With a primary focus on Health Canada (HC) and the Canadian Food Inspection Agency (CFIA), this thesis describes the state of microbial related public involvement and risk communication undertakings. The findings show that HC engages with experts to a far greater extent than with the lay public and that HC has not upheld its stated commitment to transparency. Furthermore, both HC’s and the CFIA´s approach to risk communication is overly general, has failed to provide opportunities for dialogue with vulnerable groups and is not rooted in foodborne surveillance data. Public involvement in food safety governance would be improved if HC provided the lay public with a seat on advisory committees and improved its reporting methods. HC and the CFIA could also make improvements by creating opportunities for dialogue between officials and the general public, and by exploring the potential use of alternative risk communication vehicles, such as food labels.

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This thesis examines the important and topical issue of food safety among member states of the European Union. After tracing the development of related legislation, a review of the literature focuses on its management within the European hotel industry. In attempting to account for differences in attitudes and practice towards food safety, the study explores the respective application oftwo opposing theoretical positions. The first, known as divergence theory, which tends to equate culture with nationality, maintains that variation is attributable to inter-country differences in norms and values. The second, convergence theory, argues that culture is more appropriately understood in the organisational sense as functioning at the corporate level of the hotel. Hence, under the latter perspective, an explanation of variance is more likely to be derived from differences in type or ethos of hotel (whether chain or independent) and the ways that they are structured according to mode ofoperation, size and hierarchy. After outlining the methodological difficulties of carrying out a comparative study capable of resolving the foregoing dilemma, the empirical section takes place in two major stages: (1 ) a canvassing of expert opinion, with a view to filling gaps in knowledge of the legislation and its implementation; and (2) the conducting of a sample survey among hotel personnel in a number of EU member states (this stage being preceded by a small, two-phase pilot investigation). In order to contrast the rival theories statistically, the data from the survey are analysed by a series of relevant independent variables and tested for significance. Although there are acknowledged limitations on the degree of generalisation that can be claimed, by and large the convergence theory is upheld. A summary of the findings is provided and a number of implications for the future of food safety legislation in the EU are highlighted.

Anyone can upload news instantaneously to Twitter in 140-characters or less, therefore it is important to assess the credibility of tweets, particularly during a foodborne illness outbreak. According to a Microsoft study there are numerous Twitter features that impact the credibility of tweets. This study examines students’ use of Twitter, and their perceptions of how features and sources impact the credibility of tweets related to a foodborne illness. An online survey was completed by Texas A&M University students classified as U3 juniors (N = 200) in social science-based majors in the College of Agriculture and Life Sciences. The study revealed students to be moderate users of Twitter. Eight features were identified to impact credibility: verified author topic expertise, account has verification seal, tweet contains grammar/punctuation mistakes, author is someone you’ve heard of, author is often mentioned/retweeted, author often tweets on topic, and author has many followers. Three Twitter identities a professor, student, and student organization, were created to measure tweet credibility. Tweets from the professor were perceived more credible than tweets attributed to student or student organization. The results indicated statistical differences between features attributed to each source. These findings can help sources determine what features can make tweets the most credible. This study has important implications for organizations that engage consumers on Twitter when breaking news such as a foodborne illness outbreak occurs.

To determine the impact of stress response on enumeration, cell association status and the viability of Escherichia coli DH5, Staphylococcus aureus ATCC 13565 and Listeria monocytogenes CDC 7762 were evaluated using fluorescence microscopy and were compared with the outcomes of traditional plate count and optical density measurements. Fluorescence microscopy revealed that organic acid stress (acetic and lactic, pH 2.7-3.3) induced cell clumping with little loss of viability in Escherichia coli DH5. Significantly lower values for cell enumeration were found for plate counts and OD600 measurement, likely due to cell clumping in response to organic acid stress. Gram-negative bacteria Escherichia coli DH5 showed higher levels of clumping and subsequent resistance against organic acid stress. Increased cell surface hydrophobicity was found in cells that exhibited more evident clumping. However, inorganic acid stress (hydrochloric and sulfuric, pH 3.0-3.3) induced only very low level of clumping in stationary-phase Escherichia coli DH5 and almost no clumping in other cultures. Osmotic stress, heat and cold shock were not found to induce cell clumping. It has been determined that traditional enumeration methods have significantly underestimated the number of viable bacterial cells when organic acid stress is involved. Plate counts and OD600 measurement therefore need to be reassessed as tools for accurate evaluation of pathogens in food industry. / Food Science and Technology

Nisin is a bacteriocin produced by Lactococcus lactis subsp. lactis, which is active against Gram-positive organisms including bacterial spores. It is not generally active against Gram-negative bacteria, yeasts and fungi. Gram negatives show nisin-sensitivity when their outer membrane permeability is altered by various means, such as treatments with chelators, e.g. EDTA, osmotic shock, heating, freezing, freeze-drying, high- pressure etc. Application of chelators and nisin is effective against Gram-negatives when exogenous nisin is added. Nisin produced in situ and chelators are not an effective combination, since nisin production follows the pH drop caused by sugar fermentation, and this interferes with the sequestering ability of the chelators. Presence of nisin during thermal inactivation of Gram-negatives though is effective. Bacteria become structurally injured during heating showing sensitivity to agents like SDS and deoxycholate and extended detection times by impedimetry. These injured bacteria are inactivated by nisin, with a concomitant reduction of the measured D-values. Low pH and the presence of small amount of chelators enhance the injury and inactivation and reduce D-values further. Gram-negative bacteria injured by chilling and freezing are also sensitive to nisin. The effectiveness of nisin is reduced in a food environment mostly of nisin binding to fat, and food particles. D-values were decreased less or not at all in egg white and liquid whole egg, respectively, and rapid chilling of bacteria attached to chicken skin in presence of nisin did not give the effect seen in laboratory media. Nisin is active against heat-, chill-, and freezing-stressed Gram-negatives only if it is present during the treatments. When the stress factor is removed, the bacteria recover their nisin resistance, implying transient susceptibility to nisin, but not to smaller molecules. This is probably due to rapid reorganisation and restoration of OM permeability damage, rather than biochemical repair. The LPS chain length influences the sensitisation of Gram-negatives to nisin, only in the case of freezing, where the strain with the shorter LPS chain was more sensitive than the wild type. Heat-, and freezing-stressed bacteria lost lipopolysaccharides and increased their cell surface hydrophobicity. This was not seen with chill-stressed bacteria, which were sensitive to nisin though. This indicates that release of LPS is not a prerequisite for nisin sensitivity in Gram-negatives.

Master of Science / Food Science Institute / Fadi M. Aramouni / Since the Food Safety Modernization Act (FSMA) was signed into law in 2011, the government has taken huge strides toward making the food safety system preventive rather than reactive. Specifically, the Preventive Controls for Human Food (PCHF) final rule has required collaboration from government officials, educational institutions, industry professionals, and stakeholders to assist in the rulemaking, education, and implementation of the new rule. The rulemaking process for the PCHF final rule took 4 years to finalize. The Food and Drug Administration funded a grant to the Illinois Institute of Technology’s Institute for Food Safety and Health (IIT IFSH) to help create an educational program about food safety risk-based preventive controls. Since then, the Food Safety Preventive Controls Alliance (FSPCA) has been coordinating training programs to certify food professionals as Preventive Controls Qualified Individuals (PCQI). After gathering minor statistical evidence through course evaluations for 10 FSPCA facilitated education programs, extension personnel of the Food Science Institute at Kansas State University found that the educational materials are a big help to those in industry and in regulatory agencies.

Lupane and Hwange districts fall under natural region IV and V and lie in the semi-arid regions of Zimbabwe with low and erratic mean annual rainfall not exceeding 600mm. Seventy percent of Zimbabwe’s population lives in communal areas, whose livelihood is based on agriculture. The communities in these areas mainly practice mixed farming systems. However, crop production is constrained by water availability and suitable production techniques. As a result households in these areas are experiencing worsening levels of household food insecurity. Two irrigation schemes were identified for this study and these are located in these two districts. Tshongokwe irrigation scheme is located in Lupane district and Lukosi irrigation scheme is located in Hwange district and these irrigation schemes are about 25 hectares in size. Lupane and Hwange districts are considered to be one of the most food insecure areas in the country because of the frequent droughts and unreliable rainfall in the region. The major tool of enquiry in this study was the questionnaire which was used to collect data from the households that farm on irrigated land and those that farm on dryland farming. Household and farm characteristics were collected using structured questionnaires with the help of locally recruited and trained enumerators. Agricultural production, household consumption and marketing of agricultural produce were accessed using the questionnaire to establish problems experienced by farmers. The main objective of this study was to investigate the determinants of household food security using a logistic regression model. The model was initially fitted with thirteen variables, selected from factors identified by previous researchers that affect food security in communal areas. Six variables were found to be significant at 1, 5 and 10 percent significance level and all had the expected signs except farm size. These factors include access to irrigation, farm size, cattle ownership, fertilizer application, household size and per capita aggregate production. The results obtained were further analyzed to compute partial effects on continuous variables and change in probabilities on the discrete variables for the significant factors in the logistic regression model. Analysis of partial effects revealed that household size, farm size, cattle ownership and per capita aggregate production lead to a greater probability of household being food secure. Change in probability results showed that having access to irrigation and using fertilizer can increase the probability of household being food secure The findings of this study highlight a positive and significant relationship between access to irrigation, fertilizer application, cattle ownership, per capita aggregate production to household food security. Household size and farm size have a negative and significant relationship on household food security. This study shows the effectiveness of irrigated farming over dryland farming in the semi-arid areas. The results show increased agricultural production, crop diversification and higher incomes from irrigation farming as compared to dry land farming. Irrigation farming has enabled many households to diversify their source of income and generate more income. Irrigation has enabled households with irrigation not only to feed themselves throughout the year but also to invest on non-agricultural goods and services from incomes received from crop sales Based on the results from the logistic regression model, it can be concluded that household size, farm size, per capita aggregate production, cattle ownership, fertilizer application and access to irrigation have a positive effect on household food security and the magnitude of changes in conditional probabilities have an impact on household food security.

Listeria monocytogenes is the etiological agent of a life-threatening, opportunistic infection caused by the ingestion of contaminated foods. Although L. monocytogenes is divided into 13 serotypes, 98% of human illness is caused by serotype 1/2a, 1/2b and 4b strains, with serotype 4b accounting for almost all the major outbreaks of human listeriosis. The principle objective of this work was to develop surface-binding monoclonal antibodies (MAbs) highly specific for serotype 4b, as well as characterize their antigen targets to aid in the detection and isolation of serotype 4b strains using an antibody based procedure. To create such antibodies, mice were immunized with formalin killed whole cells of L. monocytogenes serotype 4b strain LI0521. A total of 15 MAbs reactive to serotype 4b isolates were shown to recognize a ~77 kDa surface antigen subsequently identified by mass spectrometry as surface associated autolysin, IspC. Epitope mapping experiments further revealed that each of the 15 MAbs bound to the cell wall binding GW domain of IspC and can be essentially divided into 4 major groups based on epitope localization. ELISA analysis of the reactivity of each of the MAbs with various L. monocytogenes serotypes indicated that several MAbs were 100% specific for serotype 4b isolates. Surface plasmon resonance experiments showed that the affinity constants for each of these MAbs fell within the range of 1.0 x 10-7 to 6.4 x 10-9 M. To determine whether IspC, shown to be well conserved among various serotype 4b strains, is a useful diagnostic marker with antibody-based methods, the expression of IspC was assessed in L. monocytogenes cultured under normal and stress conditions. A functional promoter directing the transcription of ispC gene was identified immediately upstream of the ispC open reading frame by constructing the promoterless lacZ gene fusion with the putative ispC promoter region and by 5'RACE analysis. Data obtained with the lacZ reporter gene system and immunofluorescent microscopy revealed that IspC is expressed on the cell surface under all growth conditions tested (temperature, osmotic stress, pH, ethanol, oxidative stress, anaerobic conditions, carbon source and enrichment media) that allow for cellular division, although the level of ispC gene expression varies. In addition, a significant effort were put into elucidating the hydrolytic bond specificity of IspC by HPLC and mass spectrometry analysis of muropeptides released from IspC-mediated hydrolysis of L. monocytogenes peptidoglycan (PG). The results demonstrated that IspC functions as an N-acetylglucosaminidase capable of cleaving the β-1,4-glycosidic bond of the PG glycan strand. Furthermore, IspC was more efficient at hydrolysing fully Nacetylated PG from a PG deacetylase gene (pgdA) deletion mutant of L. monocytogenes than partially de-N-acetylated wild-type PG, indicating that modification of PG by de-Nacetylation of GlcNAc residues renders PG resistant to IspC hydrolysis. In conclusion, the surface autolysin IspC with the N-acetylglucosaminidase activity is a novel diagnostic marker for the 4b serotype strains, which can be explored , in conjunction with specific MAbs developed here, for detection and isolation of L. monocytogenes serotype 4b strains directly from food, environmental and clinical samples with the need for minimal or no culture enrichment.

The objective of this dissertation was to (1) determine which grow-out and processing sampling points best predicts and causes Campylobacter later in production (2) identify risk factors within the hatchery that influenced Campylobacter prevalence later in production (3) identify biosecurity risk factors that were associated with Campylobacter presence during production and processing (4) identify farm and production characteristics that were associated with Campylobacter presence later in production, and (5) to estimate the proportion of variance and the intraclass correlation coefficients within the hierarchical levels (complex, farm, bird) of the data. The best predictors of post-chill Campylobacter carcass status were the exterior whole carcass sample in the grow-out environment and the crop upon arrival at the processing plant. The best post-chill causal model contained the grow-out whole carcass. Variables associated with the increased odds of a Campylobacter positive sample included controlling the humidity in the hatchery chick room, 2-4 people handling the chicks at the hatchery, washing the setter twice yearly, 2 or more breeder farms providing eggs for the sampled flock, using low water pressure when washing the hatch trays, having more walk-in doors on the boiler house, the farmer removing the litter from the farm, concrete at most used door of the broiler house, the number of workers that work with the birds during grow-out, having more houses on the farm, standing water on the farm day 1, wood interior walls, a vegetation surface next the house footing, and 6 or less flocks on the litter. Protective factors included the use of footbaths and dedicated shoes, greater frequency of entering the house during brooding, disinfectant added to the drinker lines, having concrete outside the most used door, the cleanliness of the workroom, and harvesting birds at 56-63 days of age. The highest percent of variance occurred at the farm level meaning intervention efforts should focus on factors at the broiler farm level i.e. factors that are different among farms within a broiler complex.