TOXICITY OF FOOD

Author: GUTIERREZ FERNANDEZ ANGEL JOSE.
Year: 2004.
University: LA LAGUNA.
Place of defense: FACULTAD DE MEDICINA DE LA UNIVERSIDAD DE LA LAGUNA.
Place of preparation: FACULTAD DE BIOLOGIA E INSTITUTO DE MEDICINA LEGAL.

Summary: This dissertation deals with the study of heavy metals, toxic as critical of various brands and presentations mussel (Mytilus spp.), Cockles (Cerastoderma adule) zamburiñas (Chlamys varies) and knives (Ensis spp.) Canned on the markets supplies of Santa Cruz de Tenerife and consumer among the island population. This study was performed in order to ascertain the levels of metals in packaged foods, following a critical line on food security. Fundamentally found concentrations of heavy metals and toxic nature of its contribution to the acceptable daily intake or IDA (obtained from the PTWI: provisional tolerable weekly intake) of the same. It also analyzed the heavy metal content of essential character and its contribution to the recommended daily intake (RDA) also established correlations between the concentration of metals, the size of the units, their ash content, etc.. To carry out the analysis of the content of heavy metals, was used to the atomic absorption spectrophotometry with graphite chamber for lead and cadmium, to the atomic absorption spectrophotometry with cold steam generator hydrides for mercury and spectrophotometry of with coupled plasma atomic emission inductivamente for metals chromium, manganese, nickel, iron, zinc and copper. Once the levels of these metals were analyzed statistically with parametric or non - parametric test according to the normality of the data and to establish significant differences between species, brands and presentations.

Author: LAPARRA LLOPIS JOSE MOISES.
Year: 2005.
University: VALENCIA.
Place of defense: INSTITUTO DE AGROQUIMICA Y TECNOLOGIA DE ALIMENTOS.
Place of preparation: FACULTAD DE FARMACIA.

Summary: This work Doctoral thesis focuses on the study of the bioavailability of arsenic and its chemical species in food. Arsenic is metaloide widely distributed in nature, food being the main route of exposure for humans. The toxicity of arsenic depends on its chemical form, hence the importance of speciation in the toxicological risk assessment. Studies of arsenic in food preferably have addressed the characterization of arsenic species in raw products. However, so far no known background on the study of the bioavailability of arsenic and its chemical species in food. To estimate the bioavailability of arsenic have been selected three food groups: Algae for its high arsenic content, fish for its high contribution to the intake of this element and rice as they currently represent the largest source of toxic to most of 50 million people. It has implemented a digestion gastrointestinal simulated to evaluate the bioaccesibilidad (maximum concentration of soluble element), as a prerequisite to its absorption, and has been introduced in a model in vitro cell culture (cells Caco-2, validated model of intestinal epithelium) estimating the retention and transport, in order to make a better approximation to the situation in vivo. The bioaccesibilidad arsenic and its chemical species analyzed in food is high, exceeding 60%, a fact which demonstrates the high solubility in the gastrointestinal available for absorption. The cooked, does not alter the chemical species or decreases bioaccesibilidad. Based on the fraction bioaccesible of food under review, the cellular retention of arsenic is very low (1-6%) is higher transport (4-18%) of the various species. The cell line Caco-2 has not been used to evaluate the biological effects of arsenic level bowel. Since the intestinal epithelium is the first physiological barrier to toxic, studies relating to the integrity of the cell monolayer, mitochondrial activity, oxidative stress and cell cycle progression, allowing start the physiological characterization of the behavior of this cell line after exposure to inorganic arsenic. In these studies demonstrated the production of oxidative stress, the disruption of the integrity of the cell monolayer and the effect of exposure to As (III) in cell cycle progression. The study of the processes of recruitment and transportation of As (III) in the cells Caco-2 shows that there is a system in saturable mediated internalization of cell toxicity in the sense transport apical-basal. The studies carried out in this Doctoral Thesis, can be considered pioneers in the toxicological risk assessment of arsenic and its species from food, to include the bioavailability of the toxic food, as it will be consumed.

Author: SOLER QUILES CARLA MARIA.
Year: 2006.
University: VALENCIA.
Place of defense: FACULTAD DE FARMACIA (UNIVERSIDAD DE VALENCIA).
Place of preparation: FACULTAD DE FARMACIA.

Summary: The objective of this project is to develop analytical methods rapid, specific and sensitive for the control of pesticide residues and their degradation products in food products. This is intended; 1 - Develop methods of extraction multirresiduo that identify a broad range of compounds in fruit and vegetables. 2 - Develop methods of separation, identification and quantification for pesticides widely used in the Community of Valencia, from fruit extracts based on liquid chromatography coupled with mass spectrometry, To achieve these objectives suggested the following scheme of work: 1 - To conduct a literature review for information on the characteristics of the pesticide to be analyzed and analytical methodologies proposed for determining 2 - Develop methods of extraction multirresiduo to identify a large group of compounds with different characteristics present in fruits and vegetables to assessing the quality of the same? To test analytical techniques proposed by optimizing the conditions necessary for the determination of pesticides: * Chromatography líquida-espectrometría mass cuadrupolo simple as using APCI and ESI interfaces mode of ionization positive and negative. * Chromatography líquida-espectrometría Mass in tandem using different cuadrupolos like: Trap or of ions or Triple Cuadrupolo or Cuadrupolo-Tiempo flight? Lastly, the proposed methods are applied to real samples of the Valencia region, in order to assess the population intakes of pesticides studied. METHODOLOGY 1-Pesticides: Pesticides have already been selected on the basis of frequency of use on citrus crops, vineyards, rice and vegetables in general. Among them: Acrinatrin, Buprofezin, Bupirimato, Carbosulfan, Ciproconazol,? -Cihalotrin, Fluvalinate, Hexaflumuron, Kresoxim, Pirifenox, Piriproxifen, Propanil and Tebufenpirad. 2-Techniques of extraction: apply different extraction techniques such as: a) Extraction Sólido-Líquido (ESL): The formal method for the analysis of pesticides in fruit and vegetables in the region of Valencia as the DOGV 134/1995. Examine different organic solvents to make the optimum extraction of all pesticides in the study using smaller quantities of solvent and possible smaller quantities of sample problem. A representative portion of the sample (200 g of the whole fruit) is cut into small pieces and mixed with a food processor Bapitaurus (Taurus, Berlin, Germany). So, it weighs a portion of 0.5 g mixed with 25 g of sodium sulfate anhydrous. For the preparation of the samples fortified, 100 Â µ l of the standard solution was added to 0.5 g sample, at least three hours to begin the extraction process. B) Dispersion of Matrix in Solid Phase (DMFS): Consists of homogenizing the sample with a solid phase, and after placing the mixture in a column, eluir pollutants with mixtures of organic solvents. This technique is one of the most promising for extraction and concentration of organic micropollutants in food because it includes several stages in a single process. A representative portion of the sample (200 g of the whole fruit) is cut into small pieces and mixed with a food processor Bapitaurus (Taurus, Berlin, Germany). So, it weighs a portion of 0.5 grams in a mortar was mixed with 0.5 g C18. For the preparation of the samples fortified, 100 Â µ l of the standard solution was added to 0.5 g sample. The mixture was homogenized write in a column of glass 100 x 9 mm ID Then 10 min 8 l of a 6b7 mixture diclorometano-metanol (80:20 v / v) are eluir through the sample. The eluato is concentrated under nitrogen flow, up 0.5 ml. Finally, 10 Â µ l of the final statement are injected into the system CL. 3-Technical Analysis: The chromatographic separation will be carried out with a column analytical Moon C18 (250 x 4.6 mm ID 5Â µ m) preceded by a pre-C18 (4 x 2 mm ID) both of Phenomenex (Chesire, UK). The mobile phase used is a gradient methanol. The detection is performed by mass spectrometry and will have four teams: -Espectrómetro mass HP 1100 of cuadrupolo simple -Espectrómetro mass Esquire 3000 of Brucker Daltonics trap with the same ion chromatography system that the team earlier. Mass Spectrometer - API 3000 triple cuadrupolo with the same set of chromatography that the team earlier. Spectrometer-mass QSTAR of Cuadrupolo-Tiempo flight with the same set of chromatography that the team earlier.