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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Cold Pasteurization Of Tender Coconut Water By A Batch And Flow Processes Using Glassbeads Coated With Phytochemicals Encapsulated Nano-Liposomes

Thomson, Jim 01 May 2018 (has links)
Tender coconut water (TCW) is one of most consumed natural energy drinks. Although it is widely available in tropical countries, because of its natural health benefits it is increasingly consumed in other parts of the world. Therefore there has been an increased requirement for packaging and shipping. TCW is highly susceptible to microbial contamination during extraction and packaging, requiring pasteurization. Thermal pasteurization leads to loss of flavor and color of coconut water. The purpose of this study was to test the feasibility of a non-thermal method of pasteurization of TCW using natural antimicrobials like curcumin, eugenol, and d-limonene with curcumin. The non-thermal pasteurization method was developed in two different processes, i.e. a batch and flow-filter process. Batch cold pasteurization process was conducted by suspending liposome encapsulated antimicrobials immobilized on glassbeads in TCW at 4oC by shake flask assay. Maximum Reduction of Listeria monocytogenes and Escherichia coli W1485 in pasteurized TCW were observed to be 5 log CFU per ml of TCW within 7 days of incubation under the presence of nano-liposomes containing 50 mM of curcumin, d- limonene or eugenol. There was no change in color and aroma of TCW after 1 month of storage at 4oC. the flow filter cold pasteurization process was developed using filter medium coated with nano-liposomes encapsulated antimicrobial leading to extended release of the natural antimicrobial curcumin to the coconut water in 4oC. Listeria monocytogenes and E. coli W1485 were used as model organisms to test effectiveness of cold pasteurization. Reduction of L. monocytogenes and E. coli W1485 in pasteurized TCW was observed to be 5.2 and 4.5 log10CFU/ml of TCW respectively within 17.25 min of incubation under the presence of nano-liposomes containing 50 mM of curcumin. There was no change in color and aroma of TCW after 1 week of storage at 4oC.
122

Making preparation of poultry and eggs safer for consumers: a focus on recipes and temperature

Maughan, Curtis A. J. January 1900 (has links)
Doctor of Philosophy / Human Nutrition / Edgar Chambers IV / Consumer food safety often is lacking, with many studies showing that we need to understand consumer behavior better and find new ways to provide information. The objective of this research was to better understand consumer food safety behaviors, find possible avenues for communicating food safety instructions to consumers, and determine how those avenues could work for demonstrating food safety today. Results from this research showed that two of the main potential avenues for communicating food safety instructions, namely recipes and cooking shows, were wholly lacking in good information and behaviors. A survey of egg dish recipes found that almost none contained temperature information, despite recommendations of food safety agencies. Observing celebrity chefs prepare food showed that every chef repeatedly had poor food safety practices which would lead to foodborne illness if followed by consumers at home. Two consumer studies were done with observers watching consumers prepare poultry and egg items. In the first study, consumers were asked to prepare poultry and egg items using both stovetop and oven methods. This study demonstrated that consumers do not follow many food safety behaviors, such as hand washing and using thermometers, and that those who used a thermometer were not better at reaching a safe temperature than those who didn’t use one. The second study had consumers prepare poultry items following a recipe, with half receiving food safety instructions on hand washing and thermometer use with their recipes. This study demonstrated that the addition of food safety instructions dramatically improved food safety behaviors in consumers. A separate study looked at the effect of changing lighting due to recent changes in efficiency regulations. This study found that some forms of modern lighting, such as LEDs, are more likely to make consumers think that poultry products are finished cooking before they are done, showing an even greater need for thermometer use. These studies present a message for the industry: food safety information and behaviors are lacking in consumers, but simple efforts such as adding food safety instructions to recipes can make consumers more aware of appropriate behaviors and improve their food safety.
123

Avaliação higiênico-sanitária e físico-estrutural dos supermercados de Ribeirão Preto, SP. / Assessment of the sanitary, hygienic, physical and structural aspects of the supermarkets of Ribeirão Preto, SP.

Dario Valente 21 December 2001 (has links)
Define-se supermercado como o local onde se pratica comércio varejista de mercadorias em geral, predominantemente de produtos alimentícios, em uma área de venda de 300 a 5000 m2. Embora responda hoje por cerca de 85,0% das vendas de alimentos no Brasil, esse setor permanece ainda muito pouco estudado, particularmente em relação aos aspectos sanitários. Em Ribeirão Preto, os supermercados representam o principal local de venda de alimentos para todas as classes sociais, ao mesmo tempo que vêm sendo causa de número crescente do total de reclamações feitas à Divisão de Vigilância Sanitária (Visa) do município. Esta investigação teve o objetivo de: avaliar as condições higiênico-sanitárias e físico-estruturais dos supermercados e hipermercados (área de venda acima de 5000 m2) de Ribeirão Preto, com vistas a classificá-los segundo essas condições; avaliar o cumprimento da legislação vigente; detectar áreas/condições de risco à saúde pública; recomendar medidas corretivas. O trabalho foi conduzido durante as inspeções de rotina da Visa, utilizando-se a Ficha de Inspeção de Estabelecimentos da Área de Alimentos (FIEAA) adotada no Estado de São Paulo, a qual padroniza os procedimentos de inspeção e divide os itens que serão inspecionados em cinco grandes blocos. Foram incluídos todos os 56 supermercados e os 2 hipermercados da cidade. Os percentuais de adequação para cada bloco foram: 32,2% para o bloco 1, correspondente à situação e às condições da edificação; 27,1% para o bloco 2, correspondente aos equipamentos e aos utensílios; 68,1% para o bloco 3, correspondente ao pessoal de produção, manipulação e venda; 35,9% para o bloco 4, correspondente às matérias-primas e aos produtos expostos à venda; 42,3% para o bloco 5, correspondente ao fluxo de produção/manipulação/venda e ao controle de qualidade. Assim, apenas o bloco 3 foi classificado como regular, ficando todos os demais como deficientes. Na classificação final dos estabelecimentos, 46 (79,3%) foram classificados como deficientes, 11 (19,0%) como regulares, e apenas 1 (1,7%), como bom. Apesar de se reconhecer a existência de algumas inadequações nos pontos de corte padronizados para a classificação dos itens estudados, concluiu-se que a situação exige intervenção rigorosa das autoridades sanitárias, para se fazer cumprir a legislação vigente. Recomenda-se a adoção de algumas adaptações à legislação, entre as quais a obrigatoriedade de inclusão, no corpo de funcionários dos supermercados, de profissional capacitado na área de alimentos, bem como a mudança dos critérios de classificação dos estabelecimentos, visando a uma maior racionalidade na programação de inspeções rotineiras da Visa. / The definition of supermarket is that of a place where retail market of general merchandise, mainly food products, is practiced in a sales area beteween 300m2 and 5000m2. Though it currently represents about 85% of food sales in Brazil, this sector still remains understudied, especially when it comes to its sanitary aspects. In Ribeirão Preto the supermarkets represent the main sales area of food for all social classes, at the same time that it has been the subject of an increasing number of complaints that have arrived at the City Division of Sanitary Surveillance (DSS). This investigation aimed to evaluate the sanitary, hygiene, physical and structural aspects of the supermarkets and hypermarkets (sales area over 5000m2) of Ribeirão Preto, to classify them according to these conditions, to evaluate the applicability of the legislation, to detect areas/conditions of public health risks and to recommend correction measures. The work was conducted during DSS´s routine inspections, using the guidelines for inspection of the food enterprises adopted in the state of São Paulo, which divides the subjects to be inspected in five big blocks. All of the city 56 supermarkets and 2 hipermarkets were included. The percentage of adequacy for each block were 32.2% for block a, corresponding to the situation and conditions of the edification, 27.1% for block b, corresponding to equipments and utensils, 68.1% for block c, corresponding to the production, manipulation and sales staff, 35.9% for block d, corresponding to the raw materials and products displayed for sales; 42.3% for block e, corresponding to the flow of production/manipulation/sales and quality control. Only block c was classified as regular, being the others considered as insufficient. In the final classification of the supermarkets, 46(79.3%) of them were considered insufficient, 11(19.0%) regular and only 1(1.7%) good. Although some inadequacies in the cutoff criteria for classifying the supermarkets are recognized, it becomes clear that the situation demands a rigid intervention of the sanitary authority in order to apply the existing legislation. Based upon the findings of this investigation, some recommendations can be done. Among them is the inclusion in the supermarket staff of an employee skilled in the food field, as well as a change in the criteria used for the classification of the supermarkets, aiming a higher rationality in the DSS programming of routine inspections.
124

Addressing and anticipating food safety challenges: Microbiology and policy frameworks for Shiga toxin-producing Escherichia coli (STEC) and Salmonella

Unruh, Daniel Alan January 1900 (has links)
Doctor of Philosophy / Food Science Institute / Sara E. Gragg / Justin J. Kastner / Food safety is a public health issue that demands coordinated scientific and policy solutions. Despite advancements in interventions and surveillance, Shiga toxin-producing Escherichia coli (STEC) and Salmonella spp. continue to cause outbreaks in a wide variety of food products. In light of these public health urgencies, both microbiological and policy frameworks are needed to address and anticipate future food safety challenges related to these pathogens. Laboratory-based techniques are used to address (1) whether common processing stresses change the susceptibility of STEC and Salmonella to food-grade antimicrobials, (2) whether differences in STEC attachment to beef tissue can inform intervention strategies, and (3) the efficiency of a combined sanitizer approach to reduce Salmonella on spinach. Salmonella Montevideo, Newport, and Typhimurium, and STEC O26, O45, O103, O111, O145, and O157:H7 were subjected to salt, acid, heat, freeze-thaw, alkaline and no (control) stress, and then challenged with the antimicrobials lauric arginate, citric acid plus hydrochloric acid, peroxyacetic acid plus acetic acid and hydrogen peroxide, lactic acid plus citric acid, and lactic acid. Growth/inhibition/no-growth was determined by absorbance values. While differences (p≤0.05) were observed between some of the stressors and controls, the minimum inhibitory concentrations (MICs) observed for both STEC and Salmonella were below maximum concentrations permitted by the United States Department of Agriculture (USDA). STEC serogroups were grown in nutrient-dense or nutrient-limiting media and inoculated onto lean or adipose, pre-rigor (warm) or chilled beef tissue. Loosely and firmly attached cells were plated onto MacConkey agar at several time points. When grown in nutrient-dense media, time × sample type (buffer versus homogenized sample) and sample type × tissue type (adipose versus lean) were significant (p<0.001). For nutrient-limited cells, tissue type was a significant main effect (p=0.0134). Spinach was inoculated with 5.0 log CFU/g Salmonella, dried, and submerged in a sodium bisulfate peroxyacetic acid (SBS-PAA) wash, a chlorine wash, or water for 2 min. Samples were stored for 0, 1, 3, 5, and 10 d, and populations were enumerated. When plated on xylose-lysine-tergitol 4 (XLT-4), SBS-PAA and chlorine washes achieved significant reductions (p≤0.05). When plated on XLT-4 plus tryptic soy agar (TSA) overlay, SBS-PAA was the most effective treatment, with a reduction of 1.77 log CFU/g (p<0.0001). Recognizing that microbiology studies ought to be combined with policy frameworks (and potential food safety solutions), policy analyses were performed to (1) evaluate and make recommendations about the resilience of the U.S. food system to catastrophic events and (2) thoughtfully—and innovatively—address so-called “unknown unknowns” (or disasters) and forecast future food safety vulnerabilities. The U.S. food system and its response to an intentionally-contaminated food product are analyzed through responsibilities of public, private, and third-sector actors. To address unknown unknowns and more strategically address future food safety problems, public and private actors ought to: (a) learn from the past (i.e., the German O104 outbreak), (b) target food groups of high and/or increasing consumption, (c) assess threats primarily rooted in other critical infrastructures, (d) borrow concepts and principles from meteorological forecasting, and (e) advocate multidisciplinary thinking.
125

Using the theory of planned behavior to explore restaurant managers support for employee food safety training

Roberts, Kevin R. January 1900 (has links)
Doctor of Philosophy / Department of Hotel, Restaurant, Institution Management and Dietetics / Elizabeth B. Barrett / This study examined the relationships among restaurant managers' attitudes, subjective norms, and perceived behavioral controls, using the Theory of Planned Behavior, that cause them to support or not support food safety training for their employees. The goal of this study was to investigate the facts that affect restaurant managers' willingness to support food safety training for their employees. Based on the results of the elicitation study, a pilot test focus group, and a pilot study, an 85 question instrument, that measured eight constructs and demographic information was developed. The instrument was administered via telephone, but response data was input using an online format. Data was entered electronically as it was collected. A total of 266 managers responded, but due to incomplete and missing data, 237 responses were usable. The final overall response rate was 17.9%. Results determined that overall intention to offer food safety training to employees was high. Restaurant managers had a positive attitude about food safety, placed importance on the beliefs of individuals they consider important, and felt they were in control about offering food safety training to their employees. Certified managers had more positive attitudes about offering food safety training and placed more emphasis on those individuals whom they considered to be important in their lives (subjective norms), but also perceived they had less control about offering food safety training to their employees. Most importantly, those managers who were certified had a higher intention to train employees than managers who did not have food safety certification. When comparing behavioral, normative, and control beliefs between chain and independent restaurant managers, only behavioral (specific attitudes) and normative beliefs (specific individuals whom they considered important) differed. In the multiple regression analysis exploring the prediction of behavior based on the respondents attitudes, subjective norms, and perceived behavioral controls, the model was significant (F=139.932, p [equal to or less than] .000) (Table 5.2). The significant independent variables in the model were the attitude mean composite score (Beta=-0.106, p [equal to or less than] .038) and the subjective mean composite score (Beta=0.727, p [equal to or less than] .000). Perception of control was not significant. Three multiple regression models were used to examine the relationships between the attitudes, subjective norms, and perceived behavioral controls as dependent variables and the factors for their indirect measures as independent variables. Of the three simple linear regression models, only two were significant. The regression of the behavioral belief factors on attitude composite score (Hypothesis 4) (F=16.714, p [equal to or less than] .000) and the regression of normative belief factors on the subjective norm composite score (F=11.896, p [equal to or less than] .000) were significant. The regression of control beliefs on perceived behavioral control showed no significance.
126

Outdoor Eating: Enjoying Nature the No-Waste Way

Hongu, Nobuko, Sparks, Elizabeth W., Franklin, Alexandra M. 04 1900 (has links)
4 pp. / Originally published 04/2011 / Finding foods to bring on a camping or hiking trip may seem challenging. Not only do they need to be nutritious, but they must also leave minimal waste so you can leave the environment just as you found it. Whole foods (such as fruits, nuts, and vegetables) tend to be better choices than processed foods (such as pre-packaged cereal bars, lunch meat) since they tend to be rich in nutrients and produce minimal waste. Finding reusable and recyclable ways to package your foods may also help cut down your impact on the environment. Revised 04/2016. Originally published 04/2011
127

Effect of food safety systems on the microbiological quality of beef

Tshabalala, Papiso Ariette 19 October 2011 (has links)
Contamination of meat with microorganisms during slaughter is inevitable. Hygiene management systems (HMSs) such as the Hygiene Assessment System (HAS) and Hazard Analysis Critical Control Point (HACCP) are used to prevent the contamination of beef with both spoilage and pathogenic microorganisms during slaughter. This study compared the effect of the HAS alone and a combination of HAS + HACCP on the microbiological quality of beef and investigated the survival of Escherichia coli O157:H7 co-cultured with different levels of Pseudomonas fluorescens and Lactobacillus plantarum on fresh beef. HAS alone and HAS combined with HACCP systems were each represented by two abattoirs. Sponge swab samples were collected from chilled beef carcasses for indicator organisms: Aerobic Plate Counts (APC), Enterobacteriaceae, Pseudomonas spp., and lactic acid bacteria. Swabs were also collected for pathogenic bacteria: E. coli O157:H7, Staphylococcus aureus and Salmonella spp. There was no significant difference between the microbiological quality of beef carcasses processed in the abattoirs with the HAS and that of beef carcasses processed in abattoirs with combined HAS + HACCP. E. coli O157:H7 was isolated from carcasses processed in an abattoir with the combined HAS + HACCP system. Moreover, although overall S. aureus counts at all abattoirs were comparable, a higher incidence (47% of carcasses) was obtained from an abattoir with combined HAS + HACCP. Salmonella spp. was not detected during the study. The microbiological quality of beef at HAS abattoirs is not significantly different to that of beef processed at HAS + HACCP abattoirs. The combined HAS + HACCP did not prevent contamination of beef carcasses with E. coli O157:H7 and S. aureus. Effective implementation of HAS can reduce contamination of beef with spoilage and pathogenic microorganisms. The effect of different levels of P. fluorescens (102 and 106 log10 cfu/ml) and L. plantarum (102 and 104 log10 cfu/ml) on the survival of E. coli O157:H7 on beef loins was investigated. Sterile beef loins inoculated with E. coli O157:H7 and P. fluorescens were aerobically stored for 7 days at 4°C, while those inoculated with E. coli O157:H7 and L. plantarum were vacuum-packaged and stored for 8 weeks at 4°C. APC, E. coli O157:H7 and either P. fluorescens or L. plantarum counts were determined at different storage intervals. For the aerobically packaged beef loins, E. coli O157:H7 was detected throughout the 7-day storage period regardless of the P. fluorescens level in the inoculum. For the vacuum packaged beef loins, similar inoculum levels of E. coli O157:H7 and L. plantarum allowed E. coli O157:H7 to survive until week 5 of storage, while a higher inoculum level of L. plantarum inhibited E. coli O157:H7 from week 3. Once fresh beef has been contaminated with E. coli O157:H7 the level of P. fluorescens in the background flora does not inhibit its survival and growth. However, under vacuum storage, the application of L. plantarum as a biopreservative inhibits the survival of E. coli O157:H7 on beef. Comprehensive strengthening of preventive strategies is required to eliminate contamination of beef carcasses with E. coli O157:H7. Bacterial contamination of carcasses during slaughter is inevitable. Effective implementation of HAS at abattoirs produces beef carcasses of microbiological quality comparable to that produced through the use of combined HAS and HACCP. While the level of P. fluorescens on beef does not inhibit the survival of E. coli O157:H7 on aerobically stored beef, the combination of L. plantarum, and low storage temperature inhibits the survival of this pathogen on beef under vacuum storage. / Thesis (PhD)--University of Pretoria, 2011. / Food Science / unrestricted
128

Aktuálne problémy skúšobníctva / Actual problems of metrology

Breyl, Martin January 2008 (has links)
Describe actual problems of metrology and system of food safety, official control and work of metrology laboratories.
129

Assessing Listeria monocytogenes contamination risk using predictive risk models and food safety culture management in retail environments

Tongyu Wu (8662944) 28 April 2020 (has links)
<p>Retail environments are critical transmission points for <i>Listeria monocytogenes</i> to humans. Past studies have shown <i>L. monocytogenes</i> contamination varies widely across retail environments. <i>L. monocytogenes</i> can transmit among environmental surfaces and subsequently from environment to food via cross-contamination. Modified SSOPs (sanitation standard operating procedures) have been shown to have limited impact on reducing <i>L. monocytogenes</i> prevalence in retail deli environments. Food safety culture and climate, such as beliefs, values, and hygiene behaviors, have been identified as factors impacting food safety performance and microbial outputs. Handwashing and its compliance are among the most prominent personal hygiene aspects subjected to investigation in the past decade, illustrating hygiene behavior as a risk factor and an important consideration to ensure food safety. Additionally, effective management and well-designed infrastructure, such as vertical and lateral communication, employees’ training, accountability, and equipment designed to prevent cross-contamination, have also been described as critical contributors to a sustainable food safety program. However, given such a deadly foodborne pathogen as <i>L. monocytogenes</i>, the correlation between food safety culture and its prevalence remains unknown. We hypothesized that there was a relationship among food safety culture management, infrastructure, and <i>L. monocytogenes</i> prevalence at retail. Our goal is to identify additional risk factors on <i>L. monocytogenes </i>control, develop feasible recommendations, and direct resources to enhance food safety. </p> <p>In the present dissertation, we developed and implemented a predictive risk model, along with employee- and management-implemented SSOPs, in 50 deli establishments across six U.S. states to evaluate and control <i>L. monocytogenes</i> contamination risk and prevalence (Chapter 2). The predictive risk model, based on logistic regression, uses five environmental sites to predict <i>L. monocytogenes</i> prevalence in the entire deli environment. It identified 13 high-risk stores, seven of which were confirmed during subsequent monthly sampling. We found that deep clean intervention reduced <i>L. monocytogenes </i>prevalence on non-food contact surfaces both immediately after the intervention and during follow-up, with marginal significance (α<sub>adj</sub>=0.0125). The employee- and management-implemented deep clean can control <i>L. monocytogenes</i> prevalence in retail delis; the predictive risk model, though conservative, will require further validations and can be useful for surveillance purposes. </p> <p>Complementary to the above study, we tackled the <i>L. monocytogenes</i> challenge via food safety culture and climate approach (Chapter 3). Concurrently to the monthly environmental sampling, we distributed food safety culture and climate survey to the 50 stores, with one manager and up to five associates from each establishment, over a 12-month period and overlapped with before, after, and follow-up deep clean. We found that stores with lower <i>L. monocytogenes</i> contamination risk had better food safety culture, including greater sense of commitment to food safety program (p<sub>adj</sub>=0.0317) and more complete training (p<sub>adj</sub>=0.0117). Deep clean improved managers’ (p<sub>adj</sub>=0.0243) and associates’ (p<sub>adj</sub>=0.0057) commitment to food safety. This study indicates that food safety culture and climate are crucial component in building a viable, sustainable food safety program. </p> <p>Another survey tool was used to evaluate infrastructure designs, management strategies, and sanitation practices in relation to <i>L. monocytogenes</i> control in retail produce environments (Chapter 4). We distributed the survey to 30 retail produce departments across seven U.S. states. Hand hygiene, minimizing cross-contamination, and maximizing equipment cleanability were the most prominent factors in <i>L. monocytogenes</i> control.</p>
130

Assessing local water quality in Saudi Arabia and its impact on food safety

Alsalah, Dhafer 12 1900 (has links)
Saudi Arabia produces a majority of its fruits and vegetables locally in small-scale production farms. These farms utilize groundwater as the main source of irrigation water. The water-regulating authorities in Saudi Arabia rely on traditional culturing methods to monitor coliforms as indicators of microbial contamination. These methods are time-consuming, do not address the sources of contamination, and do not permit assessment on the associated health risk. To address these knowledge gaps, the study investigates the sources of contamination in eight wells northeast of Mecca, Saudi Arabia. The study focuses on the potential impact on groundwater quality due to a nearby chicken farm and urban runoffs from human residential areas. Besides performing conventional methods to determine nutrient content and to enumerate coliforms, quantitative PCR using four host-associated primer sets were used to distinguish microbial contamination from humans and livestock. High-throughput sequencing was also performed to determine the relative abundance of several genera associated with opportunistic pathogens. Bacterial isolates were cultivated from the vegetable samples harvested from these farms, and were characterized for their phylogenetic identities. Lastly, the study collates the information to perform quantitative microbial risk assessment due to ingesting antibiotic-resistant Listeria monocytogenes, Pseudomonas aeruginosa and Enterococcus faecalis in these vegetable samples.

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