Contamination of Groundwater Systems in the US and Canada by Enteric Pathogens, 1990–2013: A Review and Pooled-Analysis

BackgroundUp to 150 million North Americans currently use a groundwater system as their principal drinking water source. These systems are a potential source of exposure to enteric pathogens, contributing to the burden of waterborne disease. Waterborne disease outbreaks have been associated with US and Canadian groundwater systems over the past two decades. However, to date, this literature has not been reviewed in a comprehensive manner.Methods and principal findingsA combined review and pooled-analysis approach was used to investigate groundwater contamination in Canada and the US from 1990 to 2013; fifty-five studies met eligibility criteria. Four study types were identified. It was found that study location affects study design, sample rate and studied pathogen category. Approximately 15% (316/2210) of samples from Canadian and US groundwater sources were positive for enteric pathogens, with no difference observed based on system type. Knowledge gaps exist, particularly in exposure assessment for attributing disease to groundwater supplies. Furthermore, there is a lack of consistency in risk factor reporting (local hydrogeology, well type, well use, etc). The widespread use of fecal indicator organisms in reported studies does not inform the assessment of human health risks associated with groundwater supplies.ConclusionsThis review illustrates how groundwater study design and location are critical for subsequent data interpretation and use. Knowledge gaps exist related to data on bacterial, viral and protozoan pathogen prevalence in Canadian and US groundwater systems, as well as a need for standardized approaches for reporting study design and results. Fecal indicators are examined as a surrogate for health risk assessments; caution is advised in their widespread use. Study findings may be useful during suspected waterborne outbreaks linked with a groundwater supply to identify the likely etiological agent and potential transport pathway

Are the major antioxidants derived from soy protein and fructo-oligosaccharides model systems colored aqueous soluble or insoluble compounds?

9 páginas, 6 figuras, 1 tabla.The present research aimed to determine the overall antioxidant capacity of solid model glycation systems based on either defatted soy flour or soy protein isolate as protein sources and fructo-oligosaccharides (FOS). In addition, we try to gain insight into the physicochemical characteristic of the major neo-antioxidants generated during heating of the model systems. These compounds may be formed in thermally processed foods containing as ingredients both components soy proteins and FOS. Samples constituted by protein source and FOS alone were employed as controls. The Maillard reaction was induced by heating at 150 °C for 1 h. Formation of colored compounds was detected by measuring the absorbance at 420 nm wavelength. The overall antioxidant capacity of the samples was either directly measured by the QUENCHER (quick, easy, new, cheap and reproducible) approach concept adapted to the ORACFL assay or indirectly by summing the ORAC values obtained by analysis under ORACFL standard conditions of aqueous and ethanol fractions of the samples. The sets of data were compared. The relationship between browning and antioxidant capacity was investigated. All samples excepting unheated FOS showed antioxidant capacity. Data seem to indicate that the QUENCHER approach allowed to determine in a single step, the overall antioxidant capacity of FOS caramels and thermally processed glycation mixtures leading to significant compositional changes as results of the simultaneous occurrence of reactions, such as Maillard, caramelization and thermoxidation. Our results also suggested a major formation of aqueous-soluble colored antioxidants from caramelization and Maillard reactions.This research was funded by the COST Action 927 ‘‘Thermally Processed Foods: possible health implications’’, Ministerio de Ciencia e Innovación (projects AGL2008-2541/ALI, AGL2007- 63462/ALI) and CONSOLIDER INGENIO 2010 program (FUN-CFOOD CSD 2007-063).Peer reviewe