Evidence of cross-contamination by Campylobacter spp. of broiler carcasses using genetic characterization of isolates

Campylobacter is recognized as one of the leading cause of gastroenteritis worldwide, and is frequently isolated from the small intestines and ceca microflora of chickens. Twenty-one out of 81 Campylobacter-positive poultry flocks were selected to evaluate the genetic diversity of Campylobacter isolates and to study the distribution of genotypes among flocks. Campylobacter isolates recovered from chicken carcasses and ceca were analyzed by pulsed-field gel electrophoresis (PFGE). Little diversity was found among Campylobacter strains isolated from a given carcass, with a maximum of 2 different genotypes being present. However, at flock level, as many as 4 different profiles were observed. Typing of strains showed that most strains isolated from ceca were similar to those isolated from corresponding broiler carcasses. A total of 39 different macrorestriction profiles were observed, with evidence of Campylobacter cross-contamination among broiler flocks in Quebec slaughterhouses. Surprisingly, some flocks shared related genotypes both with and without sharing similar rearing practices. Existence of such cross-contamination must be considered to in developing strategies to control Campylobacter in chickens, and to avoid bacteria contamination of noncolonized flocks. Further typing studies of Campylobacter found in hatcheries, farm environment, and crates or trucks in Quebec might be helpful in elucidating the kinetics of broiler chicken Campylobacter contamination.     

禽产品安全控制研究进展

在食品安全方面,最重要的发现之一是冷链系统在食品运输中的发展。从那以后,HACCP的采用已经在食品生产业中成为另一项改革,而分子生物学的最新进展使得快速微生物学方法的发展和运用相对于传统的方法来说是一种改革。公众在与食品中细菌传播有关的风险因子方面的知识已得到提高,但对弯曲杆菌的了解仍然很少。在这种情况下,本文将讨论一些细菌诊断工具,细菌收获前后的控制措施和收获后处理方法的优化。     

Influence of Sediment Preservation on Total Mercury and Methylmercury Analyses

Estuarine and riverine sediments from fourlocations showing different sediment structures wereanalysed as fresh, thawed and lyophilised samples fortotal mercury (TotHg) and methylmercury (MeHg)concentrations, and results were compared to addresseffects of sample preservation on Hg speciation. TotHg was measured by cold vapour atomic absorptionspectrometry (CVAAS). MeHg was isolated bydistillation and ion-exchange and analysed by coldvapour atomic fluorescence spectrometry (CVAFS) afterpreconcentration on a gold trap. No loss of TotHg norMeHg due to lyophilisation was found. Concentrationsof TotHg and MeHg respectively ranged from 92 to 267ng g^-1 dw and 1.1 to 2.9 ng g^-1 dw in freshsamples, from 94 to 215 ng g^-1 dw and 1.1 to 2.8ng g^-1 dw in thawed samples, and from 100 to 256ng g^-1 dw and 1.2 to 3.1 ng g^-1 dw inlyophilised samples. Lyophilised samples showedbetter homogeneity and better MeHg analysisreproducibility compared with wet samples.     

Conservation implications of establishment success of the Critically Endangered Twee River redfin ‘Pseudobarbus’ erubescens (Skelton, ) in an artificial impoundment in South Africa

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Fungal biodegradation of a phenylurea herbicide,diuron : structure and toxicity of metabolites

Microbial degradation, organic synthesis and ecotoxicology were used to investigate the fate of diuron after spreading on soils. Quantitative biodegradation assays were performed with fungal strains, showing that diuron was degraded but not entirely mineralized. The modifications observed consisted in demethylation of the terminal nitrogen atom. The identified metabolites were synthesized in sufficient amounts to confirm their structures and determine their non‐target toxicity using four biotests. The two metabolites exhibited higher effects than parent diuron. This limited biodegradability and potential aquatic toxicity suggest that diuron is of higher environmental concern than previously recognized. © 2000 Society of Chemical Industry     

Molecular Mobility in Glassy Bread: A Multispectroscopy Approach

The molecular mobility in low-moisture (<9%, web) white bread was studied as a function of temperature using pulsed-proton nuclear magnetic resonance (NMR), and dielectric and dynamic mechanical spectroscopies. The water was mobile, even in glassy samples. Different processes below glass transition temperature (sub-T_g) were observed, and a relaxation map of the studied system was drawn. These results have been interpreted and extrapolated to suggest that the T_g is not a universal predictive parameter for the physical stability of glassy food.     

Release of atrazine and alachlor from clay-oxamide controlled-release formulations

Controlled-release herbicide formulations have been shown to decrease the leaching potential of several herbicides under laboratory and field conditions. The utility and efficacy of these formulations may be improved by combining several herbicides and a fertilizer source in a single formulation. The objective of these studies was to develop granular alginate formulations that were composed of a combination of the herbicides atrazine and alachlor with the slow-release nitrogen source oxamide (ethanediamide). Controlled release of the herbicides was obtained by addition of selected minerals, including calcium bentonite, fine-grind bentonite, montmorillonite K10, kaolinite and iron (III) oxide. A formulation without clay was used as a comparison. The formulations tested had herbicide active ingredient contents ranging from ∽0·02 to 0·54% and a nitrogen content of 21%. Release of the herbicides was studied by equilibrating the formulations with deionized water on a rotary shaker at 200 rev min^-1 and sampling at regular time intervals up to 104 hours. The minerals used in the different formulations influenced the herbicide active ingredient composition, as well as the release properties of the individual formulations. The atrazine content of the formulations decreased in the order calcium bentonite>fine-grind bentonite>kaolinite>montmorillonite=iron oxide>no clay. For alachlor the content decreased in the order of calcium bentonite>fine-grind bentonite>montmorillonite>iron oxide>kaolinite>no clay. Controlled release of atrazine (i.e. reduction in release rate) varied in the order calcium bentonite>iron oxide>montmorillonite>fine-grind bentonite= kaolinite>no clay, and for alachlor fine-grind bentonite>calcium bentonite>montmorillonite>no clay=kaolinite=iron oxide. A certain percentage of the applied active ingredient of both alachlor and atrazine was not recovered. From 5 to 27% of the active ingredient was not released, with the greatest retention by the bentonite formulations. Release of nitrogen was not strongly influenced by mineral type, although a trend indicated greater release with formulations containing kaolinite. © 1998 SCI     

Incidence of competitors and landscape structure as predictors of woodland-dependent birds

Globally, modification of landscapes for agriculture has had a strong influence on the distribution and abundance of biota. In particular, woodland-dependent birds are under threat across agricultural landscapes in Britain, North America and Australia, with their decline and extirpation attributed to the loss and fragmentation of habitat. Other native species have become over-abundant in response to anthropogenic landscape change and have strong interactive effects on avian assemblage structure. In eastern Australia, the hyper-aggressive noisy miner (Manorina melanocephala) often dominates woodlands in agricultural landscapes through interspecific competition, resulting in declines of species richness of woodland-dependent birds. We aimed to determine the relative influence and importance of interspecific competition, in situ habitat structure and landscape structure for woodland-dependent bird species at the landscape level. We recorded species-specific landscape incidence of woodland-dependent birds in 24 agricultural-woodland mosaics (25 km²) in southern Queensland, Australia. We selected extensively cleared landscapes (10–23 % woodland cover) where fragmentation effects are expected to be greatest. We applied generalised linear models and hierarchical partitioning to quantify the relative importance of the landscape-level incidence of the noisy miner, mistletoe abundance, shrub cover, woodland extent, woodland subdivision and land-use intensity for the incidence of 46 species of woodland birds at the landscape-scale. The landscape-level incidence of the noisy miner was the most important explanatory variable across the assemblage. Both in situ habitat structure and landscape structure were of secondary importance to interspecific aggression, although previous research suggests that the increasing incidence of the noisy miner in fragmented agricultural landscapes is itself a consequence of anthropogenic changes to landscape structure. Species’ responses to fragmentation varied from positive to negative, but complex habitat structure had a consistently positive effect, suggesting in situ restoration of degraded habitats could be a conservation priority. Landscape wide conservation of woodland-dependent bird populations in agricultural landscapes may be more effective if direct management of noisy miner populations is employed, given the strong negative influence of this species on the incidence of woodland-dependent birds among landscapes.     

Multiple progressive piloleiomyomas in a ferret (Mustela putorius furo): a case report

A 2.5‐year‐old ovariectomized female ferret developed multiple progressive linear and raised nodules on the skin. The first lesions occurred on the tail, which was then amputated. Over the following 3 years, additional lesions appeared in the vicinity of the scar and then further rostrally on the flanks and thorax. Histological and immunohistochemical investigation led to a diagnosis of multiple piloleiomyomas. The unique characteristics of this ferret disease are described and compared with those of multiple piloleiomyomas in humans and with those of other cutaneous smooth muscle cell tumours reported in the veterinary literature.