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Made available in DSpace on 2014-06-11T19:23:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-16Bitstream added on 2014-06-13T18:50:36Z : No. of bitstreams: 1 cattelan_mg_me_sjrp.pdf: 524923 bytes, checksum: 3bce9a87a0c4a61e1bfe2667f3552a2f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / É crescente o número de consumidores que têm exigido da indústria alimentícia a adoção de políticas que visem à segurança de seus produtos. Dentro deste âmbito, a adoção de medidas que reduzam o uso de aditivos químicos torna-se cada vez mais iminente. Verifica-se um crescente interesse em pesquisas pela busca de compostos alternativos para um emprego racional como conservantes de alimentos, dentre os quais pode-se destacar o uso de especiarias, seus óleos e extratos como agentes antimicrobianos. O presente estudo teve por intuito avaliar a atividade antibacteriana in vitro de óleos essenciais de algumas especiarias, em concentrações de 1%, 2% e 5% (v/v), sobre bactérias contaminantes de alimentos. O estudo in situ foi realizado com o óleo essencial que resultou em maior inibição bacteriana in vitro. Fez-se uso amostras comerciais de óleos essenciais de alecrim (Rosmarinus officinalis L.), coentro (Coriandrum sativum L.), cravo (Eugenia caryophyllata Thumb), manjericão (Ocimum basilicum L.), orégano (Origanum vulgare L.), sálvia (Salvia officinalis) e tomilho (Thymus vulgares L.), sobre as seguintes cepas de micro-organismos: Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Salmonella typhimurium (ATCC 14028) e Staphylococcus aureus (ATCC 25923). O estudo da atividade antibacteriana in vitro dos óleos essenciais foi efetuado por meio do procedimento de difusão em meio sólido, por disco e por poço. Os micro-organismos foram inoculados na concentração de 108 UFC.mL-1. Halos de inibição superiores a 10 mm foram considerados significativos de atividade antibacteriana. Para o estudo da atividade antibacteriana in situ optou-se pela utilização do óleo essencial que resultou na maior atividade antimicrobiana... / The study aimed to evaluate the antibacterial activity in vitro of essential oils of some spices in concentrations of 1%, 2% and 5% on foodborne pathogens. Commercial samples of essential oils of rosemary (Rosmarinus officinalis L.), coriander (Coriandrum sativum L.), clove (Eugenia caryophyllata Thumb), basil (Ocimum basilicum L.), oregano (Origanum vulgare L.), sage (Salvia officinalis) and thyme (Thymus vulgares L.) was evaluated against the following strains of microorganisms: Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Salmonella Typhimurium (ATCC 14028) and Staphylococcus aureus (ATCC 25923). Antibacterial activity in vitro of essential oils was carried out by the diffusion method, for disk and well. The microorganisms were inoculated at a concentration of 108 CFU.mL-1. Inhibition halos exceeding 10 mm were considered significant for antibacterial activity. Antibacterial activity in situ was evaluated using the essential oil which resulted in the highest antimicrobial activity in vitro. Regarding the micro-organism to be used, the bacterium E. coli was chosen because it has high incidence rates in food products. Minas Frescal cheeses were produced with the addition of three concentrations of essential oil mentioned and without the addition of oil (control). The cheeses were contaminated with 108 CFU.g-1, at package, and the count of E. coli was evaluated during product storage. Results showed highest bacterial activity for the oregano oil. Essential oils of clove and thyme also presented microbial inhibition. The most resistant microorganism, P. aeruginosa, wasn’t inhibited by any compound. In situ antibacterial activity of oregano... (Complete abstract click electronic access below)

Orientador: Fernando Leite Hoffmann / Banca: Maria Luiza Silva Fazio / Banca: Crispin Humberto Garcia-Cruz / Resumo: É crescente o número de consumidores que têm exigido da indústria alimentícia a adoção de políticas que visem à segurança de seus produtos. Dentro deste âmbito, a adoção de medidas que reduzam o uso de aditivos químicos torna-se cada vez mais iminente. Verifica-se um crescente interesse em pesquisas pela busca de compostos alternativos para um emprego racional como conservantes de alimentos, dentre os quais pode-se destacar o uso de especiarias, seus óleos e extratos como agentes antimicrobianos. O presente estudo teve por intuito avaliar a atividade antibacteriana in vitro de óleos essenciais de algumas especiarias, em concentrações de 1%, 2% e 5% (v/v), sobre bactérias contaminantes de alimentos. O estudo in situ foi realizado com o óleo essencial que resultou em maior inibição bacteriana in vitro. Fez-se uso amostras comerciais de óleos essenciais de alecrim (Rosmarinus officinalis L.), coentro (Coriandrum sativum L.), cravo (Eugenia caryophyllata Thumb), manjericão (Ocimum basilicum L.), orégano (Origanum vulgare L.), sálvia (Salvia officinalis) e tomilho (Thymus vulgares L.), sobre as seguintes cepas de micro-organismos: Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Salmonella typhimurium (ATCC 14028) e Staphylococcus aureus (ATCC 25923). O estudo da atividade antibacteriana in vitro dos óleos essenciais foi efetuado por meio do procedimento de difusão em meio sólido, por disco e por poço. Os micro-organismos foram inoculados na concentração de 108 UFC.mL-1. Halos de inibição superiores a 10 mm foram considerados significativos de atividade antibacteriana. Para o estudo da atividade antibacteriana in situ optou-se pela utilização do óleo essencial que resultou na maior atividade antimicrobiana... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study aimed to evaluate the antibacterial activity in vitro of essential oils of some spices in concentrations of 1%, 2% and 5% on foodborne pathogens. Commercial samples of essential oils of rosemary (Rosmarinus officinalis L.), coriander (Coriandrum sativum L.), clove (Eugenia caryophyllata Thumb), basil (Ocimum basilicum L.), oregano (Origanum vulgare L.), sage (Salvia officinalis) and thyme (Thymus vulgares L.) was evaluated against the following strains of microorganisms: Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC 8739), Pseudomonas aeruginosa (ATCC 9027), Salmonella Typhimurium (ATCC 14028) and Staphylococcus aureus (ATCC 25923). Antibacterial activity in vitro of essential oils was carried out by the diffusion method, for disk and well. The microorganisms were inoculated at a concentration of 108 CFU.mL-1. Inhibition halos exceeding 10 mm were considered significant for antibacterial activity. Antibacterial activity in situ was evaluated using the essential oil which resulted in the highest antimicrobial activity in vitro. Regarding the micro-organism to be used, the bacterium E. coli was chosen because it has high incidence rates in food products. Minas Frescal cheeses were produced with the addition of three concentrations of essential oil mentioned and without the addition of oil (control). The cheeses were contaminated with 108 CFU.g-1, at package, and the count of E. coli was evaluated during product storage. Results showed highest bacterial activity for the oregano oil. Essential oils of clove and thyme also presented microbial inhibition. The most resistant microorganism, P. aeruginosa, wasn't inhibited by any compound. In situ antibacterial activity of oregano... (Complete abstract click electronic access below) / Mestre

L’exposition aux polluants environnementaux a été associée à de nombreux désordres métaboliques, immunitaires et reproductifs ainsi qu’à divers cancers. De plus en plus de travaux, indiquent que le microbiote intestinal, qui joue un rôle majeur dans l’immunité et le métabolisme de l’hôte, interagit avec les xénobiotiques dont les polluants organiques persistants (POPs) et les contaminants néoformés dans les aliments. Cette interaction peut avoir des conséquences toxicologiques importantes via la modification des fonctions du microbiote intestinal mais également via la métabolisation des xénobiotiques, entraînant une potentielle altération de l'homéostasie de l'hôte. Dans le cadre de cette thèse, nous avons démontré, en modèle in vitro, qu’une exposition aigüe du microbiote intestinal humain au benzo[a]pyrène (hydrocarbure aromatique polycyclique) a entraîné une altération des fonctions du microbiote intestinal au niveau du volatolome et du métatranscriptome microbien. Cependant, dans nos conditions expérimentales, aucun impact sur la structure microbienne n'a été observé. L’Homme étant continuellement exposé à un panel de composés chimiques environnementaux, nous avons par la suite étudié l'impact de divers POPs et produits néoformés dans les aliments sur le microbiote intestinal humain. Des familles de gènes ainsi que des composés volatiles microbiens ont été identifiés comme altérés après l’exposition, conduisant à une perturbation de l'activité microbienne. Nous avons finalement démontré que l'interaction microbiote-polluant pourrait conduire à l'établissement d'un état pro-inflammatoire modéré dans l'intestin avec une libération de cytokine IL-8 par les cellules épithéliales intestinales. Ces résultats appuient le concept émergent selon lequel les contaminants alimentaires pourraient altérer les activités du microbiote intestinal. / Exposure to environmental pollutants has been associated with various life-threatening disorders, including dysregulation of the immune and reproductive systems, metabolic diseases and various cancers. Growing evidences indicate that the gut microbiota, which plays major roles in host metabolic and immune functions, interacts with xenobiotics including persistent organic pollutants (POPs) and foodborne chemicals. The toxicological relevance of the gut microbiota-pollutant interplay is of great concern for the host since the chemicals may disrupt the gut microbiota functions leading to a potential impairment of the host homeostasis. During this PhD thesis, we demonstrated that in vitro acute exposure of the human gut microbiota with benzo[a]pyrene (polycyclic aromatic hydrocarbon) led to an impairment of the gut microbiota functions with a specific shift of the microbial volatolome and metatranscriptome. However, in our experimental conditions, no impact on the microbial structure was observed. Since humans are exposed to a wide range of environmental chemicals we investigated the impact of various POPs and foodborne chemicals on the human gut microbiota. We identified microbial volatiles and gene families that shifted after this exposure leading to an imbalance of the microbial activity. Furthermore, we demonstrated that the interaction between the pollutants and the gut microbiota lead to a significant release of pro-inflammatory IL-8 cytokine by the intestinal epithelial cells which may contribute to the establishment of a low-grade inflammatory state in the gut. All together, these data support the emerging concept that food pollutants could alter the gut microbiota activities.

Le travail de thèse décrit dans ce manuscrit porte sur l’étude de la présence de biocides désinfectants dans les produits laitiers et sur l’impact des procédés de transformation du lait sur l’apparition de produits néoformés. Les biocides désinfectants sont des composés chimiques utilisés quotidiennement en industrie laitière lors des procédures de nettoyage-désinfection (ND) des surfaces en contact avec les aliments. Les ammoniums quaternaires de type chlorure de Benzalkonium (BACs) et chlorure de dialkyldimethylammonium (DDACs), et l’Aminopropyldodécylpropane diamine sont les désinfectants les plus largement utilisés en industrie laitière. Ces biocides peuvent entrainer des résidus sur les surfaces alimentaires, ce qui présente un risque pour la santé du consommateur. Dans le but de mesurer l’exposition des consommateurs, deux méthodes analytiques fiables ont été développées pour l'analyse de ces substances dans les produits laitiers impliquant la chromatographie liquide couplée à la spectrométrie de masse en tandem. Le lait cru de vache, la poudre de lait entier, les fromages à pâte pressée cuite et les fromages fondus ont été sélectionnés pour représenter la diversité des produits laitiers. L'évaluation des performances de chacune des méthodes a été réalisée par une approche globale basée sur le profil d'exactitude. Pour la plupart des composés et des matrices étudiés, les méthodes d'analyse ont été validées sur l’intervalle de dosage de 5 à 150 μg / kg. Pour répondre au questionnement de l'impact des procédés de transformation du lait sur les résidus de biocides désinfectants, l'évolution des teneurs en composés et leur devenir dans les différentes matrices issues du lait ont été étudiées. Pour cela, deux études de faisabilité mettant en oeuvre des comparaisons d'empreintes chimiques globales, acquises par spectrométrie de masse à haute résolution, de fromages fondus et de fromages à pâte dure (contaminés vs témoins) ont été réalisées. Ces études ont permis de détecter 4 ions discriminants liés à la présence de biocides dans le fromage fondu. Leur identification reste à réaliser. Tout ce travail a été réalisé à des fins de sécurité alimentaire. La première partie est à l'élaboration de méthodes analytiques ciblées pour les résidus de biocides dans le lait et les produits laitiers permettant ainsi de mesurer les résidus de biocides sur les denrées alimentaires. Ces mesures sont nécessaires pour effectuer une analyse du risque liée à ces résidus. La deuxième partie est en relation avec la question du comportement des résidus de biocides lors de la transformation du lait présentant la stratégie, les résultats que nous pourrions obtenir et la perspective de travaux futurs. / The thesis work focuses on the presence of disinfectants biocides in dairy products and on the impact of milk processing on the possible appearance of process-induced food contaminants related to the exposition of milk with biocides. Disinfectants biocides are chemicals daily used in the dairy industry in cleaning-disinfection (CD) processes of food contact surfaces. Quaternary ammoniums as benzalkonium chloride (BACs) and dialkyldimethylammonium chloride (DDACs), and the Aminopropyldodecylpropane diamine are the most widely used disinfectants in dairy industry. These biocides can lead residues on the surfaces of food contact materials therefore present a health risk for the consumer. With aim of measuring consumers exposure, two reliable analytical methods have been developed for the analysis of these substances in dairy products involving liquid chromatography hyphenated with tandem mass spectrometry. Raw cow's milk, whole milk powder, hard pressed and processed cheeses were selected as representing the diversity of dairy products. The evaluation of the performances of each of the methods was carried out by the global approach based on the accuracy profile. For most of compounds and matrices studied, analytical methods were validated within the range of 5 to 150 μg/kg. To answer to the questioning of the impact of milk processes on biocides disinfectants residues, the evolution of compounds contents and their fate in the various matrices resulting from the milk were studied. For this, two proof-of-concept studies implementing global chemical fingerprint comparisons, acquired by High Resolution Mass Spectrometry, of processed cheese and hard pressed cheese (contaminated vs control) samples were carried out. These studies allowed to detect 4 discriminant ions linked to the presence of biocides in processed cheese. Their identification remains to be done. Whole this work is related for food safety purposes. The first part was linked to elaborate targeted analytical methods for biocides residues in milk and milk products thus allowing the measurement of biocides residues on food. These measurements are necessary for the risk analysis linked to these residues. The second part is in relation with the question of the behavior of biocides residues within milk processing presenting the strategy, the results we could obtain and the perspective for future works.

Introduction: Prenatal exposure to polycyclic aromatic hydrocarbons (PAH) and to acrylamide has been suggested to reduce fetal growth. The role of diet, the main source of exposure to these compounds in the general population, remains uncertain. This thesis aimed to characterize women’s exposure during pregnancy to dietary acrylamide and the genotoxic PAH benzo(a)pyrene [B(a)P], and to assess the effects of prenatal exposure to these compounds on fetal growth indicators. Methods: This thesis was done within two large European population-based cohort studies conducted in Spain and Norway: the INfancia y Medio Ambiente (INMA; n=657) and The Norwegian Mother and Child Cohort (MoBa; n=50651). Dietary B(a)P and acrylamide intakes were estimated based on information from food frequency questionnaires and the concentrations of these compounds in foods. Results: (i) Smokers had higher dietary intakes of B(a)P and acrylamide compared to non-smokers; (ii) the main predictors of B(a)P intake were shellfish and processed/cured meats while the main predictors of acrylamide intake were snacks, fried potatoes, and crisp bread; (iii) higher prenatal exposure to dietary B(a)P and acrylamide may reduce birth weight and increase the risk of small for gestational age, independently of smoking-related exposure and (iv) stronger effects of dietary B(a)P on fetal growth were observed among women with low vitamin C intake. Conclusions: Dietary B(a)P and acrylamide intakes during pregnancy may impair fetal growth. Therefore, reducing the intake of these compounds from the diet should be recommended in dietary guidelines for pregnant women. Likewise, increasing intakes of fruits and vegetables rich in vitamin C should be recommended given its potential to prevent adverse effects from exposure to such contaminants. / Introducción: La exposición prenatal a los hidrocarburos aromáticos policíclicos (HAP) y a la acrilamida ha sido asociada con la reducción del crecimiento fetal. El papel de la dieta, la principal fuente de exposición a estos compuestos en la población general, sigue siendo incierto. Los objetivos de esta tesis son caracterizar la exposición a través de la dieta a la acrilamida y a los HAP, específicamente el compuesto genotóxico benzo(a)pireno [B(a)P], durante el embarazo, y evaluar los efectos de la exposición prenatal a estos compuestos sobre indicadores del crecimiento fetal. Métodos: Esta tesis se realizó dentro del marco de dos grandes estudios europeos de cohortes de base poblacional realizados en España y Noruega: INfancia y Medio Ambiente (INMA; n=657) y The Norwegian Mother and Child Cohort (MoBa; n=50651). La ingesta de B(a)P y acrilamida fue estimada a partir de información de cuestionarios de frecuencia alimentaria y las concentraciones de estos compuestos en los alimentos. Resultados: (i) Las fumadoras tuvieron mayor ingesta de B(a)P y acrilamida a través de la dieta en comparación con las no fumadoras; (ii) los principales predictores de la ingesta de B(a)P fueron los mariscos y los embutidos, mientras que los principales predictores de la ingesta de acrilamida fueron los aperitivos, las patatas fritas y el pan crujiente; (iii) la exposición prenatal al B(a)P y la acrilamida pueden reducir el peso al nacer y aumentar el riesgo de pequeño para la edad gestacional, independientemente de la exposición relacionada con el tabaco y (iv) los efectos de la ingesta de B(a)P a través de la dieta sobre el crecimiento fetal fueron más fuertes entre las mujeres con baja ingesta de vitamina C. Conclusiones: La ingesta de B(a)P y acrilamida a través de la dieta durante el embarazo, puede perjudicar el crecimiento fetal. Consecuentemente, recomendaciones para la reducción de la ingesta de estos compuestos a través de la dieta deberían ser incluidas en las guías dietéticas para mujeres embarazadas. Asimismo, debería recomendarse un aumento en la ingesta de frutas y verduras con alto contenido en vitamina C por su potencial para prevenir efectos relacionados con la exposición a estos contaminantes.

One of the most relevant group of toxicologically significant compounds in beer are N-nitrosamines. In this thesis, the attention was paid especially on non-volatile nitroso compounds whose concentrations in beer, a chemical structure, and a biological effect has not been known yet. For the reason of the lack of knowledge regarding this compound group, the method for their sensitive detection by chemiluminescence detection after gas chromatographic separation was developed. This method permits a classification of detected nitroso compounds to different groups (N-nitroso, C-nitroso, and combination of C-nitroso and nitro) and distinguish them from interferences. The method is based on recording of a pyrolytic profile of each chromatographic peak, the profiles are then processed by discriminant analysis. The method has been developed for finding and structural identification purposes of these unknown compounds. Its application on an artificially nitrosated beer sample, together with gas chromatographic tandem mass spectrometric analysis, led to structural identification of several representatives of nitroso compounds. Sensory active compounds in this thesis are represented by carbonyl compounds and fatty acids. Carbonyl compounds - furfural and hydroxymethylfurfural - were used during the development...