Search results for "Contamination"

Optimization of PMAxx pretreatment to distinguish between human norovirus with intact and altered capsids in shellfish and sewage samples

2018

Shellfish contamination by human noroviruses (HuNoVs) is a serious health and economic problem. Recently an ISO procedure based on RT-qPCR for the quantitative detection of HuNoVs in shellfish has been issued, but these procedures cannot discriminate between inactivated and potentially infectious viruses. The aim of the present study was to optimize a pretreatment using PMAxx to better discriminate between intact and heat-treated HuNoVs in shellfish and sewage. To this end, the optimal conditions (30 min incubation with 100 μM of PMAxx and 0.5% of Triton, and double photoactivation) were applied to mussels, oysters and cockles artificially inoculated with thermally-inactivated (99 °C for 5 …

Effects of Apirolio Addition and Alfalfa and Compost Treatments on the Natural Microbial Community of a Historically PCB-Contaminated Soil

2018

Abstract Polychlorinated biphenyls (PCBs) are ubiquitous and persistent organic pollutants generated exclusively from human sources and found in the environment as several congeners (e.g. Apirolio, produced in Italy and used for electrical transformers). To evaluate the ability of the natural microbial community of historically PCB-contaminated soil to transform or degrade PCBs after fresh contamination through the addition of Apirolio, a microcosm experiment was conducted in a greenhouse for approximately 8 months. Compost and Medicago sativa (alfalfa) were additionally used in the microcosms to stimulate microbial PCB degradation. Chemical analyses were performed to evaluate PCB concentra…

Human-Driven Microbiological Contamination of Benthic and Hyporheic Sediments of an Intermittent Peri-Urban River Assessed from MST and 16S rRNA Gene…

2017

International audience; Rivers are often challenged by fecal contaminations. The barrier effect of sediments against fecal bacteria was investigated through the use of a microbial source tracking (MST) toolbox, and by Next Generation Sequencing (NGS) of V5-V6 16S rRNA gene (rrs) sequences. Non-metric multi-dimensional scaling analysis of V5-V6 16S rRNA gene sequences differentiated bacteriomes according to their compartment of origin i.e., surface water against benthic and hyporheic sediments. Classification of these reads showed the most prevalent operating taxonomic units (OTU) to be allocated to Flavobacterium and Aquabacterium. Relative numbers of Gaiella, Haliangium, and Thermoleophilu…

What is the risk of acquiring bacteria from prior intensive care unit bed occupants?

2017

Modeling the heat inactivation of foodborne pathogens in milk powder : High relevance of the substrate water activity

2017

International audience; Due to the ability of foodborne pathogens to survive in low moisture foods, the decontamination of these products is an important issue in food hygiene. Up to now, such decontamination has mostly been achieved through empirical methods. The intention of this work is to establish a more rational use of heat treatment cycles. The effects of thermal treatment cycles on the inactivation of dried Salmonella Typhimurium, Salmonella Senftenberg, Cronobacter sakazakii and Escherichia coli were assessed. Bacteria were mixed with whole milk powder and dried down to different water activity levels (0.11, 0.25, 0.44 and 0.58). The rate of inactivated bacteria was determined afte…

Evaluation of Alternaria mycotoxins in strawberries: quantification and storage condition

2016

Alternariol (AOH), alternariol methyl ether (AME) and tentoxin (TEN) are Alternaria mycotoxins produced by the most common post-harvest pathogens of fruits. The production of these metabolites depends on several environmental factors, mainly temperature, water activity, pH and the technological treatments that have been applied to the product. In this study, the occurrence of AOH, AME and TEN was evaluated in strawberries samples stored at different temperatures ranges (at 22 ± 2 or 6 ± 2°C) and different periods (up to 1 month) simulating the current practice of consumer's storage conditions. Sample extraction was performed using a liquid-liquid extraction method prior to LC-MS/MS analysis…

Enteric bacteria of food ice and their survival in alcoholic beverages and soft drinks

2017

This study aimed to evaluate the levels of enteric bacteria in ice cubes produced in different environments (home-made, prepared in bars and pubs with ice machines and produced in industrial plants) and to determine their survival in different alcoholic beverages and soft drinks. Members of the Enterobacteriaceae family were found in almost all samples analysed. All industrial and the majority of home-made samples did not contain coliforms. Enterococci were not identified in domestic samples while they were detected in two industrial and three bar/pub samples. The samples collected from bars and pubs were characterized by the highest levels of enteric bacteria. Fourteen strains representing…

Evaluation of antimicrobial resistance and virulence of enterococci from equipment surfaces, raw materials and traditional cheeses

2016

Forty enterococci isolated along the production chains of three traditional cheeses (PDO Pecorino Siciliano, PDO Vastedda della Valle del Belìce, and Caciocavallo Palermitano) made in Sicily (southern Italy) were studied for the assessment of their antibiotic resistance and virulence by a combined phenotypic/genotypic approach. A total of 31 Enterococcus displayed resistance to at least one or more of the antimicrobials tested. The strains exhibited high percentages of resistance to erythromycin (52.5%), ciprofloxacin (35.0%), quinupristin–dalfopristin (20.0%), tetracycline (17.5%), and high-level streptomycin (5.0%). The presence of tet(M), cat(pC221), and aadE genes for resistance to tetr…

Influence of environmental pollution with creosote oil or its vapors on biomass and selected physiological groups of microorganisms

2017

Survival of microorganisms in soils from treatment facility and landfill of wooden railway sleepers contaminated with creosote oil as well as in two types of soils with different content of organic carbon, treated with creosote oil vapors, was assessed. Microbiological assays including determination of: the biomass of living microorganisms method and the number of proteolytic, lipolytic and amylolytic microorganisms were carried out under laboratory conditions. Chromatography analysis of the soil extract from railway sleepers treatment facility was performed using GC/MS. The highest biomass and the number of tested microorganisms were determined in soils from wooden railway sleepers landfil…

Hepatitis E virus in lettuce and water samples: A method-comparison study

2017

The hepatitis E virus (HEV), which is an increasing cause of acute viral hepatitis in Europe, is a zoonotic virus that is mainly transmitted through contaminated water, consumption of raw or undercooked meat from pigs or wild boar, blood transfusion, and organ transplantation. Although the role of HEV transmission through contaminated produce has not been confirmed, the presence of HEV has been reported in irrigation waters and in vegetables. The present study used a World Health Organization (WHO) international standard and clinical samples to evaluate the performance characteristics of three RT-qPCR assays for detection and quantification of HEV. Two of the evaluated assays provided good …