Application of a Swab Sampling Method for the Detection of Norovirus and Rotavirus on Artificially Contaminated Food and Environmental Surfaces

Noroviruses and rotaviruses are the leading causes of non-bacterial gastroenteritis in humans worldwide. Virus-contaminated food and surfaces represent an important risk to public health. However, established detection methods for the viruses in food products are laborious and time-consuming. Here, we describe a detailed swabbing protocol combined with real-time RT-PCR for norovirus and rotavirus detection on artificially contaminated food and environmental surfaces. Recovery rates between 2 and 78% for norovirus and between 8 and 42% for rotavirus were determined for contaminated food surfaces of apple, pepper, cooked ham and salami. From contaminated environmental surfaces (stainless steel, ceramic plate, polyethylene, wood), recovery rates between 26 and 52% (norovirus) and between 10 and 58% (rotavirus) were determined. The results demonstrate the suitability of the swab sample method for virus detection on food and environmental surfaces. Compared to other methods, it is easy to perform and significantly time-saving, predestining it for routine testing.     

Environmental impact of packaging and food losses in a life cycle perspective: a comparative analysis of five food items

The environmental concern and development issues regarding packaging has for 20 years to a high extent been on packaging when it has become waste. To reduce the environmental impact from the whole food packaging system it is also important to develop the packaging’s ability to reduce food waste. In some cases it may be necessary to increase the environmental impact of packaging in order to reduce food waste. In this paper, the environmental impact of packaging and food losses and the balance between the two has been examined for five different food items. The results show that packaging’s that reduce food waste can be an important tool to reduce the total environmental impact, even if there is an increase in impact from the packaging itself. This is especially true for food items where the environmental impact of the food is high relative the packaging, for example cheese, and for food items with high losses, for example bread. It is important to analyse the risk of increasing food losses when packaging design changes, for example, when the aim is less packaging material, which is the main intention of the packaging and packaging waste directive of the European Union.     

国内外“食”旅游:“Food Tourism”“美食旅游”“饮食旅游”研究比较

基于文献研究法,对国内外1996—2020年721篇文献进行了梳理、归纳与总结,从年度载文量、来源期刊类型、基金项目资助等入手,比较了国内外“食”旅游:“Food Tourism”“美食旅游”“饮食旅游”的研究现状、热点及进展。结果表明:①国外“食”旅游研究已进入成熟阶段,国内正处拓展阶段。②国内外均采用定性与定量相结合的研究方法,国内以定性分析为主,而定量方法相对简单,国外定量方法趋于多元化、复杂化。③国内学者对“美食旅游”“饮食旅游”分别进行了研究。④文献研究得知,韩国“食”旅游研究对全球“食”旅游研究贡献巨大。     

Problems associated with ecological assessment of packaging

Current trends in the development of the world packaging market and the place of ecological tendencies in them suggest the need to analyse the present status of studies on the ecological assessment of packaging materials and packaging. The aim of this study is to present some aspects of ecological assessment of packaging. The methods and criteria of ecological assessment of packaging, including Life Cycle Analysis (LCA) and ecological classification of packaging proposed by COBRO (Polish Packaging Research and Development Centre) in Warsaw were used. The considerations presented in the paper related to the general assumptions of ecological assessment of packaging materials and packaging point to the complexity of the problem and, at the same time, to the immediate interest and importance of studies in this field, particularly in terms of implementing a specific environmental protection policy.     

我国包装废物的分类收集模式

针对塑料类、纸类和金属类等典型包装废物,采用3种包装废物分类收集模式,并在3个居民小区进行示范. 3种分类收集模式为:①自然状态;②在小区进行分类收集的宣传教育;③在宣传教育的同时由专业人员对小区生活垃圾进行分类. 采用物质流分析的跟踪观察法,通过问卷调查、现场采样和入户采访,对不同模式下各类包装废物的产生量、回收量与回收率等废物流数据进行统计,得到包装废物从产生、回收到再利用和最终处置的物流分析图. 结果表明:自然状态下包装废物也有一定的回收率,即我国现有的回收体系对包装废物的分类收集有一定的效果;不同类型包装废物的主要回收环节不同,纸类和金属类包装废物在家庭的回收率较高,而塑料类包装废物的回收主要依赖社会人员分拣;辅以宣传教育等方式,回收价值低、分类收集难度大的包装废物也能得到有效回收.      

Modelling predation by transient leopard seals for an ecosystem-based management of Southern Ocean fisheries

Correctly quantifying the impacts of rare apex marine predators is essential to ecosystem-based approaches to fisheries management, where harvesting must be sustainable for targeted species and their dependent predators. This requires modelling the uncertainty in such processes as predator life history, seasonal abundance and movement, size-based predation, energetic requirements, and prey vulnerability. We combined these uncertainties to evaluate the predatory impact of transient leopard seals on a community of mesopredators (seals and penguins) and their prey at South Georgia, and assess the implications for an ecosystem-based management. The mesopredators are highly dependent on Antarctic krill and icefish, which are targeted by regional fisheries. We used a state-space formulation to combine (1) a mark-recapture open-population model and individual identification data to assess seasonally variable leopard seal arrival and departure dates, numbers, and residency times; (2) a size-based bioenergetic model; and (3) a size-based prey choice model from a diet analysis. Our models indicated that prey choice and consumption reflected seasonal changes in leopard seal population size and structure, size-selective predation and prey vulnerability. A population of 104 (90–125) leopard seals, of which 64% were juveniles, consumed less than 2% of the Antarctic fur seal pup production of the area (50% of total ingested energy, IE), but ca. 12–16% of the local gentoo penguin population (20% IE). Antarctic krill (28% IE) were the only observed food of leopard seal pups and supplemented the diet of older individuals. Direct impacts on krill and fish were negligible, but the “escapement” due to leopard seal predation on fur seal pups and penguins could be significant for the mackerel icefish fishery at South Georgia. These results suggest that: (1) rare apex predators like leopard seals may control, and may depend on, populations of mesopredators dependent on prey species targeted by fisheries; and (2) predatory impacts and community control may vary throughout the predator's geographic range, and differ across ecosystems and management areas, depending on the seasonal abundance of the prey and the predator's dispersal movements. This understanding is important to integrate the predator needs as natural mortality of its prey in models to set prey catch limits for fisheries. Reliable estimates of the variability of these needs are essential for a precautionary interpretation in the context of an ecosystem-based management.     

Adaptations in a hierarchical food web of southeastern Lake Michigan

Two issues in ecological network theory are: (1) how to construct an ecological network model and (2) how do entire networks (as opposed to individual species) adapt to changing conditions? We present a novel method for constructing an ecological network model for the food web of southeastern Lake Michigan (USA) and we identify changes in key system properties that are large relative to their uncertainty as this ecological network adapts from one time point to a second time point in response to multiple perturbations. To construct our food web for southeastern Lake Michigan, we followed the list of seven recommendations outlined in Cohen et al. [Cohen, J.E., et al., 1993. Improving food webs. Ecology 74, 252–258] for improving food webs. We explored two inter-related extensions of hierarchical system theory with our food web; the first one was that subsystems react to perturbations independently in the short-term and the second one was that a system's properties change at a slower rate than its subsystems’ properties. We used Shannon's equations to provide quantitative versions of the basic food web properties: number of prey, number of predators, number of feeding links, and connectance (or density). We then compared these properties between the two time-periods by developing distributions of each property for each time period that took uncertainty about the property into account. We compared these distributions, and concluded that non-overlapping distributions indicated changes in these properties that were large relative to their uncertainty. Two subsystems were identified within our food web system structure (p < 0.001). One subsystem had more non-overlapping distributions in food web properties between Time 1 and Time 2 than the other subsystem. The overall system had all overlapping distributions in food web properties between Time 1 and Time 2. These results supported both extensions of hierarchical systems theory. Interestingly, the subsystem with more non-overlapping distributions in food web properties was the subsystem that contained primarily benthic taxa, contrary to expectations that the identified major perturbations (lower phosphorous inputs and invasive species) would more greatly affect the subsystem containing primarily pelagic taxa. Future food-web research should employ rigorous statistical analysis and incorporate uncertainty in food web properties for a better understanding of how ecological networks adapt.     

我国塑料包装废物的产生和回收特性及管理对策

通过现场调查和资料调研,分析了塑料包装废物的流向和环境特征,总结了塑料包装废物回收的基本特点和经验教训,论述了塑料包装废物回收模式特点,深入分析了回收过程中存在的问题,并提出了加强塑料包装废物回收的管理对策. 结果表明:塑料包装是塑料制品中的重要构成部分,由于质量轻、回收体积大,不易回收,我国每年产生大量的塑料包装废物,城市生活垃圾填埋场成为塑料包装废物的主要流向和污染源. 目前我国塑料包装废物回收依托的是进城务工的个体回收者,与现阶段的国情相符合. 塑料污染问题不是短期内能解决的,必须采取长期的综合管理对策,如进行源头减量化、制定鼓励回收利用的经济政策、采取适宜的无害化处置方式等.      

Modeling individual and population dynamics in a consumer–resource system: Behavior under food limitation and crowding and the effect on population cycling in Daphnia

In population modeling, a considerable level of complexity is often required to provide trustworthy results, comparable with field observations. By assuring sufficient detail at the individual level while preserving the potential to explore the consequences at higher levels, individual-based modeling may thus provide a useful tool to investigate dynamics at different levels of organization. Still, population dynamics resulting from such models are often at odds with observations from the field. This may be partly caused by a lack of focus on the individual dynamics under conditions of food stress and starvation. I developed a physiologically structured, individual-based simulation model to investigate life history of Daphnia and its effect on population dynamics in response to the productivity of the system. In verifying model behavior with available literature data on life history and physiology, I paid special attention to the dynamics of food intake and the verification of individual level results under conditions of food limitation and starvation. I show that the maximum filtering rates under low food levels used in the current model are much closer to measured filtering rates than the ones used in other models. Being consistent with results on physiology and life history from experiments at a wide range of food availability (including starvation), the model generates low amplitude or high amplitude population density cycles depending on the productivity of the system, as observed in field and experimental populations of Daphnia and with the minimum population densities being one to two orders of magnitude lower in the high amplitude than in the low amplitude cycles. To generate results which are not only qualitatively but also quantitatively comparable to experimental and field observations, however, a crowding effect on the filtering response has to be incorporated in the model.     

Bioconcentration factors of mercury by Parasol Mushroom (Macrolepiota procera)

To examine bioconcentration factors (BCFs) of mercury by Parasol Mushroom (Macrolepiota procera) roughly similarly sized (a cap diameter) fruiting bodies of this fungus and underlying soil (0–10 cm) samples were collected at 15 sites in Poland between 1995 and 2003. The total mercury content of the individual caps and stipes of Parasol Mushroom ranged from 0.05 to 22 mg Hg/kg dry matter (d.m.) and from 0.05 to 20 mg Hg/kg d.m., while the means were from 1.1 to 8.4 mg Hg/kg d.m. and from 0.83 to 6.8 mg Hg/kg d.m., respectively. The caps generally contained higher concentrations of mercury when compared to stipes, and the means of the cap to stipe mercury concentration quotient ranged from 1.3 to 4.6. The range of mercury concentration in topsoil samples collected at the sites where the fruiting bodies were collected was from 0.01 to 0.54 mg/g d.m. (means ranged from 0.022 to 0.36 mg/g d.m.). The BCFs factors for total mercury varied from 0.52 to 470 for individual caps and 0.52 to 360 for stipes, while average values, depending on the site, were from 16 to 220 and from 7.6 to 130 for caps and stipes, respectively.