Submitted in fulfillment of the academic requirement for a degree in Doctor of Philosophy (Ph.D.) in Food Science and Technology, Durban University of Technology, Durban, South Africa, 2017. / There has been a global increase in fresh produce consumption, due to its attendant nutritional a nd health benefits. On the other hand, increase in the outbreak of diseases, accompanied with health and economic implications, have been traced to this deve lopment. A good number of pathogenic contaminants along the food chain have been identified as causative agent s with Listeria monocytogenes identified as one of such. Among other control strategies, the use of bacteriophage, was recommended as a palliative measure. Furthermore, the a ppli cation of artificial neural networks (ANN) in food safety remains an emerging concept in risk assessment study. Therefore, the aim of this research is to investigate the effect of bacteriophage or phage control and artificial neural network prediction in the inactivation of L. monocytogenes ATCC 7644 on fresh produce. Fresh-cut tomato and carrot were artificially inoculated with L. monocytogenes (108 CFU/ml) and subjected to antimicrobial treatment of Listex P100 bacteriophage (108 PFU/ml), sucrose monolaurate (SML at 100, 250 and 400 ppm), with chlorine (sodium hypochlorite at 200 ppm) used as control. Also, application of ANN to predict the risk effect of antimicrobial treatments of bacteriophage, sucrose monolaurate and chlorine was evaluated on the fresh-cut produce. Mathematical models were developed using a linear regression and sigmoid (hyperbolic and logistic) activation function-(120). Data sets were trained using Back propagation ANN, containing one hidden layer with four hidden neurons. Furthermore, carbon utilization profile of phage-treated L. monocytogenes using phenotypic micro array method was evaluated. In the first phase, susceptibility of L. monocytogenes subjected to certain stress-adapted conditions (acid,-adapted AA, chlorine-adapted CA, heat-adapted HA) and non-adapted-NA to phage treatment inoculated on the fresh-cut produce stored for 10 days at 4, 10 and 25oC was evaluated. The second phase investigated the combination of bacteriophage and sucrose monolaurate (using chlorine at 200 ppm as control) to inhibit the L. monocytogenes growth on the fresh-cut produce stored for 6 days at 4, 10 and 25oC. Physicochemical properties (pH, titratable acid-TTA, total soluble solids-TSS, and colour values-CIE L* a* b*) of the fresh produce after treatment were evaluated. In the third phase, ANN as a predictive tool was used to evaluate the risk involved in the relationship among the initial bacterial load, fresh-produce type, antimicrobial concentration and residual bacteria. In the final phase, 100 µL of phage-treated L. monocytogenes was introduced into a 96-micro well plate impregnated with a tetrazolium dye. The Carbon utilization profile was evaluated at intervals of 4 hours for 48 hours using a biolog micro station. Generally, L. monocytogenes grew on both fresh-cut produce and the storage temperature did not adversely affect the lytic ability of the phage treatment. Antimicrobial treatment of phage and sucrose monolaurate had minimal variations on the physicochemical properties of both fresh-cut samples. All stress-adapted and non-adapted L. monocytogenes were (p ≤ 0.05) susceptible to bacteriophage control. Phage treatment reduced non-adapted, acid adapted, chlorine-adapted, and heat-adapted L. monocytogenes population by 0.57, 0.81, 0.86 and 0.95 log CFU/ml in fresh-cut tomato, and 2.26, 2.41, 2.49 and 2.54 log CFU/ml in fresh cut carrot respectively. Furthermore, the additive effect of SML at 100 and 250 ppm had no significant effect on phage lysis. However, combination of phage with SML at 400 ppm significantly (p ≤ 0.05) resulted in 1 and 3 fold reductions in tomato and carrot respectively. Control treatment with chlorine resulted in 1-2 log reductions on both fresh produce. Algorithm data set trained using ANN gave 100% accuracy. Prediction with logistic activation function showed the highest positive correlation relationship between predicted and observed values with ~ 0.99 R2-value and MSE of 0.0831. Carbon utilization profile showed hexose and pentose sugars-ribose, glucose, fructose and sugars were maximally utilized while oligosaccharide sugars of sucrose, cellobiose and gentiobiose were similarly observed to be utilized. Notably, utilization of glucose-6-phosphate which determines L. monocytogenes pathogenicity was not very pronounced in the carbon profile. Bacteriophage application in the inactivation of L. monocytogenes contamination of fresh produce provides a safe means of control. Its perceived limitation however, can be overcome by combining with other antimicrobials. Similarly, the use of artificial neural networks prediction, remains an improved approach to harness the potential risk that could occur through this method. / D

Malgré leur existence ancienne et leur incidence dans la zone intertropicale, aucun traitement efficace, autre que symptomatique, n’est disponible à l’heure actuelle pour traiter les intoxications ciguatériques. La médecine traditionnelle à base de plantes vient alors au secours des populations. Dans la région du Pacifique, une des plantes les plus utilisées, et présentant des potentialités dans le traitement de la ciguatéra, est Heliotropium foertherianum Diane & Hilger. Toutefois, cette plante, de la famille des Borraginacées, est connue pour produire des alcaloïdes pyrrolizidiniques, composés hépatotoxiques. Dans ce travail, l’activité biologique sur cellules neuronales et la composition chimique d’H. foertherianum ont été étudiées, en vue d’une valorisation d’un extrait de cette plante. Dans un premier temps, la confirmation de l’activité biologique in vitro de l’extrait aqueux d’H. foertherianum et de ses principes actifs, les acides rosmarinique et caféique, a été apportée. Ensuite, la caractérisation chimique de l’extrait aqueux par CLHP-SM a mené à l’identification potentielle de 25 composés et à la vérification de l’absence des alcaloïdes pyrrolizidiniques. Enfin, l’étude des paramètres de récolte, de conservation et d’extraction des feuilles et extraits a permis de détailler les conditions nécessaires à l’obtention d’un extrait à la teneur maximale en principes actifs dont l’activité biologique serait garantie. Ainsi, la production locale d’un extrait d’H. foertherianum, dosé en principes actifs et dont l’innocuité est vérifiée, en tant que traitement contre les intoxications ciguatériques peut être sérieusement envisagée. / Despite its former existence and its impact in the intertropical zone, no effective treatment, other than symptomatic, is available to treat ciguatera fish poisoning yet. People can only rely on traditional herbal medicine. In the Pacific region, one of the most used plants, which is promising for the treatment of ciguatera fish poisoning, is Heliotropium foertherianum Diane & Hilger. However, this plant, from the Boraginaceae family, is known for producing hepatotoxic compounds such as pyrrolizidine alkaloids. In order to valorize this plant extract, its biological activity on neuronal cells and its chemical composition with the means of HPLC-DAD and HPLC-MS have been studied in this work. First, the in vitro biological activity of the aqueous extract of H. foertherianum and its active principles, rosmarinic and caffeic acids, was confirmed. Then the chemical characterization of the aqueous extract led to the possible identification of 25 compounds and the verification of the absence of pyrrolizidine alkaloids. Finally, the study of the harvest, conservation and extraction parameters of leaves and extracts permits to specify the conditions needed for obtaining an extract with high level of active principles and whose biological activity is guaranteed. Therefore, a local production of an extract from H. foertherianum as a treatment against ciguatera fish poisoning, dosed in active principles and whose safety is established, can be seriously considered.

Over the last few years, the town of La Oroya, in Perú’s central Andes has received significant international attention due to the alarming number of children suffering from high levels of lead poisoning as a result of pollution from the town’s smelter. Paradoxically, instead of collectively unifying voices to claim the protection of their health and environment, a significant portion of members of this community opted to minimize the problem with the purpose of defending job opportunities at the smelter.This dissertation examines the deep structural causes that have placed residents of this community in the difficult position of having to sacrifice their human right to health in order to preserve their right to work at the smelter. I argue that the La Oroya community acquiesced in forfeiting their own rights because they have been historically trapped in a “context of systemic unfreedom.” This is a historically formed and politically and economically reproduced context of human rights abuses, a context that affects the overall well-being of individuals and communities, and diminishes their ability to challenge such abuses and transform their realities. To assess the exact contours and components of the context of systemic unfreedom in La Oroya, and respond to the question of how this context has encouraged the trade-offs of health for work, I have designed a “capability-oriented model of human rights.” Conceptually, this model builds upon structural approaches to human rights proposed by authors such as Paul Farmer, Tony Evans and Mark Goodale. It also adopts Séverine Deneuline’s relational-political interpretation of the capability approach pioneered by Amartya Sen. Methodologically, a salient feature of my model is its incorporation of voices of affected community members as an important source of knowledge. Results of this study show the extent to which the context of systemic unfreedom in La Oroya has been sustained by the interconnection of a constellation of factors: environmental (historical pollution); institutional (economic dependency, the state’s leniency in enforcing the smelter company’s environmental obligations, the extraction-based model of economic development in Perú, the institutional fragility of the human rights discourse); social (migration, loss of collective identity, socio-economic and gender inequalities, uncertainty about pollution, limited access to information, assignment of responsibility for pollution-based illness to individuals, stigma against the poor); and personal (individual values and needs, characteristics of individual identity). These factors have converged over time and intersected at the macro, meso and micro levels, trapping residents from La Oroya in a vicious cycle of disadvantage. I conclude by suggesting that, in order to effectively address “systemic unfreedom” in this smelter town, both short-term and long-term solutions are required. That is, in addition to promoting the completion of proposed environmental mitigation and soil remediation plans in La Oroya, I offer suggestions towards reversing entrenched socio-economic and gender inequalities and reconstituting a collective community identity. Fundamentally, the ultimate goal of structural transformation in La Oroya requires addressing current patterns of power, economic dependency, and domination, thus fostering changes in the state’s vision of development. / Graduate / 2016-04-30

Magister Public Health - MPH / This study is aimed to assess the extent of street food vendor information and education on food safety. Aim: To determine the knowledge, attitudes and practices (KAP) of street food vendors, within the City of Johannesburg, with regard to food hygiene and safety. Methods: A descriptive, cross-sectional study utilizing a quantitative research approach. Data was collected through face-to-face interviewing of street food vendors, with observations of general hygiene and cleanliness. Data was captured in Excel and imported into CDC Epi Info version 3.4.3 (2007) for analysis. Numerical data was analyzed using descriptive statistics and categorical data was analyzed using frequencies. Bivariate analysis was used to establish differences between regions with high and low proportions of street food vendors with regard to knowledge, practices and attitudes variables. / South Africa

L’empoisonnement est une infraction qui est apparue tardivement, bien que le poison soit depuis longtemps utilisé comme une arme criminelle redoutable. En 1682, il fait l’objet d’une réglementation spécifique qui le distingue du simple homicide et qui encadre de manière rigoureuse le commerce des substances vénéneuses. Depuis cette date, l’empoisonnement a toujours été incriminé de façon autonome dans le droit français. Aussi, cette nouveauté juridique soulève de nombreuses questions d’une part sur la constitution de l’infraction et, de l’autre, sur sa répression par les tribunaux. L’empoisonnement étant un crime difficilement démontrable, la question de la preuve se pose à chaque instant. Par conséquent, il faut interroger la justice criminelle pour comprendre l’apport de cette nouvelle législation et les spécificités qui sont propres au crime d’empoisonnement, tant dans le déroulement de la procédure criminelle que dans la sanction appliquée aux empoisonneurs. / Poisonning is a violation which appeared lately, though poison has been used as a powerful criminal weapon for a long time. In 1682, a specific regulation distinguished it from a manslaughter and supervised the trade of poisonous substances in a rigorous way. Since then, the poisoning has always been incriminated independantly in the French law. So a lot of question was raised by this new law ; in one hand on the constitution of the breach and on the other hand on its repression by the courts. As poisonning is a crime which is hard to proove, evidence have to be found all the time. Therefore, we have to ask the Criminal Justice to understand this new legislation and these specificities which are particular to poisonning, both in the progress of the criminal procedure and in the penalty applied to the poisoners.

Lead is a serious developmental neurotoxin with the capacity to interrupt brain development and impair functioning. Since at least 1930 numerous case studies in American, Canadian and Australian literature have identified lead based paint in the home as a source of poisoning for young children; and since at least 1990 evidence has shown that it is the lead dust from deteriorating paint in older homes and renovating activities that is the primary source of chronic exposure for young children today. Not much is known about the extent of childhood lead poisoning in Canada. Gaps in our understanding include a lack of national survey data on childhood blood lead levels and an absence of reliable data to determine the era of housing that poses the greatest risk. This thesis posits that despite this paucity of research knowledge there is evidence to suggest that populations of vulnerable children continue to be harmed by exposure to historic sources of lead, such as lead-based paint found in older housing stock. This thesis examines the evidence to support this contention by critically analyzing the Canadian public health response to the issue of childhood lead poisoning. Specific attention is paid to discourse corresponding to lead-based paint, the putative major pathway of exposure for children ages 1 to 5 years. Using Foucault’s genealogical/archaeological approach, as elaborated upon by Rawlinson (1987) this thesis discusses the socio-political and economical processes that shaped health care knowledge regarding childhood lead poisoning in Canada and influenced the way knowledge was produced and used by health care providers and policy makers. The analysis is assisted via a comparison of Canadian public health discourse with American discourse, with an emphasis on discourse appearing in the post leaded gasoline era (1990-2008). The strength of a Foucauldian archaeological/genealogical analysis for nursing research and particularly for this analysis is in its focus on discourse, surfaces of emergence, transformations, mutations, contingencies, events, recognition of power/knowledge strategies, descriptions of discipline technologies and consequences, and suggested possibilities of resistance. This thesis proposes that surveillance data constituted both a product and acatalyst of the dominant view on childhood lead poisoning occurring from residential sources and posits that a lack of Canadian context specific surveillance data was the major “policing” factor limiting Canadian public health discourse. Further, privileged access to blood lead survey data maintained the view that childhood lead poisoning was a problem of the past or an American problem. Third, tensions among Canada’s two federal agencies which hold primary responsibility for lead, health and housing resulted in a weakened response whereby, to date, no legislation exists to protect vulnerable populations of Canadian children from exposure to historic sources of lead in residential dwellings.

(English) Background: Methanol poisoning is severe medical condition with a need of urgent intensive treatment. Mass poisoning outbreak took place in the Czech Republic in 2012-2013. Costs of hospital treatment of methanol poisoning present significant financial burden to healthcare systems. The effect of treatment modality choice on clinical outcome and healthcare costs is not known, as well as its impact on the quality of life of methanol poisoning survivors after hospital discharge. Aim: To compare different therapeutic methods, choice of antidote (fomepizole versus ethanol) and extracorporeal elimination method (intermittent vs. continuous dialysis) for optimizing clinical outcome, cost-effectiveness, hospital costs, post-discharge costs, and the quality of life in survivors. Methods: For prospective cohort study, all patients hospitalized with acute methanol poisoning were included (n=106); for hospital and one-year healthcare costs study, all survivors of acute methanol poisoning (n=83) were included. For longitudinal quality of life study all survivors with informed consent (n=54) and control group of chronic alcohol abusers, age- and gender-balanced, without history of methanol poisoning (n=23), were included. Results: Comparative data of clinical effectiveness of elimination techniques...

In this thesis, we present the investigation of influence of methanol crossover, which significantly decreases the performance of DMFC (Direct Methanol Fuel Cell). Additionally the poisoning effect occurs on the cathode side. The durability of cathode catalyst exposed by methanol vapor is studied. Moreover, the regene- rative behavior after exposition has been found. The comparison of commercial catalyst with our own sputtered Pt and PtCo and PtRu thin layers as cata- lyst is presented. Obtained results have shown that PtCo is reasonable compro- mise between pure Pt, which has high performance, and PtRu, which is tolerant to methanol poisoning. Future research should further evaluate the advantages of PtCo cathode catalyst prepared by standard procedures and its market poten- tial in comparison with PtRu. 1

Worldwide, pesticides are applied to protect crops against insects, fungi and other parasites. Without these chemicals it would not be possible to produce sufficient food to satisfy the demand of an ever-increasing world population. Unfortunately, many cases of accidental and intentional poisoning of humans and animals occur and the objectives of this study were to obtain statistics of aldicarb poisoning in companion animals in Gauteng Province and to evaluate hydroxypropyl-<font face="symbol">b</font>-cyclodextrin as a potential treatment. Cyclodextrins are ring-shaped oligosaccharides with a hydrophilic exterior and a hydrophobic interior. The interior cavity is capable of complexing fat-soluble molecules small enough to fit inside. Aldicarb is moderately lipid-soluble, non-ionized and of low molecular weight and thus fits all criteria for complexation with cyclodextrin. Questionnaires were posted to all private practitioners in Gauteng. The survey was designed to determine the percentage of aldicarb cases seen, clinical signs observed, treatment regimen, proposals for preventative actions and more effective treatments. Other questions included duration of treatment, survival rate, cost to client, post-mortem findings and reasons for poisonings. Thirty-four percent of respondants indicated the total number of all clinical cases presented at their practices during 2003. The percentage of suspected aldicarb cases as a proportion of all cases ranged from 0.05 - 2.6 % for dogs and 0.09 - 3.33 % for cats. Only 26.5 % of practitioners sometimes submitted samples for laboratory confirmation of aldicarb poisoning. Salivation and tremors were the most common clinical signs observed by private practitioners and the majority of suspected poisoning cases were treated with atropine, intravenous fluid and electrolyte therapy and the oral administration of activated charcoal. Thirty-three respondents thought that there was an increase in the number of aldicarb cases, but 35 felt there was no increase during 2003. Fifteen respondents were reluctant to venture an opinion. Most veterinarians indicated that criminal intent was the main reason why animals were poisoned and 95 % of respondents reported that it occurred throughout the year, but an increased incidence was observed during holiday periods.Survival times in the majority of rats dosed with aldicarb and receiving intravenous cyclodextrin were longer, compared to the control rats only dosed with aldicarb per os. Rats receiving cyclodextrin immediately before aldicarb, survived longer when compared to rats, which received aldicarb prior to cyclodextrin. / Dissertation (MSc (Paraclinical Sciences))--University of Pretoria, 2005. / Paraclinical Sciences / unrestricted

Locoweed poisoning, caused by ingestion of certain species of Astragalous and Oxytropis, has had serious economic impacts through a loss of productivity in livestock. This study has attempted to evaluate losses suffered by livestockmen grazing their cattle on areas infested with locoweed species. The results indicate a serious economic impact on these individuals. Personal interviews were carried out with five cattle ranchers faced with typical locoweed problems. These beef cattle operations were located in Utah, Wyoming, and New Mexico. All of these producers described similar problems and losses due to locoweed poisoning. Information obtained from these interviews was used to estimate a 1978 dollar loss for three ranches, running in common, and located near Park Valley, Utah. This study found the problem areas to be: (1) reduced weaning weights of calves; (2) increased requirements in the number of replacement heifers; (3) an increase in death loss; (4) reproductive problems (abortions and infertility); and (5) increased costs associated with labor and management problems. The summation of economic losses in each of these problem areas reflected a total estimated loss of $30,689.02 in 1978. To determine if locoweed poisoning had long-range effects on weight gains, a sample of 20 calves were put on a 138-day feeding experiment. Of these 20 calves, 12 had grazed a locoweed-infested area, while the remaining 8 had no access to the plant. Overall average gain of both groups was found to be nearly identical. This indicates that animals will recover with proper but, sometimes, costly management. Profitability of spraying locoweed-infested ranges with 2,4-dichlorophenoxy acetic acid (2,4-D) was determined through information supplied by the Wyoming rancher. An internal rate of return of 39.4 percent was found by using this method of locoweed control in this particular instance. Ranchers interviewed in this study estimated their losses due to locoweed poisoning to be from 30 to 40 percent reduction in profit. Although profit margins were not determined, the estimated loss of $30,689.02 found in this study would be close to their determination. With the rampant increase in operating costs which have occurred in the past decade, producers could not long endure losses of this magnitude. However, it was determined that with proper plant control and management these losses could be substantially reduced.