Listeriosis has the highest fatality and hospitalization rate among foodborne illnesses. Listeria monocytogenes causes listeriosis and is a difficult bacterium for ready-to-eat food processors to eliminate because of its ability to grow in the absence of oxygen and under refrigeration. Recently, milk and its proteins have gained recognition as the largest source of biologically active peptides, and, it stands reason that several antimicrobial peptides (AMP) can be released from casein as it is the most abundant milk protein. AMPs are commonly obtained by cutting the whole protein into peptide fragments using enzymes or by acidification. The objective of this study was to predict potential AMPs through computer aided tools, improve hydrolysate preparation, and determine trypsin and pepsin-casein hydrolysate antimicrobial activity in growth media and on frankfurters against two strains of Listeria monocytogenes (Scott A and 310) and Escherichia coli O157:H7 (Salami strain). The prediction study procedure was to identify the most common variants of primary peptide sequences. The sequences were analyzed for greatest possible enzyme cuts on the protein, peptide masses, isoelectric point, net charge and percent hydrophilic residues using online proteomics programs. The fragments were explored for AMP commonalities: fragment length of 3 to 50 amino acids, positive (cationic) net charge, and hydrophilic residues between 25 and 50%. This technique identified 16 potential AMPs which proved that it is possible to screen for AMPs. The method used to determine the trypsin-casein hydrolysate (TCH) and pepsin-casein hydrolysate (PCH) antimicrobial activity was to hydrolyze sodium caseinate with pepsin or trypsin. L. monocytogenes (strains Scott A and 310) were incubated in 0, 10, 20, and 40% PCH and 0 and 50% TCH concentrations over a 24 hour period. PCH suppressed growth of L. monocytogenes Scott A by 1.76 log CFU/mL and reduced initial populations of L. monocytogenes 310 and E. coli O157:H7 by 0.52 and 0.62 log CFU/ml, respectively. TCH had little or no effect on growth suppression of any of the three test organisms. The frankfurter study was conducted by spot inoculating frankfurters with L. monocytogenes Scott A and then dipping frankfurters into one of five treatments (deionized water, pH 2.7 buffer, pH 5.1 buffer, pH 2.7 PCH, and pH 5.1 PCH) for 30 seconds; inoculated frankfurters that were not dipped served as controls. Frankfurters were incubated at 32°C for seven days. The results showed that there was no significant difference (p>0.05) in antimicrobial effectiveness among the treatments and control. This study demonstrated that enzymatically derived casein hydrolysates somewhat inhibit growth of L. monocytogenes and E. coli O157:H7 in culture media, but were ineffective when applied to frankfurters. Casein hydrolysate solutions can be easily made in a processing facility for application in fluid systems such as an antimicrobial spray on beef carcasses and in milk, juice, sports drinks, soda, soups, and yogurt. It also could be used in solid systems such as frankfurters, cheese, ground beef, and processed or RTE foods.

Background: Listeria monocytogenes and ready-to-eat meats have garnered considerable attention in Canada over the past decade as a result of foodborne outbreaks and product recalls that continue to transpire. A number of factors suggest that ready-to-eat meats and Listeria monocytogenes are a wicked problem. They include (among others) the number of stakeholders involved in the processing, distribution and inspection of ready-to-eat meats in Ontario, the ubiquitous and hardy nature of the organism and the challenges associated with eliminating it from ready-to-eat meat products and processing environments. Since Ontario public health units play an integral part in the inspection of ready-to-eat meats in the province, it is important to determine their current role in the wicked problem in order to identify possible solutions for change. Purpose: The purposes of the study were: (1) to determine how Ontario public health units address the wicked problem of Listeria monocytogenes and ready-to-eat meats in their food safety inspection programs using the provincial regulatory framework in addition to the use of research, knowledge translation and innovation; and (2) to develop a theory that identifies gaps (if any) in public health unit inspection practices, provincial legislation or food safety research that serves to generate recommendations to reduce incidence of listeriosis resulting from consumption of RTE meat products. Methodology: The research design used the principles of grounded theory to lead the interview and survey methodology and subsequent data analyses. The study was completed in three phases. Interviews were conducted in the first 2 phases of the study while a survey was conducted in the last phase. Interviews were conducted with public health unit ‘food safety leads’ that met pre-determined eligibility criteria. Following methods used in previous studies,interview data were analyzed in 4 stages of theory development using a grounded theory approach. Through substantive coding and constant comparative methods, core categories were identified in each of the study phases. As a result, theoretical saturation was reached leading to the process of theoretical coding and the emergence of the study theory. Results: In total, 27 public health units of 36 participated in the study. Eleven public health units participated in the first 2 phases of the interviews while 25 public health units (for a total of 45 participants) participated in the survey. The study core category, 'reactive and regulatory practice' evolved from the results of the interviews and survey. As a result, it was determined that: (1) the Ontario provincial regulatory framework including the Food Premises Regulation is almost exclusively responsible for directing food safety inspection practices in food premises; (2) food safety inspection and investigation activities associated with listeriosis outbreaks are the focus of Listeria monocytogenes and ready-to-eat meat research; and (3) innovation and knowledge translation are not currently influenced by inspection practice as a result of the food safety framework which does not require or encourage it. Using the processes of theoretical integration and theoretical coding, the following theory emerged from the data analyses; Ontario public health units manage ready-to-eat meats and Listeria monocytogenes through general population and reactive regulatory processes that focus on local-level, end-product, hazard reduction strategies for established risks in inspected food premises. Strengths and Limitations: The study had several strengths including being the first of its kind to associate ready-to-eat meats and Listeria monocytogenes as a part of a wicked problem. It was also the first study to use grounded theory to illuminate the function and role of Ontario public health units in managing Listeria monocytogenes and ready-to-eat meats. There are a number of limitations to the study including the study sample size, participant inclusion process through provincial public health unit senior management, the generalizability of study results, and method of interviews conducted with participants. Implications: The results of the study have implications for public health researchers and policy/regulatory makers in the province of Ontario. It stresses improved management of Listeria monocytogenes and ready-to-eat meats in food premises using a proactive approach. Conclusions: Using a grounded theory approach, this study demonstrated that Ontario public health units manage ready-to-eat meats and Listeria monocytogenes through reactive and regulatory food safety inspection practices. Survey and interview results indicate that study participants aspire for evidence-based regulatory and program amendments that will allow for proactive and targeted microbial risk-reduction activities at the local level that focus on vulnerable populations. The study substantiates that amendments to the Ontario Food Safety program and in particular, the Food Premises Regulation are necessary.

Background: Listeria monocytogenes and ready-to-eat meats have garnered considerable attention in Canada over the past decade as a result of foodborne outbreaks and product recalls that continue to transpire. A number of factors suggest that ready-to-eat meats and Listeria monocytogenes are a wicked problem. They include (among others) the number of stakeholders involved in the processing, distribution and inspection of ready-to-eat meats in Ontario, the ubiquitous and hardy nature of the organism and the challenges associated with eliminating it from ready-to-eat meat products and processing environments. Since Ontario public health units play an integral part in the inspection of ready-to-eat meats in the province, it is important to determine their current role in the wicked problem in order to identify possible solutions for change. Purpose: The purposes of the study were: (1) to determine how Ontario public health units address the wicked problem of Listeria monocytogenes and ready-to-eat meats in their food safety inspection programs using the provincial regulatory framework in addition to the use of research, knowledge translation and innovation; and (2) to develop a theory that identifies gaps (if any) in public health unit inspection practices, provincial legislation or food safety research that serves to generate recommendations to reduce incidence of listeriosis resulting from consumption of RTE meat products. Methodology: The research design used the principles of grounded theory to lead the interview and survey methodology and subsequent data analyses. The study was completed in three phases. Interviews were conducted in the first 2 phases of the study while a survey was conducted in the last phase. Interviews were conducted with public health unit ‘food safety leads’ that met pre-determined eligibility criteria. Following methods used in previous studies,interview data were analyzed in 4 stages of theory development using a grounded theory approach. Through substantive coding and constant comparative methods, core categories were identified in each of the study phases. As a result, theoretical saturation was reached leading to the process of theoretical coding and the emergence of the study theory. Results: In total, 27 public health units of 36 participated in the study. Eleven public health units participated in the first 2 phases of the interviews while 25 public health units (for a total of 45 participants) participated in the survey. The study core category, 'reactive and regulatory practice' evolved from the results of the interviews and survey. As a result, it was determined that: (1) the Ontario provincial regulatory framework including the Food Premises Regulation is almost exclusively responsible for directing food safety inspection practices in food premises; (2) food safety inspection and investigation activities associated with listeriosis outbreaks are the focus of Listeria monocytogenes and ready-to-eat meat research; and (3) innovation and knowledge translation are not currently influenced by inspection practice as a result of the food safety framework which does not require or encourage it. Using the processes of theoretical integration and theoretical coding, the following theory emerged from the data analyses; Ontario public health units manage ready-to-eat meats and Listeria monocytogenes through general population and reactive regulatory processes that focus on local-level, end-product, hazard reduction strategies for established risks in inspected food premises. Strengths and Limitations: The study had several strengths including being the first of its kind to associate ready-to-eat meats and Listeria monocytogenes as a part of a wicked problem. It was also the first study to use grounded theory to illuminate the function and role of Ontario public health units in managing Listeria monocytogenes and ready-to-eat meats. There are a number of limitations to the study including the study sample size, participant inclusion process through provincial public health unit senior management, the generalizability of study results, and method of interviews conducted with participants. Implications: The results of the study have implications for public health researchers and policy/regulatory makers in the province of Ontario. It stresses improved management of Listeria monocytogenes and ready-to-eat meats in food premises using a proactive approach. Conclusions: Using a grounded theory approach, this study demonstrated that Ontario public health units manage ready-to-eat meats and Listeria monocytogenes through reactive and regulatory food safety inspection practices. Survey and interview results indicate that study participants aspire for evidence-based regulatory and program amendments that will allow for proactive and targeted microbial risk-reduction activities at the local level that focus on vulnerable populations. The study substantiates that amendments to the Ontario Food Safety program and in particular, the Food Premises Regulation are necessary.

The purpose of this study was to analyze and determine the predictive power of individual and a combination of different indicators that are used to determine college readiness. For this study a logistic regression analysis was conducted due to the dichotomous nature of the dependent variable. The dependent variable for the study was the earning of a post-secondary credential. The independent variables included high school diploma type, Advanced Placement course taken, Advanced Placement test performance, SAT performance, ACT performance, a multidimensional index made up of all the variables, and high school GPA. The study found that high school GPA had the strongest odds ratio, Exp(B), for the participants earning a post-secondary credential (Exp(B) = 6.597), followed by diploma type (Exp(B) = 6.316), taking an Advanced Placement course (Exp(B) = 4.368), earning at least one qualifying Advanced Placement test score (Exp(B) = 3.846), a multidimensional index (Exp(B) = 2.318), ACT score (Exp(B) = 1.161) and SAT score (Exp(B) = 1.003). Future analysis is needed by using live data of student's college performance, stratifying the data to account for differences in post-secondary performance by different racial and socio-economic groups, and studying the effects of the State of Texas' chosen college readiness variables.

Thesis (M. Ed.), Memorial University of Newfoundland, 1999. / Bibliography: p. 62-67.

abstract: This research is motivated by a deterministic scheduling problem that is fairly common in manufacturing environments, where there are certain processes that call for a machine working on multiple jobs at the same time. An example of such an environment is wafer fabrication in the semiconductor industry where some stages can be modeled as batch processes. There has been significant work done in the past in the field of a single stage of parallel machines which process jobs in batches. The primary motivation behind this research is to extend the research done in this area to a two-stage flow-shop where jobs arrive with unequal ready times and belong to incompatible job families with the goal of minimizing total weighted tardiness. As a first step to propose solutions, a mixed integer mathematical model is developed which tackles the problem at hand. The problem is NP-hard and thus the developed mathematical program can only solve problem instances of smaller sizes in a reasonable amount of time. The next step is to build heuristics which can provide feasible solutions in polynomial time for larger problem instances. The basic nature of the heuristics proposed is time window decomposition, where jobs within a moving time frame are considered for batching each time a machine becomes available on either stage. The Apparent Tardiness Cost (ATC) rule is used to build batches, and is modified to calculate ATC indices on a batch as well as a job level. An improvisation to the above heuristic is proposed, where the heuristic is run iteratively, each time assigning start times of jobs on the second stage as due dates for the jobs on the first stage. The underlying logic behind the iterative approach is to improve the way due dates are estimated for the first stage based on assigned due dates for jobs in the second stage. An important study carried out as part of this research is to analyze the bottleneck stage in terms of its location and how it affects the performance measure. Extensive experimentation is carried out to test how the quality of the solution varies when input parameters are varied between high and low values. / Dissertation/Thesis / M.S. Industrial Engineering 2012

Dans cette thèse, j'étudie l'émergence, la diffusion, et la transformation du prêt-à-porter à New York et à Paris depuis les années 40 jusqu'aux années 70, au travers de 3 articles constitutifs. L'étude comparative de l'article 1 révèle l'origine, le sens et la complexité du prêt-à-porter en tant qu'innovation. Puis, dans l'article 2, je m'intéresse au processus de diffusion complexe et d'institutionnalisation du prêt-à-porter dans le système de la haute couture, en me concentrant sur le contexte institutionnel, les acteurs clés et les forces influentes. Enfin, dans l'article 3, je décompose le processus de diffusion complexe en quatre étapes et j'examine les différents acteurs et réseaux dans chaque étape, en établissant les interactions entre réseaux et institutions. Dans leur ensemble, ces trois articles enrichissent notre compréhension de la diffusion complexe, y compris ses sens, ses processus sous jacents et mécanismes, depuis des points de vue différents. L'article 1 se concentre sur la complexité du prêt-à-porter lui-même. L'article 2 souligne la complexité depuis le cadre institutionnel et l'adaptation associée au processus de diffusion. L'article 3 traite de la complexité depuis l'évolution des réseaux et leur interaction avec les institutions. / In this dissertation, I study the emergence, diffusion, and transformation of ready-to-wear fashion in New York and Paris from the 1940s to the 1970s through three component papers. The comparative study in paper 1 reveals the origin, meaning, and complexity of ready-to-wear as a business innovation. Then in paper 2, I look into the complex diffusion and institutionalization process of ready-to-wear fashion in the haute couture system, focusing on the institutional context, key actors, and driving forces. Finally, in paper 3, I decompose the complex diffusion process into four stages and examine multiple actors and networks in each stage, addressing the interplay between networks and institutions. Taken together, these three papers enrich our understanding of complex diffusion, including its meanings and the underlying processes and mechanisms, from different angles. Paper 1 focuses on the complexity of ready-to-wear fashion itself. Paper 2 underlines the complexity from the institutional setting and the adaptation associated in the diffusion process. Paper 3 addresses the complexity from the evolution of networks and their interplay with institutions.

A crescente utilização do concreto, que é o produto mais fabricado no mundo em termos de volume, somada à pressão do mercado por redução de custos com manutenção das exigências mínimas para segurança do projeto, tem impacto direto na importância e necessidade do controle de qualidade do material. Para concretos usinados, predominantes em grandes centros urbanos, as normas do país preconizam a não utilização dos 15% iniciais e finais do volume total de concreto do caminhão betoneira para fins de ensaio. No entanto, devido a maior facilidade e agilidade, é constatada como prática comum nos canteiros de obra da região a coleta de amostras logo da primeira porção de concreto descarregado. Considerando tal procedimento, fora do padrão preconizado por norma, somado à ausência de normatização para aferição da qualidade do misturador e uniformidade da mistura do concreto e a importância dos ensaios de controle de qualidade dos concretos perante a segurança das estruturas, a presente pesquisa tem como objetivo analisar as variações de resistência à compressão e de propriedades físicas do concreto ao longo da descarga da mistura em caminhão betoneira. A fim de atingir a meta proposta, realizaram-se coletas de amostras em cinco pontos distintos, ao longo da descarga do concreto do caminhão betoneira, para cada um dos 65 lotes (amassadas) avaliados, considerando três diferentes traços de concreto. Para cada ponto de coleta foram avaliados a resistência à compressão, o abatimento de tronco de cone e o teor de agregado graúdo. Estatisticamente, foi constatado que há amassadas em que a variação do ponto de coleta influencia na resistência à compressão, no entanto não se pode afirmar o mesmo considerando critérios da ABECE, adotados como parâmetro de análise na falta de normatização específica para o tema. Não houve a formação de um perfil representativo das variações de resistência conforme o ponto de coleta, diferentemente do teor de agregado graúdo, em que se pode visualizar claramente um perfil em que há concentração de brita nos pontos extremos, início e final da coleta. Em relação à consistência, de modo geral, houve uma redução do ponto inicial ao final, dentro dos limites de indicados por norma. / The crescent utilization of concrete which in terms of volume, is the most produced product in the world, added to the pressure of the market to reduce the costs and maintenance of the safety minimum requirements of a project, make a direct impact on the material quality control’s importance and necessity. For ready-mixed concrete, mostly seen in large urban centers, the initial and final 15% usage of its total volume is not recommended by the country standards for test purposes. However, due to the ease, it is a common practice in construction sites of the region to collect samples once the first portion of the concrete is unloaded. Taking into account such procedure, which does not meet the standards recommended, added to the lack of standardization to assess the quality of the concrete mixer, the uniformity of the concrete mixture and the importance of the quality control tests of concrete under the safety of structures, the purpose of this research is to analyze the variations of the concrete strength when compressed and its physical properties along the discharge of the mixture made in a mixer truck. In order to achieve the proposed goal, there were sampling carried out at five different points along the discharge from the concrete mixer truck, for each of the 65 lots (batches) analyzed, considering three different types of concrete. Each sampling collected was analyzed by going through a slump test, compression strength and granulometry analysis. Statistically, it was proven that the sample point collection variation of some of the batches influences the compression strength, on the other hand the same cannot be found considering the ABECE criteria, used as analysis parameter in the absence of specific regulations for the subject. No representative profile of resistance variations based on the sample collection point was formed, in contrast to the coarse aggregate content, in which profile can be clearly seen a concentration of gravels at the extreme points, at the commencement and the end of the sample collection. Regarding its consistency, on the whole, there was a reduction from the initial and to the end point, respecting the regulations standards.

Master of Science / Food Science Institute / Elizabeth Boyle / Consumer demand for clean-label and 'all natural' food products has created the need to investigate antimicrobials derived from natural sources. Multifunctional ingredients are food additives that have multiple properties to reduce fat, limit salt, retard oxidation, increase water-holding capacity and inhibit bacterial growth in foods. Multifunctional ingredients that exhibit antimicrobial effects in meat and poultry products can facilitate consumers demand for clean and 'all natural' labels while reducing foodborne illness risk. Previous scientific research has shown that plant essential oils are known to contain active components to prevent oxidation in meat products, but emerging data have shown that these plant-based ingredients also contain antimicrobial properties. Plant essential oils such as basil oil has shown limited Salmonella Enteritidis inhibition in meat model systems and thyme oil has shown Listeria monocytogenes inhibition in low fat beef hotdogs. Intrinsic and extrinsic parameters of meat systems can alter the antimicrobial efficacy of plant essential oils. Although antimicrobial effects were observed with plant essential oils, effective usage levels may be limited to sensory characteristics in certain meat and poultry products. Natural extracts have shown potential antimicrobial properties in meat and poultry applications. Rosemary extract has been shown to suppress the growth of Enterobacteriaceae, Pseudomonas, and yeast and molds in fresh sausage. Grapefruit seed extract has shown inhibition against Campylobacter jejuni in poultry skin and meat models and E. coli O157:H7 in moisture enhanced beef homogenate models. The addition green tea extract in ground beef has been shown to reduce D-values while cooking and inhibit outgrowth of C. perfringens spores during extended chilling of cooked ground beef. Grape seed extract has been shown to reduce Listeria monocytogenes, E. coli O157:H7 and Salmonella Typhimurium populations in cooked lean ground beef stored for 9 days at 4°C. Scientific research findings for plant essential oils and extracts confirm that multifunctional ingredients are relevant to meat and poultry products as potential food additives to control undesirable pathogen and spoilage bacteria while meeting consumer demand for natural, clean-label ingredients.

A crescente utilização do concreto, que é o produto mais fabricado no mundo em termos de volume, somada à pressão do mercado por redução de custos com manutenção das exigências mínimas para segurança do projeto, tem impacto direto na importância e necessidade do controle de qualidade do material. Para concretos usinados, predominantes em grandes centros urbanos, as normas do país preconizam a não utilização dos 15% iniciais e finais do volume total de concreto do caminhão betoneira para fins de ensaio. No entanto, devido a maior facilidade e agilidade, é constatada como prática comum nos canteiros de obra da região a coleta de amostras logo da primeira porção de concreto descarregado. Considerando tal procedimento, fora do padrão preconizado por norma, somado à ausência de normatização para aferição da qualidade do misturador e uniformidade da mistura do concreto e a importância dos ensaios de controle de qualidade dos concretos perante a segurança das estruturas, a presente pesquisa tem como objetivo analisar as variações de resistência à compressão e de propriedades físicas do concreto ao longo da descarga da mistura em caminhão betoneira. A fim de atingir a meta proposta, realizaram-se coletas de amostras em cinco pontos distintos, ao longo da descarga do concreto do caminhão betoneira, para cada um dos 65 lotes (amassadas) avaliados, considerando três diferentes traços de concreto. Para cada ponto de coleta foram avaliados a resistência à compressão, o abatimento de tronco de cone e o teor de agregado graúdo. Estatisticamente, foi constatado que há amassadas em que a variação do ponto de coleta influencia na resistência à compressão, no entanto não se pode afirmar o mesmo considerando critérios da ABECE, adotados como parâmetro de análise na falta de normatização específica para o tema. Não houve a formação de um perfil representativo das variações de resistência conforme o ponto de coleta, diferentemente do teor de agregado graúdo, em que se pode visualizar claramente um perfil em que há concentração de brita nos pontos extremos, início e final da coleta. Em relação à consistência, de modo geral, houve uma redução do ponto inicial ao final, dentro dos limites de indicados por norma. / The crescent utilization of concrete which in terms of volume, is the most produced product in the world, added to the pressure of the market to reduce the costs and maintenance of the safety minimum requirements of a project, make a direct impact on the material quality control’s importance and necessity. For ready-mixed concrete, mostly seen in large urban centers, the initial and final 15% usage of its total volume is not recommended by the country standards for test purposes. However, due to the ease, it is a common practice in construction sites of the region to collect samples once the first portion of the concrete is unloaded. Taking into account such procedure, which does not meet the standards recommended, added to the lack of standardization to assess the quality of the concrete mixer, the uniformity of the concrete mixture and the importance of the quality control tests of concrete under the safety of structures, the purpose of this research is to analyze the variations of the concrete strength when compressed and its physical properties along the discharge of the mixture made in a mixer truck. In order to achieve the proposed goal, there were sampling carried out at five different points along the discharge from the concrete mixer truck, for each of the 65 lots (batches) analyzed, considering three different types of concrete. Each sampling collected was analyzed by going through a slump test, compression strength and granulometry analysis. Statistically, it was proven that the sample point collection variation of some of the batches influences the compression strength, on the other hand the same cannot be found considering the ABECE criteria, used as analysis parameter in the absence of specific regulations for the subject. No representative profile of resistance variations based on the sample collection point was formed, in contrast to the coarse aggregate content, in which profile can be clearly seen a concentration of gravels at the extreme points, at the commencement and the end of the sample collection. Regarding its consistency, on the whole, there was a reduction from the initial and to the end point, respecting the regulations standards.