Sow H.,Laval University |
Desbiens M.,Ministere de lAgriculture |
Morales-Rayas R.,Laval University |
Ngazoa S.E.,Laval University |
Jean J.,Laval University
Foodborne Pathogens and Disease | Year: 2011
The effectiveness of different thermal treatments for inactivating two viruses in clams was evaluated. Soft-shell clam digestive glands experimentally contaminated with hepatitis A virus (HAV) or murine norovirus (MNV) were heated for 90, 180, or 300 seconds at 85°C or 90°C in glass vials or plastic bags with 200 g of soft-shell clam meat. Inactivation was measured by plaque assay and real-time reverse-transcription (RT)-polymerase chain reaction assay. Measured inactivation was similar using both assays. The 90°C for 90 seconds treatment reduced MNV-1 titer by 3.33 log cycles and HAV by 2.66 log cycles. At 90°C for 180 seconds, both MNV-1 and HAV were completely inactivated (titer reduced by 5.47 log cycles) in glass vials. In the presence of clam meat as well, HAV inactivation was complete at 90°C for 180 seconds. In general, HAV was more resistant to heat treatment than MNV-1, suggesting that it would require a more severe treatment than human norovirus for inactivation in soft-shell clams. The results of the present study should contribute to the development of strategies for controlling the spread of enteric viral illness via shellfish. Copyright © 2011, Mary Ann Liebert, Inc.
Mabit L.,International Atomic Energy Agency |
Bernard C.,Ministere de lAgriculture
Earth Surface Processes and Landforms | Year: 2010
Soil erosion induces soil redistribution within the landscape and thus contributes to the spatial variability of soil quality. This study complements a previous experimentation initiated by the authors focusing on soil redistribution as a result of soil erosion, as indicated by caesium-137 (137Cs) measurements, in a small agricultural field in Canada.The spatial variability of soil organic matter (SOM) was characterized using geostatistics, which consider the randomized and structured nature of spatial variables and the spatial distribution of the samples. The spatial correlation of SOM (in percentages) patterns in the topsoil was established taking into account the spatial structure present in the data. A significant autocorrelation and reliable variograms were found with a R2 ≥ 0·9, thus demonstrating a strong spatial dependence. Ordinary Kriging (OK) interpolation provided the best cross validation (r2 = 0·35). OK and inverse distance weighting power two (IDW2) interpolation approaches produced similar estimates of the total SOM content of the topsoil (0-20 cm) of the experimental field, i.e. 211 and 213 tonnes, respectively. However, the two approaches produced differences in the spatial distribution patterns and the relative magnitude of some SOM content classes. The spatialization of SOM and soil redistribution variability - as evidenced by 137Cs measurements - is a first step towards the assessment of the impact of soil erosion on SOM losses to recommend conservation measures. © 2009 John Wiley & Sons, Ltd.
Gaulin C.,Ministere de la Sante et des Services Sociaux |
Ramsay D.,Ministere de lAgriculture |
Bekal S.,Laboratoire Of Sante Publique Du Quebec
Journal of Food Protection | Year: 2012
A major Listeria monocytogenes outbreak occurred in the province of Quebec, Canada, in 2008, involving a strain of L. monocytogenes (LM P93) characterized by pulsed-field gel electrophoresis (PFGE) and associated with the consumption of pasteurized milk cheese. This report describes the results of the ensuing investigation. All individuals affected with LM P93 across the province were interviewed with a standardized questionnaire. Microbiological and environmental investigations were conducted by the Quebec's Food Inspection Branch of Ministére de l'Agriculture, des Pêcheries et de l'Alimentation du Québec among retailers and cheese plants involved in the outbreak. Between 8 June and 31 December 2008, 38 confirmed cases of LM P93 were reported to public health authorities, including 16 maternal-neonatal cases (14 pregnant women, and two babies born to asymptomatic mothers). The traceback of many brands of cheese that tested positive for LM P93 collected from retailers identified two cheese plants contaminated by L. monocytogenes strains on 3 and 4 September. PFGE profiles became available for both plants on 8 September, and confirmed that a single plant was associated with the outbreak. Products from these two plants were distributed to more than 300 retailers in the province, leading to extensive cross-contamination of retail stock. L. monocytogenes is ubiquitous, and contamination can occur subsequent to heat treatment, which usually precedes cheese production. Contaminated soft-textured cheese is particularly prone to bacterial growth. Ongoing regulatory and industry efforts are needed to decrease the presence of Listeria in foods, including pasteurized products. Retailers should be instructed about the risk of cross-contamination, even with soft pasteurized cheese and apply methods to avoid it. Copyright ©, International Association for Food Protection.
Mabit L.,International Atomic Energy Agency |
Benmansour M.,Center National Of Lenergie |
Abril J.M.,University of Seville |
Walling D.E.,University of Exeter |
And 7 more authors.
Earth-Science Reviews | Year: 2014
Increasing anthropogenic pressures coupled with climate change impacts on natural resources have promoted a quest for innovative tracing techniques for understanding soil redistribution processes and assessing the environmental status of soil resources. Among the different existing tracers, the fallout component of the radioisotope lead-210, also termed unsupported or excess lead-210 (210Pbex) when referring to its presence in soil or sediment, arguably offers the broadest potential for environmental applications, due to its origin and relatively long half-life. For more than five decades, 210Pbex has been widely used for dating sediments, to investigate sedimentation processes and, since the 1990s, to provide information on the magnitude of soil and sediment redistribution.The aim of this review is to provide a comprehensive evaluation and discussion of the various applications of 210Pbex as a tracer in terrestrial and aquatic environments, with particular emphasis on catchment sediment budget investigations. This paper summarizes the state-of-the-art related to the use of this tracer, the main assumptions, the requirements (including the need for accurate analytical measurements and for parallel validation), and the limitations which must be recognised when using this fallout radionuclide as a soil and sediment tracer. Lessons learned and current and future research needs in the environmental and radiochronological application of 210Pbex are also presented and discussed. © 2014 Elsevier B.V.
Hache R.,Institute Of Recherche Sur Les Zones Cotieres |
Lanteigne C.,Ministere de lAgriculture |
Hebert Y.,Institute Of Recherche Sur Les Zones Cotieres
Aquaculture | Year: 2016
Live food represents one of the major sources of bacterial contamination in larval culture. Since Artemia are widely used as live food, this approach has been thoroughly studied. Several techniques using antibiotics, ozone, chemical compounds, algae, and probiotics, have been tested to reduce bacterial load in Artemia. This research looked at the potential of salt to reduce bacterial contamination. Two salt treatments, consisting of 1 - a dip in a 200gL-1 salt solution, and 2 - a 24h enrichment in a 60gL-1 salt solution, were compared to a commercial antimicrobial enrichment product (A1 DHA Selco), a mix of commercial antibacterial products and a non-antimicrobial enrichment product (AlgaMac) as well as a control (enriched with AlgaMac). All treatments induced a reduction of the bacterial count of over 99.999983%. It was expected that different enrichment products would induce variations in the nutrient profiles, but the levels of DHA were higher in the Artemia treated with either of the salt treatments, when compared to the control. The salt treatment did not affect EPA and ARA levels, neither did it affect the levels of vitamins C and E. Therefore, salt allows for a comparable or higher reduction of the bacterial load in Artemia nauplii, than that obtained with other techniques, with a limited effect on nutrient profiles. Even more, the use of salt does not limit the choice of the enrichment product used, since it can be used in combination with a non-antibacterial enrichment product. Statement of relevance: Utilization of salt allows for a comparable or higher reduction of the bacterial load in Artemia nauplii than the ones obtained with more complicated or less durable techniques such as antibiotics, formaldehyde and ozone. As demonstrated in the present study, commercial enrichment products exist that allow for an achievement of similar results, but the use of salt does not limit the choice to enrichment products containing antimicrobial compounds, and produces minimal variations in the nutritional profiles of the Artemia. Therefore this new technique could be useful for all fish culture using Artemia. © 2015 Elsevier B.V.