear distinctions in aquatic flora and fauna occur longitudinally downstream from the source of thermal springs and vertically on geyser mounds.     

铁浓度对某铀矿浸铀菌群的影响

微生物堆浸具有技术提高铀的浸出率,缩短生产周期,节省硫酸及氧化剂,降低生产成本,减少对环境所造成的不利影响的优点。某铀矿是我国重要的铀矿山,在2009年之后,该铀矿陆续开展一系列的微生物堆浸实验和生产项目,在文章中,笔者讨论以及分析了不同浓度的亚铁和三价铁对该铀矿中浸铀菌群的影响。结果表明,低浓度的二价铁和高浓度的三价铁都有利于菌群的氧化,并且该铀矿菌群的最适总铁浓度为8 g/L。