The initial aim of this work was to evaluate processing conditions for extended shelf life (ESL) milk to have a shelf life at refrigeration temperature of 60 d. Milk was processed on a pilot-scale ultra-high-temperature processing plant and evaluated for microbial and sensory quality over 60 d at 7°C storage. Results of this study showed that lower process temperatures were preferable to minimize cooked flavors and that the minimum safe processing temperature was 134°C for 4 s as determined by the destruction of bacterial spores in the processed milk. Consumer preference panel results indicated that consumers preferred milk processed at 134°C for 4 s (those recommended in this study for ESL processing) to commercial UHT milk although there was a slight preference for pasteurized milk. The critical sensory characteristic of the processed milk was a cooked flavor, which decreased with lower processing temperature and shorter storage time; however, a significant increase in flavors that could be associated with lipolytic activity was also noted. This study highlighted deficiencies in existing methods for determining heat-stable bacterial products in thermal-processed foods. No rapid, sensitive assay for detection of heat-stable spores or lipases in milk exists. If such assays were available, it would allow processors to determine Lipase activity and bacterial spore counts before processing and direct raw milk with low spore counts and low lipolytic activity into long-shelf-life products. To this end, assays to rapidly quantitate spores and lipolytic activity in milk were developed. The lipase assay relies on the hydrolysis of p-nitrophenyl caprylate liberating a yellow color that is detected using reflectance colorimetry. The assay is sensitive to 5 mUnits/ml and is linearly correlated to spectrophotometry (r2 = 0.93) and release of titratable free fatty acids (r2 = 0.92 to 0.97). An immunocapture, enzyme-linked immunoassay coupled with a fluorescent detection system was developed for and resulted in a prototype spore assay using Bacillus stearothermophilus spores. This organism was selected because it is extremely heat resistant, is commonly found in milk, and is associated with spoilage of milk and milk products. The assay was able to quantitate spores down to 103 cfu/ml in milk and other products in about 1.5 h. Other detection limits could be set if needed.

Qu'est-ce qui pousse les citadins à jardiner, dans des contextes souvent peu favorables, les abords de leur logement ? Guidé par cette question, notre travail se focalise sur les pratiques habitantes du jardin privé de type balcon, loggia, terrasse et pied d'immeuble. Parmi les nombreux travaux consacrés à l'étude des modes d'habiter urbains, peu se sont jusque-là spécifiquement intéressés au rôle du "petit" jardin. Comment ce petit jardin – et en particulier son jardinage - permet-il à la fois de se ménager un chez-soi et de cohabiter avec ses voisins ? C'est cette problématique que nous avons explorée en inscrivant notre travail dans le champ des ambiances architecturales et urbaines, c'est-à-dire en faisant de l'environnement sensible une clé de lecture privilégiée des pratiques habitantes jardinières. Notre enquête a porté sur quinze ensembles de logements grenoblois et parisiens situés en milieu urbain dense. Sur une période de quatre ans, elle s'est déployée autour du recueil de la parole habitante, couplée à des observations ethnographiques. Adoptant une approche pluridisciplinaire qui croise les dimensions spatiales, horticoles, sociales et sensibles du jardin, l'analyse s'attache à élaborer une typologie de configurations de jardins à partir de quatre critères : la morphologie (horticole et paysagère) des jardins, leur imaginaire, les perceptions sensibles et les tactiques habitantes dont ils sont le support. Cette typologie propose une rhétorique jardinière explicitant les formes de liens et de ruptures que les habitants créent entre eux et leurs voisins, entre leur logement et leur jardin, entre leur jardin et le voisinage et entre leur jardin et la ville. Elle intéresse directement la programmation et la conception des abords de l'habitat en questionnant les manières de composer le jardin et ses articulations au logement, d'agencer les logements entre eux et de penser le rapport du logement à la ville par le biais du jardin. Deux expériences pédagogiques réalisées à la fin de la recherche rendent compte de ce potentiel. Plus largement, cette recherche ouvre vers l'hypothèse selon laquelle les enjeux de l'habiter urbain se situeraient à la lisière jardinée entre un chez-soi (qu'il soit privé ou public) et la ville. / What encourages city dwellers to garden their housing surroundings often located in unfavourable contexts? Following this question, this research focuses on the residents' practices in private gardens such as balcony, loggia, terrace and ground garden. Among the numerous works about the different types of urban dwellings, few of them interest in the role of small gardens. How do small gardens -and its gardening- allow handling carefully a home and help living together among neighbours? This research question is tackled through the field of urban and architectural ambiences, in which the sensory environment is considered a key element in reading residents' gardening practices. For elaborating this work, we conducted a survey on fifteen dwellings, located in high-density urban context in two different French cities: Grenoble and Paris. During four years, we realised semi-directive interviews in addition to ethnographic observations in sixty households. We analysed the collected data through a pluridisciplinary approach that crosses spatial, horticultural, social and sensory dimensions of gardening. This approach aims at designing a typology -gathering configurations of gardens- based on four criteria: gardens' morphology, its imaginary, sensory perception and residents' tactics. This typology proposes a rhetoric gardening that explores the different links and ruptures that residents create between them and their neighbours, their housing and their garden, their garden and the neighborhood and finally between the garden and the city. This work deals directly with the housing surroundings briefing and design by reappraising how gardens are composed and linked to the housing, how housings are organized with each other, while examining at the same time the way that gardens link together housing projects to the city. Two educational experiences have been realised in two French schools of architecture at the end of this research in order to test the design potentials of our typology. In a wider sense, we theorize that the urban dwelling issues are anchored in a gardening edge between a home (set on a private or public space) and the city.