No description available.

No description available.

E. coli O157:H7 has been found to survive in dry sausages and cause disease. Isothiocyanates have been studied for their capacity to eliminate pathogens from foods and are attractive from the consumer perspective because of their natural origin. There is a need to better understand how isothiocyanates kill microorganisms and their behaviour in food matrices. It was found that glutathione and cysteine naturally present in meat can react with AIT, forming a conjugate with no or low bactericidal activity against an E. coli O157:H7. In addition, AIT presented higher anti-E. coli activity at lower pH values; therefore, it should be more efficient in acid foods. AIT was also found to inhibit the activity of thioredoxin reductase and acetate kinase; hence, enzymatic inhibition may represent a way in which AIT kills E. coli O157:H7. Mustard powder is used as a spice (active myrosinase) and/or binder (inactive myrosinase) in meat products. Both of these powders killed E. coli O157:H7 in dry fermented sausage. This was not expected since the powder lacking myrosinase is not able to produce isothiocyanates. Starter cultures and E. coli were found to consume significant amounts of glucosinolates. Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M (higher myrosinase-like activity) were compared against P. pentosaceus UM 116P + S. carnosus UM 109M for their ability in reducing E. coli viability in dry sausage. Sausage batches containing powders of hot mustard, cold mustard, autoclaved mustard and no powder were prepared. Both pairs of starters yielded similar results. Reduction >5 log CFU/g of E. coli O157:H7 occurred after 31 d for hot powder and 38 d for cold powder; there was no reduction in the control. E. coli O157:H7 itself has greater effect on glucosinolate degradation than either pair of starters, which may be more important in determining its survival. Autoclaved powder caused >5 log CFU/g reduction after 18 d. This may be the result of synergistic/additive interaction among E. coli O157:H7 myrosinase-like activity, the presence of newly formed/released antimicrobials in the autoclaved powder and the multiple hurdles present in the dry sausage. Autoclaved mustard powder has potential as a novel food ingredient for the meat industry.

Food safety events receive substantial media coverage and can create devastating economics losses for agribusiness firms. It is unclear what factors influence consumers’ purchasing decisions before or after a food safety event occurs. The objectives of this study is to identify these factors that influence purchasing decisions, determine how consumers respond to hypothetical food safety events, and compare these findings across different products and geographical regions. The data for this research was obtained from two surveys. One survey concerned fresh produce while the second focused on meat products. The SPARTA model, based on the Theory of Planned Behavior, is used to determine the impact of probable factors that influence consumers’ purchasing decisions. The result of this research suggests that consumers have clearly-defined levels of trust regarding sources of food safety information. In general, a food safety event occurring in the fresh produce market seems to affect purchasing decisions more than the same event occurring in the meat market. Comparison of findings across geographical regions is less clear. Agribusiness firms can use these results to form a base strategic response plan for food safety events.

No description available.

In the agri-food industry, carbon dioxide sensors can be used for process control, monitoring quality, and assessing safety. A carbon dioxide sensor was developed using poly aniline boronic acid (PABA) conducting polymer as the electrically conductive region of the sensor for use in the agri-food industry and was demonstrated for use in detecting incipient or ongoing spoilage in stored grain. The developed sensor dynamically detected up to 2455 ppm CO2 concentration levels. The performance of the sensor in measurements of low concentrations of dissolved CO2 was characterized using standard solutions of NAHCO3. The dynamic range for the detection of H2CO3 was 4.91X10-4 to 9.81X10-3 mol L-1. The dc resistance values decreased with increasing CO2 concentration indicating an increase of conductivity due to increase in the amount of protonation. The developed CO2 sensor was evaluated for the influence of temperature (by storing it at – 20°C and 0°C as well as at operating temperatures of +10°C to 55°C) and relative humidity (from 20 to 70%). Temperature dependence of sensor's resistance values were observed possibly due to the change in conduction mechanism at different temperatures. The variation in the resistance with humidity was curvi-linear and repeatable, indicating that humidity has a less pronounced effect on the sensor’s performance. The sensor’s response to changes in CO2 concentrations at various humidity and temperature levels was stable indicating that the sensor can detect CO2 levels under fluctuating environmental conditions. The response of the PABA film to CO2 concentration was not affected by the presence of alcohols and ketones, proving that the developed CO2 sensor is not cross-sensitive to these compounds which may be present in spoiling grain. The sensor packaging components were selected and built in such a way to avoid contamination of the sensing material and the substrate by undesirable components including grain dust and chaff. The developed conducting polymer CO2 sensor exhibited dynamic performance in its response, recovery times, sensitivity, selectivity, stability and response slope when exposed to various CO2 levels inside simulated grain bulk conditions.

Given the credence nature of food quality and food safety attributes, consumers cannot easily verify whether food is high quality or is safe to eat, thus they rely on abstract systems of regulation and quality signals such as brands to make informed consumption choices. In fact, trust is recognized as a rational strategy that reduces consumers’ uncertainty when purchasing goods with credence attributes. While trust in food is a topical issue in an era of increasingly complex food systems, how trust and more precisely brand trust affects consumers’ perceptions of food is a relatively new research area in food economics. This thesis aims to answer questions such as what drives trust in the actors within the Canadian food system (i.e. government, farmers, food manufacturers, and food retailers) and in food brands, and the relationship between that trust and consumer confidence in food quality and food safety. Previous studies on institutional and system trust have been carried out primarily in the sociology, marketing and political sciences disciplines, while a few studies in food economics have investigated the influence of institutional trust and reported the degree of public trust in market actors. This study extends previous research on consumer trust in the context of food by developing a conceptual model in which trust in the food system and brand trust are expected to evolve to public confidence in credence attributes and lead to consumer commitment to food brands. Inspired from a comprehensive synthesis of the literature on consumer trust, the theoretical background suggests that consumer confidence in food attributes is jointly determined by trust in the food system (system-based trust) and brand trust (product-based trust), and it is moderated by consumer characteristics (personal-based trust) – namely: risk, past consumption experience and ethically-motivated behaviour. As well, consumers are assumed to perceive an actor or a brand as trustworthy through the influence of four postulated dimensions of trust: perceived competence, credibility, benevolence and reputation. A Structural Equation Modelling (SEM) approach is used for the empirical analysis. Data were gathered through an online survey of consumers conducted across Canada in July 2012 focusing on fresh chicken and packaged green salad products. The results show that individually none of the postulated antecedents of trust (i.e. competence, credibility, benevolence and reputation) was a significant driver for trust, especially for packaged salad. Unlike previous research on institutional trust and brand trust that uses a number of separate dimensions to measure trust predominantly in non-food contexts, this thesis finds that trust in the food system and food products could be measured differently by taking into account the interactive effects of perceived competence, credibility, reputation and benevolence on public trust. As such, the findings suggest that Canadian consumers tend to trust brands of chicken and packaged salad when these products are perceived as high quality, are backed by credible information, have a good reputation and, at the same time, enhance consumers’ welfare. In fact, a brand cannot be perceived as high quality and safe to eat (brand competence) without containing transparent information signalling its quality and safety (brand credibility). Additionally, results reveal some apparent product-specific effects: brand trust matters in fostering consumer confidence in chicken but not for salad. Furthermore, trust in the food system as a whole appears to be more influential in leading to public confidence in credence attributes than trust in food brands in the case of chicken. As such, it appears that trust in actors within the food supply chain is more important than relying on individual products. As well, the analysis shows that while psychographic variables (risk aversion, past consumption experience) and some demographics (e.g. gender, education) moderate the relationship between trust in the food system and brands for chicken, this is not the case for salad. In terms of marketing implications, the results suggest that while brands are useful signalling mechanisms, trust in these brands is not the main driver for consumer confidence in credence attributes. Furthermore, the much stronger effect of system trust implies that decision-makers would benefit by investing in building trust relationships with the public. Transparent communication and credible assurances about the practices and the intentions within the food system could be a way to gain and maintain public trust and, ultimately, consumer confidence in food quality and food safety.

The problem of this study was to determine health care professionals' opinions and practices concerning foodborne illness and food safety education during prenatal care. Data were collected from Indiana health care professionals using a mailed questionnaire. The results found that 71.7% of respondents do not provide foodborne illness and food safety education during prenatal care, however, 80.6% would like to. Most of the respondents indicated that they do not have the time (71.4%), resources (57 1%), or knowledge (25.7%) to provide this information to patients. Many of the respondents indicated that they have not received information on foodborne illness during pregnancy and are unaware of the recommendations to provide this information during prenatal care. The opinion questions found that most agree that foodborne illness can be serious in pregnancy and would like to learn more about the risks of foodborne illness to pregnant women and the fetus. / Department of Physiology and Health Science

In the agri-food industry, carbon dioxide sensors can be used for process control, monitoring quality, and assessing safety. A carbon dioxide sensor was developed using poly aniline boronic acid (PABA) conducting polymer as the electrically conductive region of the sensor for use in the agri-food industry and was demonstrated for use in detecting incipient or ongoing spoilage in stored grain. The developed sensor dynamically detected up to 2455 ppm CO2 concentration levels. The performance of the sensor in measurements of low concentrations of dissolved CO2 was characterized using standard solutions of NAHCO3. The dynamic range for the detection of H2CO3 was 4.91X10-4 to 9.81X10-3 mol L-1. The dc resistance values decreased with increasing CO2 concentration indicating an increase of conductivity due to increase in the amount of protonation. The developed CO2 sensor was evaluated for the influence of temperature (by storing it at – 20°C and 0°C as well as at operating temperatures of +10°C to 55°C) and relative humidity (from 20 to 70%). Temperature dependence of sensor's resistance values were observed possibly due to the change in conduction mechanism at different temperatures. The variation in the resistance with humidity was curvi-linear and repeatable, indicating that humidity has a less pronounced effect on the sensor’s performance. The sensor’s response to changes in CO2 concentrations at various humidity and temperature levels was stable indicating that the sensor can detect CO2 levels under fluctuating environmental conditions. The response of the PABA film to CO2 concentration was not affected by the presence of alcohols and ketones, proving that the developed CO2 sensor is not cross-sensitive to these compounds which may be present in spoiling grain. The sensor packaging components were selected and built in such a way to avoid contamination of the sensing material and the substrate by undesirable components including grain dust and chaff. The developed conducting polymer CO2 sensor exhibited dynamic performance in its response, recovery times, sensitivity, selectivity, stability and response slope when exposed to various CO2 levels inside simulated grain bulk conditions.

E. coli O157:H7 has been found to survive in dry sausages and cause disease. Isothiocyanates have been studied for their capacity to eliminate pathogens from foods and are attractive from the consumer perspective because of their natural origin. There is a need to better understand how isothiocyanates kill microorganisms and their behaviour in food matrices. It was found that glutathione and cysteine naturally present in meat can react with AIT, forming a conjugate with no or low bactericidal activity against an E. coli O157:H7. In addition, AIT presented higher anti-E. coli activity at lower pH values; therefore, it should be more efficient in acid foods. AIT was also found to inhibit the activity of thioredoxin reductase and acetate kinase; hence, enzymatic inhibition may represent a way in which AIT kills E. coli O157:H7. Mustard powder is used as a spice (active myrosinase) and/or binder (inactive myrosinase) in meat products. Both of these powders killed E. coli O157:H7 in dry fermented sausage. This was not expected since the powder lacking myrosinase is not able to produce isothiocyanates. Starter cultures and E. coli were found to consume significant amounts of glucosinolates. Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M (higher myrosinase-like activity) were compared against P. pentosaceus UM 116P + S. carnosus UM 109M for their ability in reducing E. coli viability in dry sausage. Sausage batches containing powders of hot mustard, cold mustard, autoclaved mustard and no powder were prepared. Both pairs of starters yielded similar results. Reduction >5 log CFU/g of E. coli O157:H7 occurred after 31 d for hot powder and 38 d for cold powder; there was no reduction in the control. E. coli O157:H7 itself has greater effect on glucosinolate degradation than either pair of starters, which may be more important in determining its survival. Autoclaved powder caused >5 log CFU/g reduction after 18 d. This may be the result of synergistic/additive interaction among E. coli O157:H7 myrosinase-like activity, the presence of newly formed/released antimicrobials in the autoclaved powder and the multiple hurdles present in the dry sausage. Autoclaved mustard powder has potential as a novel food ingredient for the meat industry.