Agroenvironmental determinants associated with the presence of antimicrobial-resistant Escherichia coli in beach waters in Quebec, Canada     

Turgeon P  Michel P  Levallois P  Chevalier P  Daignault D  Crago B  Irwin R  McEwen SA  Neumann NF  Louie M 《Zoonoses and public health》2011,58(6):432-439

Exposure to microorganisms resistant to antimicrobials may constitute a health risk to human populations. It is believed that one route of exposure occurs when people engage in recreational activities in water contaminated with these microorganisms. The main objective of this study was to explore population-level and environmental determinants specifically associated with the presence of antimicrobial resistant (AMR) generic Escherichia coli isolated from recreational waters sampled from beaches located in southern Quebec, Canada. Water samples originated from the Quebec provincial beach surveillance program for the summers of 2004 and 2005. This study focused on three classes of determinants, namely: agricultural, population-level and beach characteristics for a total of 19 specific factors. The study was designed as a retrospective observational analysis and factors were assessed using logistic regression methods. From the multivariable analysis, the data suggested that the percentage of land used for spreading liquid manure was a significant factor associated with the presence of AMR E. coli (OR=27.73). Conceptually, broad factors potentially influencing the presence of AMR bacteria in water must be assessed specifically in addition to factors associated with general microbial contamination. Presence of AMR E. coli in recreational waters from beaches in southern Quebec may represent a risk for people engaging in water activities and this study provides preliminary evidence that agricultural practices, specifically spreading liquid manure in agricultural lands nearby beaches, may be linked to the contamination of these waters by AMR E. coli.  相似文献   

Determination of aflatoxin M1 in milk by liquid chromatography with fluorescence detection     

H Cohen  M Lapointe  J M Fremy 《Journal of the Association of Official Analytical Chemists》1984,67(1):49-51

A liquid chromatographic (LC) method is proposed for the determination of aflatoxin M1 in milk. The method was successfully applied to both liquid whole and skim milk and also whole and skim milk powder. The samples are initially extracted with acetonitrile-water followed by purification using a silica gel cartridge and a C18 cartridge. Final analysis by LC was achieved using a radial compression module equipped with a 5 micron C18 column and a fluorescence detector. The method was successfully applied to samples at levels of 10 to 0.08 ppb added aflatoxin M1 with recoveries in the range of 70-98%.  相似文献   

Book reviews     

Lloyd  R.  Benarie  Michel  Kallend  Anthony S.  Kinsman  John D.  Hungspreugs  Manuwadi  Lusis  M.  Kohn  Robert E. 《Water, air, and soil pollution》1989,43(3-4):425-425

Water, Air, &; Soil Pollution -  相似文献   

Book reviews     

Michel Benarie  G. F. Humphrey  T. Viraraghavan 《Water, air, and soil pollution》1993,71(1-2):195-200

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Aroma extracts from oyster Crassostrea gigas: comparison of two extraction methods.   总被引：1，自引：0，他引：1  

Anne-Laure Pennarun  Carole Prost  Michel Demaimay 《Journal of agricultural and food chemistry》2002,50(2):299-304

The study of the aroma of oysters is of great economic interest in France because it enables their organoleptic quality to be verified. The aim of this study is to optimize the extraction methods of the volatile compounds of oysters Crassostrea gigas in order to obtain an extract with an odor as close as possible to that of the original oysters'. Oyster aroma is rarely studied, and its sensory profile has not been investigated to date. Two extraction methods were studied: vacuum hydrodistillation carried out at 20 degrees C with noncrushed oyster using ultrapure water and dynamic headspace carried out using noncrushed oyster during a 30 min purge. They were compared with regard to their sensory characteristics by a panel of seven judges, all trained in seafood aroma recognition. This study has shown that vacuum hydrodistillation is the better method to obtain an extract closest in aroma to the oyster reference.  相似文献   

Changes in physicochemical characteristics and volatile constituents of strawberry (Cv. Cigaline) during maturation     

Ménager I  Jost M  Aubert C 《Journal of agricultural and food chemistry》2004,52(5):1248-1254

Changes in the volatile composition of strawberries (cv. Cigaline) at six stages of maturity, from 28 to 44 days after anthesis, were investigated over two harvesting seasons. Volatiles were isolated by direct solvent extraction and analyzed by means of GC-FID and GC-MS, with special attention to the quantification of furanones. Firmness, skin color, soluble solids (SS), titratable acidity (TA), SS/TA ratio, organic acids, and sugars were also determined. With increasing maturity, soluble solids, SS/TA ratio, Minolta a value, and levels of sucrose, glucose, fructose, and malic acid increased, whereas Minolta L value, hue angle (), titratable acidity, and levels of citric acid decreased. Furanones and esters were generally not detected before half-red fruits, whereas C(6) compounds were the main compounds in immature fruits. During maturation, levels of these so-called green components decreased drastically, whereas levels of key flavor compounds increased significantly and were closely correlated with skin color development. Maximum volatile production was observed in fully red fruits.  相似文献   

Analysis of two bentonites of enological interest before and after commercial activation by solid Na(2)CO(3)     

Gougeon RD  Soulard M  Miehé-Brendlé J  Chézeau JM  Le Dred R  Jeandet P  Marchal R 《Journal of agricultural and food chemistry》2003,51(14):4096-4100

Two natural calcium-rich bentonites used for the removal of wine proteins, originating from Greece and Turkey, were studied by X-ray diffraction, thermal analysis, and solid state NMR, before and after activation by solid Na(2)CO(3). Exchange of Ca(2+) by Na(+) mainly occurs for cations located at the edge of layers and only weakly for interlayer cations. This Na(2)CO(3) activation process leads to an increased efficiency in the adsorption process of bovine serum albumin (BSA) used as a model protein for both bentonites. A direct correlation is observed between the extent of Ca(2+)/Na(+) exchange, the strength of adsorption of BSA, and the extent of unfolding of BSA backbone.  相似文献   

Comparison of two microalgal diets. 2. Influence on odorant composition and organoleptic qualities of raw oysters (Crassostrea gigas)     

Pennarun AL  Prost C  Haure J  Demaimay M 《Journal of agricultural and food chemistry》2003,51(7):2011-2018

Oyster farming is of real economic interest in France. Oyster farmers attach more and more importance to improving the growth and the quality of their oysters. Some fatty acids known to be aroma precursors originate from microalgae such as Skeletonema costatum and Tahitian isochrysis clone. These microalgae were used to fatten oysters in order to observe their role in the development of oysters' aroma. This study shows that the profile of fatty acids of oysters is influenced by the contribution of fatty acids from the two microalgae (as reported in the first paper in this series: Pennarun, A.-L.; Prost, C.; Haure, J.; Demaimay, M. Comparison of Two Microalgal Diets. 1. Influence on the Biochemical and Fatty Acid Compositions of Raw Oysters (Crassostrea gigas). J. Agric. Food Chem. 2003, 51, 2006-2010 (in this issue)]. As a consequence, a microalgal diet causes changes in oysters' aroma composition. Aroma concentration depends on the content of fatty acids that are aroma precursors in oysters. Some aromas are characteristic of the diet of S. costatum, such as 6-methyl-5-hepten-2-one (ether odor), and others are characteristic of T. isochrysis, such as 3-nonyne (cucumber, marine odor), 6-(E)-nonen-1-ol (green and fresh odor), and 4-ethylbenzaldehyde (aniseed odor). Moreover, the organoleptic qualities (odor, taste, and texture) of oysters are modified by the diet of microalgae.  相似文献   

Comparison of Coleoptera assemblages from a recently burned and unburned black spruce forests of northeastern North America     

Michel Saint-Germain  Pierre Drapeau 《Biological conservation》2004,118(5):583-592

Several insect groups have adapted to fire cycles in boreal forests, and can efficiently use new habitats created by fire. Our study aimed at producing a first characterization of post-fire Coleoptera assemblages of black spruce forests of eastern North America. For two years, we sampled Coleoptera using flight-interception traps in burned stands of contrasting age and structure in a 5097-ha wildfire and in neighbouring unburned mature stands. More than 40 species were exclusively captured in burned stands. Time elapsed since fire and proximity of unburned forests were the most significant parameters affecting Coleoptera assemblages. Stand age and structure had limited effects on assemblage structure; the Scolytid Polygraphus rufipennis Kirby was the only common species to clearly favor older stands. Fire-associated Coleoptera assemblages found in our study area were clearly distinct from those found in similar unburned stands; we should thus be conservative in our management approach concerning recently burned stands.  相似文献   

Soil properties and the macrofauna community in abandoned irrigated rice fields of northeastern Argentina     

Patricia J. Folgarait  Fabien Thomas  Thierry Desjardins  Michel Grimaldi  Ichiro Tayasu  Pierre Curmi  Patrick M. Lavelle 《Biology and Fertility of Soils》2003,38(6):349-357

This study compared soil physical, chemical, and biological characteristics between natural grassland and recently abandoned rice fields in order to identify those variables that might explain the observed increase of Camponotus punctulatus anthills in abandoned rice paddy fields from Northern Argentina. Mainly due to a reduction of macropores and mesopores, overall porosity decreased by around 6% and bulk density was about 7% greater, in the 0- to 10- and 10- to 20-cm layers of the abandoned rice fields. Carbon and nitrogen content from organic matter increased (29% and 41% respectively for the 0- to 20-cm horizon) during cultivation but decreased (38% and 24%) 2 years after the last rice harvest. Forty percent of natural grassland-organic matter and 30% of abandoned rice-organic matter mineralized in less than 2 years. There was a different community structure between the abandoned rice fields and the undisturbed natural grassland and only a 20.6% (i.e. only 19 species from a total of 92) overlap in species composition. The abundance of macrofauna was greater in abandoned rice fields (2,208 individuals m^–2) in comparison to natural grasslands (288 ind m^–2) due to higher densities of small earthworms and Camponotus punctulatus ants; however, the Shannon index showed lower values in comparison to natural grasslands. Earthworms and C. punctulatus in the abandoned rice fields showed a change in their ¹³C signature indicating a switch in diet from natural grassland organic matter (C4) to organic matter from rice (C3). Our results indicate that the effects of rice cultivation practices did not seem to produce any physical or trophic limitations to recolonization by the macrofauna. It seems that changes in overall soil conditions have favored a change in the construction behavior of C. punctulatus which, in combination with population increases, could explain the explosion in number of anthills.  相似文献