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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.
21

The experience of formula feeding infants among women with mental health challenges

Humphries, Joan M. 26 May 2010 (has links)
Women in the perinatal period who suffer from mental health challenge (and specifically mood disorders) have a number of special considerations to which they must attend. Issues around psychotropic medication, hormonal fluctuations and/or sleep hygiene, for example, may lead women to a decision to feed their infants with formula. In this hermeneutic study, the experiences of six women are studied. The women are registered with Perinatal Mental Health Program at Vancouver Island Health Authority, and are feeding their infants with formula. Evidence- based-practice guidelines are explored in the context of mental health challenge. A dilemma has been exposed around the perceived need expressed by participants for ‘permission’ to discontinue or not initiate breastfeeding. The potential for further understanding looms with regard to the relationship between breastfeeding challenge and the onset of a mood disorder, including the speculation that breastfeeding difficulties may belong on the list of risk factors for post partum depression.
22

Addressing Multinational Corporations’ Aggressive Marketing of Commercial Formula in Indonesia and the Cessation of Breastfeeding Through the Design and Evaluation of a Counter-marketing Continuing Education Module

Hidayana, Irma January 2019 (has links)
The purpose of this study was to address the aggressive marketing of commercial formula and breastfeeding cessation in Indonesia using an evaluation of a counter-marketing continuing education module. Using a convenience sample (N = 99) of breastfeeding educators and/or counselors, paired t-tests showed a significant increase in participants’ knowledge about counter-marketing after they participated in the training. Findings also showed significant increases post-training for stage of changes, self-efficacy, knowledge, and motivation to perform four key talking behaviors: i.e., involving talking to new and pregnant mothers about corporations’ inappropriate and aggressive marketing of formula, and the risks of becoming dependent on expensive formula and losing the ability to produce their own breast milk. These findings suggested that exposure to the counter-marketing continuing education training served as a brief intervention associated with significant improvements in level of knowledge about counter-marketing among participants and in stage of change self-efficacy, knowledge, and motivation for performing key behaviors of interest. Backward-stepwise regression revealed that higher level of motivation for taking an active role in the proposed campaign (i.e., A Campaign to Expose the Truth about Becoming Dependent on Commercial Formula and Breastfeeding Cessation) was significantly predicted by: (1) higher pre-training self-efficacy for talking to expectant and new mothers about the reasons to breastfeed their infant (β = .327, SEB = .118, p = .007); (2) lower pre-training knowledge for talking to expectant and new mothers about corporations’ inappropriate and aggressive marketing of commercial infant formula (β = -.270, SEB = .092, p = .004); and, (3) higher level of knowledge for taking an active role in the proposed campaign (β = .392, SEB = .083, p = .000). Participants rated the training as very good (74.7%, n = 74). Qualitative data showed that the training provided new knowledge and a new approach in addressing aggressive formula marketing by corporations. Further, participants found that the training has made them more confident and motivated to work with mothers and the community to advocate and educate about negative impacts from commercial formula.
23

Buying behaviour for newborn baby milk powder within the context of China's one-child policy

Guo, Weirong January 2008 (has links)
Submitted in fulfilment of the requirements for the Degree of Master of Technology: Marketing, Durban University of Technology, 2008. / The purpose of this study was to evaluate Chinese parents' buying behaviour towards baby milk powder in the context of China's One-Child policy. The study examined the Chinese culture, social trends, the influence of product attributes among urban Chinese parents and parents' product knowledge of baby milk powder. This study is an exploratory study. A questionnaire was used to collect the data from 400 respondents at Shangdong University, China. There are 312 respondents' questionnaires used to analyse the results. The results were discovered through the use of four research objectives. Firstly, the results reflect that family and friends do have an influence on buying decisions on baby milk powder. There parents rely more on word-of-mouth communication and shop assistants play a negative role in parents' buying decision. Secondly, mothers need to opt for baby milk powder for their babies due to the flood of women into the job market and incomes from dual earners. Thirdly, parents perceive high price with good quality; the preferred brand by the parents have a significant impact on their brand loyalty and parents generally hold positive views of foreign-made baby milk powder. Fourthly, parents have a high level of subjective and objective knowledge of baby milk powder. This study was limited to the sample size and the geographic area. Consequently, results of this study can not be regarded as representative of the entire Chinese population. The results may help marketers develop more effective marketing programmes to affect consumers' buying decision. In addition, this study is one of a few studies that apply the theory of buying behaviour in the context of China's One-Child policy in the marketing field. / M
24

Desenvolvimento de métodos analíticos para avaliação da presença de elementos essenciais e potencialmente tóxicos em fórmulas infantis

Gamela, Raimundo Rafael January 2017 (has links)
O consumo de fórmulas infantis no Brasil, utilizadas como substituto do leite materno, tem aumentado nos últimos anos de forma significativa. Tal fato é uma preocupação para os órgãos de saúde pois, o aleitamento materno exclusivo até no mínimo 6 meses, deixou de fazer parte de nutrição da maioria dos lactentes. Os produtos utilizados como substituto do leite materno contêm quantidades suficientes de vitaminas e nutrientes que ajudam no desenvolvimento normal do organismo dos lactentes. Entretanto, além de elementos essenciais, podem conter elementos potencialmente tóxicos presentes na matéria prima ou oriundos das etapas de processamento e armazenamento das mesmas. No presente trabalho foram desenvolvidos métodos analítico para determinar a presença de elementos potencialmente tóxicos (As, Cd, Pb e Tl) e essenciais (Cu e Mn) em fórmulas infantis, utilizando espectrometria de absorção atômica de alta resolução com fonte contínua e forno de grafite e análise direta de sólidos. As amostras utilizadas neste trabalho foram obtidas nos mercados da cidade de Porto Alegre, RS, Brasil, todas na forma sólida (pó) com diferentes composições e matéria prima (arroz, aveia, soja e leite). As curvas de calibração foram realizadas com soluções padrão aquosas e os métodos otimizados foram aplicados nas amostras em estudo. Em todas as amostras os elementos As, Cd, Pb e Tl apresentaram valores de concentração abaixo do limite de detecção. Das seis amostras analisadas, três apresentaram valores de concentração de Cu abaixo dos parâmetros mínimos estabelecidos pela legislação brasileira, enquanto que para o Mn todas amostras apresentaram valores de concentração dentro dos parâmetros mínimos da legislação brasileira. Os métodos desenvolvidos foram simples, exatos e precisos, podendo ser utilizados para análise de rotina. / The consumption of infant formula in Brazil, as a replacement of breast milk, has lately increased significantly. It is a major concern for health agencies because the exclusive breastfeeding up to at least 6 months is no longer part of most infants. The products used as a substitute of the breast milk contain sufficient amounts of vitamins and nutrients, which helps in the normal development of the infants. However, besides the essential elements, it may contain potentially toxic elements present in raw material or from of the processing and storage stages of the same. In the present work the presence of the essential (Cu e Mn) and potentially toxic elements (As, Cd, Pb e Tl) in infant formulas were evaluated. For this, analytical methods were developed for the determination of As, Cd, Cu, Mn, Pb and Tl using high-resolution continnum source graphite furnace atomic absorption spectrometry and direct solid sampling analysis in infant formulas. The samples were acquired in Porto Alegre’s market, RS, Brazil, all in powder form with different compositions and raw materials (rice, oats, soy and bovine milk). The calibration curves were performed with aqueous standard solutions and the optimized methods were applied in the study samples. In all samples, the concentration values of As, Pb, Cd and Tl were below of the limit of detection. For the analyzed samples, three of them present the concentration values of Cu lower than the minimum parameters established by Brazilian legislation, while for Mn, all samples present the concentration values within the minimum parameters of Brazilian legislation. The developed methods for the determination of these elements in infant formulas were simple, exacts and precise, and can be applicated for the routine analysis.
25

âFluorose dentÃria em crianÃas de seis a oito anos residentes na Ãrea de abrangÃncia de uma unidade bÃsica de saÃde, Fortaleza-Ce: estudo de caso-controleâ / Dental fluorosis in 6-8-year-old children living in the abrangency area of a primary health center in Fortaleza-CE: case-control study

Ana Karine Macedo Teixeira 29 June 2009 (has links)
O aumento da prevalÃncia de fluorose dentÃria à observado tanto em comunidades com Ãgua fluoretada como em Ãreas nÃo fluoretadas, sugerindo assim a ingestÃo de flÃor por outras fontes alÃm da Ãgua de abastecimento pÃblico. O objetivo deste trabalho foi pesquisar a fluorose dentÃria em crianÃas de seis à oito anos no MunicÃpio de Fortaleza-CE e investigar possÃveis fatores de risco ou de proteÃÃo para a fluorose, alÃm de sua relaÃÃo com fatores socioeconÃmicos. Tratou-se de um estudo do tipo caso-controle, desenvolvido no Centro de SaÃde da FamÃlia (CSF) Terezinha Parente. A amostra constou-se de 57 crianÃas sem fluorose (grupo-controle) e 67 crianÃas com fluorose (grupo de casos), onde foi utilizado o Ãndice de Dean para a mediÃÃo da fluorose e definiÃÃo de casos e controles. Os dados foram obtidos atravÃs de entrevistas, com base em um roteiro estruturado com os pais das crianÃas. A anÃlise dos dados foi realizada no programa Epi-Info Windows, onde se utilizou o teste exato de Fisher para verificar a associaÃÃo entre as variÃveis, considerando significativo quando o valor de p<0,05. Calculou-se ainda o odds ratio com intervalo de confianÃa de 95%. Foi observada uma associaÃÃo estatisticamente significante entre a variÃvel condiÃÃo de moradia e fluorose dentÃria (p=0,024 e OR=3,82), enquanto para os outros fatores socioeconÃmicos nÃo foi observada nenhuma associaÃÃo. Com relaÃÃo à fonte de Ãgua para consumo, os dentifrÃcios fluoretados e suplementos de flÃor, nÃo se verificou nenhuma associaÃÃo significante com a presenÃa de fluorose. Observou-se, porÃm, que as crianÃas que iniciaram o consumo de leite em pà reconstituÃdo com Ãgua antes dos dois anos de idade apresentaram uma chance de 4,53 vezes maior de apresentar fluorose (p=0,036). E as crianÃas que nÃo mamaram apresentaram uma chance de 6,66 vezes maior de possuir fluorose dentÃria do que as que mamaram por mais de seis meses (p=0,007). A amamentaÃÃo se configurou como um fator de proteÃÃo para a fluorose dentÃria, enquanto a ingestÃo de leite em pà reconstituÃdo com Ãgua antes dos dois anos se apresentou como um fator de risco. à de fundamental importÃncia o estÃmulo à amamentaÃÃo por parte dos profissionais de saÃde, para garantir nÃo sà uma melhor saÃde geral das crianÃas, mas tambÃm uma melhor saÃde bucal. / The increase of dental fluorosis has been observed in fluoridated and non-fluoridated locations, suggesting the fluoride intake by others sources besides water fluoridated. The aim of this study was to investigate the dental fluorosis in children aged 6 to 8 in Fortaleza, CearÃ, to identify risk and protection factors for dental fluorosis and to verify the possible associated of fluorosis with socioeconomic status. It was a case-control study realized at the health center Terezinha Parente. A total of 57 controls and 67 cases were examined by the Dean index. Data was obtained by interviewing the parents of the children, based on a structured questionnaire. Analyses of the data occurred at the Epi-Info Windows program by the Fisher test with p<0,05 and the odds ratio was calculated, with confidence interval of 95%. Statistically associated between dental fluorosis and the variable condition of live was observed (p=0,024 e OR=3,82), while no association was observed by the others socioeconomic factors. Fluoride intake by children from water, dentifrice and fluoride supplement demonstrated no significant results. But, the children who consumed powdered milk reconstituted with water before 2 years old presented 4,53 more chance to have dental fluorosis (p=0,036). And the children who have not breastfeeding presented 6,66 more chance to have fluorosis than that who breastfeeding for more than 6 mouths (p=0,007). Breastfeeding showed to be a protections factor to dental fluorosis and the consume of powdered milk reconstituted with water before 2 years old demonstrated to be risk factor in this population. Itâs important to health workers recommend breastfeeding to guarantee the oral health of children.
26

Antimicrobial effect of yogurt lactic acid bacteria and muscadine products on Enterobacter sakazakii

Weng, Wei-Lien, January 2008 (has links)
Thesis (Ph.D.)--Mississippi State University. Department of Food Science, Nutrition and Health Promotion. / Title from title screen. Includes bibliographical references.
27

Detection of Enterobacter sakazakii in South African food products

Kemp, Francisca 12 1900 (has links)
Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2005. / It is estimated by the World Health Organisation (WHO) that thousands of millions of cases of foodborne diseases occur world–wide every year. Enterobacter sakazakii is a member of the family Enterobacteriaceae and has been identified as an occasional contaminant of powdered infant formula milk (IFM). Enterobacter sakazakii is an opportunistic emerging pathogen and has the ability to cause a severe form of neonatal meningitis. This organism was referred to as “yellow pigmented Enterobacter cloacae” until 1980 after which it was renamed as E. sakazakii. The current method for the detection of E. sakazakii is very time consuming and includes pre–enrichment, enrichment in Enterobacteriaceae enrichment broth, subsequent plating on violet red bile glucose agar and subculturing on tryptone soy agar. In this study a polymerase chain reaction (PCR) method was developed for the identification of the presence of E. sakazakii in infant food products. A part of the 16S ribosomal RNA (rRNA) gene from E. sakazakii was amplified using the primer pair Esak2 and Esak3. An internal amplification control (IAC) was constructed as part of the PCR detection method. The 850 base pair (bp) E. sakazakii PCR product was digested with AluI and the two fragments containing the primer binding sites were ligated, resulting in a 240 bp IAC. During this study a positive band for both the target DNA (850 bp) and the IAC (240 bp) was simultaneously observed when the IAC was added to the PCR mixture at a concentration of 0.72 pg.ml-1. Four of 22 South African food products tested positive for the presence of E. sakazakii, using both the PCR and recommended culturing methods. The PCR method was used successfully for the detection of E. sakazakii within three days and thus provides a possible alternative and improvement on the recommended current culturing methods. Other microorganisms present in the products tested included Escherichia coli, Klebsiella pneumoniae, Raoultella terrigena (“Klebsiella terrigena”) and Chryseomonas luteola. Since E. sakazakii is usually present in low numbers in food products, it is possible that these few cells are unevenly distributed in the products, making it important to take multiple samples when evaluating IFM and thereby ensuring that even low numbers of this pathogen are detected.
28

Desenvolvimento de métodos analíticos para avaliação da presença de elementos essenciais e potencialmente tóxicos em fórmulas infantis

Gamela, Raimundo Rafael January 2017 (has links)
O consumo de fórmulas infantis no Brasil, utilizadas como substituto do leite materno, tem aumentado nos últimos anos de forma significativa. Tal fato é uma preocupação para os órgãos de saúde pois, o aleitamento materno exclusivo até no mínimo 6 meses, deixou de fazer parte de nutrição da maioria dos lactentes. Os produtos utilizados como substituto do leite materno contêm quantidades suficientes de vitaminas e nutrientes que ajudam no desenvolvimento normal do organismo dos lactentes. Entretanto, além de elementos essenciais, podem conter elementos potencialmente tóxicos presentes na matéria prima ou oriundos das etapas de processamento e armazenamento das mesmas. No presente trabalho foram desenvolvidos métodos analítico para determinar a presença de elementos potencialmente tóxicos (As, Cd, Pb e Tl) e essenciais (Cu e Mn) em fórmulas infantis, utilizando espectrometria de absorção atômica de alta resolução com fonte contínua e forno de grafite e análise direta de sólidos. As amostras utilizadas neste trabalho foram obtidas nos mercados da cidade de Porto Alegre, RS, Brasil, todas na forma sólida (pó) com diferentes composições e matéria prima (arroz, aveia, soja e leite). As curvas de calibração foram realizadas com soluções padrão aquosas e os métodos otimizados foram aplicados nas amostras em estudo. Em todas as amostras os elementos As, Cd, Pb e Tl apresentaram valores de concentração abaixo do limite de detecção. Das seis amostras analisadas, três apresentaram valores de concentração de Cu abaixo dos parâmetros mínimos estabelecidos pela legislação brasileira, enquanto que para o Mn todas amostras apresentaram valores de concentração dentro dos parâmetros mínimos da legislação brasileira. Os métodos desenvolvidos foram simples, exatos e precisos, podendo ser utilizados para análise de rotina. / The consumption of infant formula in Brazil, as a replacement of breast milk, has lately increased significantly. It is a major concern for health agencies because the exclusive breastfeeding up to at least 6 months is no longer part of most infants. The products used as a substitute of the breast milk contain sufficient amounts of vitamins and nutrients, which helps in the normal development of the infants. However, besides the essential elements, it may contain potentially toxic elements present in raw material or from of the processing and storage stages of the same. In the present work the presence of the essential (Cu e Mn) and potentially toxic elements (As, Cd, Pb e Tl) in infant formulas were evaluated. For this, analytical methods were developed for the determination of As, Cd, Cu, Mn, Pb and Tl using high-resolution continnum source graphite furnace atomic absorption spectrometry and direct solid sampling analysis in infant formulas. The samples were acquired in Porto Alegre’s market, RS, Brazil, all in powder form with different compositions and raw materials (rice, oats, soy and bovine milk). The calibration curves were performed with aqueous standard solutions and the optimized methods were applied in the study samples. In all samples, the concentration values of As, Pb, Cd and Tl were below of the limit of detection. For the analyzed samples, three of them present the concentration values of Cu lower than the minimum parameters established by Brazilian legislation, while for Mn, all samples present the concentration values within the minimum parameters of Brazilian legislation. The developed methods for the determination of these elements in infant formulas were simple, exacts and precise, and can be applicated for the routine analysis.
29

Desenvolvimento de métodos analíticos para avaliação da presença de elementos essenciais e potencialmente tóxicos em fórmulas infantis

Gamela, Raimundo Rafael January 2017 (has links)
O consumo de fórmulas infantis no Brasil, utilizadas como substituto do leite materno, tem aumentado nos últimos anos de forma significativa. Tal fato é uma preocupação para os órgãos de saúde pois, o aleitamento materno exclusivo até no mínimo 6 meses, deixou de fazer parte de nutrição da maioria dos lactentes. Os produtos utilizados como substituto do leite materno contêm quantidades suficientes de vitaminas e nutrientes que ajudam no desenvolvimento normal do organismo dos lactentes. Entretanto, além de elementos essenciais, podem conter elementos potencialmente tóxicos presentes na matéria prima ou oriundos das etapas de processamento e armazenamento das mesmas. No presente trabalho foram desenvolvidos métodos analítico para determinar a presença de elementos potencialmente tóxicos (As, Cd, Pb e Tl) e essenciais (Cu e Mn) em fórmulas infantis, utilizando espectrometria de absorção atômica de alta resolução com fonte contínua e forno de grafite e análise direta de sólidos. As amostras utilizadas neste trabalho foram obtidas nos mercados da cidade de Porto Alegre, RS, Brasil, todas na forma sólida (pó) com diferentes composições e matéria prima (arroz, aveia, soja e leite). As curvas de calibração foram realizadas com soluções padrão aquosas e os métodos otimizados foram aplicados nas amostras em estudo. Em todas as amostras os elementos As, Cd, Pb e Tl apresentaram valores de concentração abaixo do limite de detecção. Das seis amostras analisadas, três apresentaram valores de concentração de Cu abaixo dos parâmetros mínimos estabelecidos pela legislação brasileira, enquanto que para o Mn todas amostras apresentaram valores de concentração dentro dos parâmetros mínimos da legislação brasileira. Os métodos desenvolvidos foram simples, exatos e precisos, podendo ser utilizados para análise de rotina. / The consumption of infant formula in Brazil, as a replacement of breast milk, has lately increased significantly. It is a major concern for health agencies because the exclusive breastfeeding up to at least 6 months is no longer part of most infants. The products used as a substitute of the breast milk contain sufficient amounts of vitamins and nutrients, which helps in the normal development of the infants. However, besides the essential elements, it may contain potentially toxic elements present in raw material or from of the processing and storage stages of the same. In the present work the presence of the essential (Cu e Mn) and potentially toxic elements (As, Cd, Pb e Tl) in infant formulas were evaluated. For this, analytical methods were developed for the determination of As, Cd, Cu, Mn, Pb and Tl using high-resolution continnum source graphite furnace atomic absorption spectrometry and direct solid sampling analysis in infant formulas. The samples were acquired in Porto Alegre’s market, RS, Brazil, all in powder form with different compositions and raw materials (rice, oats, soy and bovine milk). The calibration curves were performed with aqueous standard solutions and the optimized methods were applied in the study samples. In all samples, the concentration values of As, Pb, Cd and Tl were below of the limit of detection. For the analyzed samples, three of them present the concentration values of Cu lower than the minimum parameters established by Brazilian legislation, while for Mn, all samples present the concentration values within the minimum parameters of Brazilian legislation. The developed methods for the determination of these elements in infant formulas were simple, exacts and precise, and can be applicated for the routine analysis.
30

Detection, identification and live/dead differentiation of the emerging pathogen Enterobacter sakazakii from infant formula milk and the processing environment

Cawthorn, Donna-Maree 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: The World Health Organisation (WHO) estimates that at least 75% of infants receive infant formula milk (IFM) either entirely or in conjunction with breast milk during the first four months after birth. The presence of the emerging pathogen Enterobacter sakazakii in IFM has been associated with rare but fatal cases of neonatal infections and deaths. There is thus a need for accurate methods for the rapid detection of E. sakazakii in foods. At present, the methods used to detect and identify this micro-organism are inadequate, controversial and contradictory. The aim of this study was to determine the most suitable method for E. sakazakii detection after evaluation of the currently available methods. A further aim was to optimise a polymerase chain reaction (PCR) method for the detection of only viable E. sakazakii cells utilising the DNA-intercalating dyes ethidium monoazide (EMA) and propidium monoazide (PMA). The Food and Drug Administration (FDA) method for E. sakazakii detection was utilised to select 50 isolates from IFM and 14 from the environment, regardless of colony appearance. These isolates were identified by sequencing a 1.5 kilobase (kb) fragment of the 16S ribosomal DNA (rDNA) and by using the National Centre for Biotechnological Information (NCBI) database to confirm the closet known relatives. Seven of the 50 (14%) IFM isolates and six of the 14 (43%) environmental isolates were identified as E. sakazakii. The methods that were evaluated for accuracy in detecting and identifying these E. sakazakii isolates included yellow pigment production on tryptone soy agar (TSA), chromogenic Druggan-Forsythe-Iversen (DFI) and Enterobacter sakazakii (ES) agars and PCR using six different species-specific primer pairs described in the literature. The suitability of the FDA method was lowered by the low sensitivity, specificity and accuracy (87%, 71% and 74%, respectively) of using yellow pigment production for E. sakazakii identification. DFI and ES agars were shown to be sensitive, specific and accurate (100%, 98% and 98%, respectively) for the detection of E. sakazakii. The specificity of the PCR amplifications was found to vary between 8% and 92%, with Esakf and Esakr being the most accurate of the primer pairs evaluated. The current FDA method for E. sakazakii detection requires revision in the light of the availability of more sensitive, specific and accurate detection methods. Based on the results obtained in this study, a new method is proposed for the detection of E. sakazakii in food and environmental samples. This proposed method replaces the culturing steps on violet red bile glucose agar (VRBGA) and TSA with culturing on chromogenic DFI or ES agar. For identification and confirmation of presumptive E. sakazakii isolates, the oxidase test, yellow pigment production and API biochemical profiling is replaced by DNA sequencing and/or species-specific PCR with the most accurate primer pair (Esakf and Esakr). The amendments to the current FDA method will reduce the time to detect E. sakazakii from approximately 7 days to 4 days and should prove to be more sensitive, specific and accurate for E. sakazakii detection. In this study, a novel PCR-based method was developed which was shown to be capable of discriminating between viable and dead E. sakazakii cells. This was achieved utilising the irreversible binding of bacterial DNA to photo-activated PMA or EMA in order to prevent PCR amplification from the dead cells. At concentrations of 50 and 100 μg.ml-1, PMA completely inhibited PCR amplification from dead cells, while causing no significant inhibition of the PCR amplification from viable cells. EMA was equally effective in preventing PCR amplification from dead cells, however, it also inhibited PCR amplification from viable cells. PMA-PCR in particular, will be useful for assessing the efficacy of processing techniques, as well as for monitoring the resistance, survival strategies and stress responses of E. sakazakii. This will be an important step in the efforts to eliminate E. sakazakii from food and food production environments. / AFRIKAANSE OPSOMMING: Die Wêreld Gesondheidsorganisasie (WGO) beraam dat ten minste 75% van alle babas net baba formule melk (BFM) of BFM in kombinasie met moedersmelk in die eerste vier maande na geboorte kry. Die teenwoordigheid van die voortkomende patogeen Enterobacter sakazakii in BFM is al geassosieer met skaars maar noodlottige gevalle van neonatale infeksies en sterftes. Akkurate metodes word dus benodig vir die vinnige deteksie van E. sakazakii in voedsel. Die metodes wat huidiglik gebruik word vir die deteksie en identifikasie van hierdie mikroörganisme is onvoldoende, kontroversieël en teenstrydig. Die doel van hierdie studie was om die beste metode vir die deteksie van E. sakazakii te bepaal, na 'n evaluasie van die metodes wat huidiglik beskikbaar is. 'n Verdere doel was om 'n polimerase ketting reaksie (PKR) metode vir die deteksie van slegs lewensvatbare E. sakazakii selle te optimiseer deur gebruik te maak van die DNSbindende kleurstowwe, etidium mono-asied (EMA) en propidium mono-asied (PMA). Die Voedsel en Medisyne Administrasie (VMA) se metode vir E. sakazakii deteksie is gebruik om, ongeag van die kolonie kleur, 50 isolate vanuit BFM en 14 isolate vanuit die omgewing te kies. Hierdie isolate is geïdentifiseer deur die DNS volgorde van 'n 1.5 kilo-basis (kb) fragment van die 16S ribosomale DNS (rDNS) te bepaal en die Nationale Sentrum vir Biotegnologiese Informasie (NSBI) databasis te gebruik om die mees verwante spesie te bevestig. Sewe van die 50 (14%) BFM isolate en ses van die 14 (43%) omgewings isolate is geïdentifiseer as E. sakazakii. Die metodes wat geëvalueer is in terme van akkuraatheid vir deteksie en identifikasie van hierdie E. sakazakii isolate het PKR met ses verskillende spesie-spesifieke peiler pare soos beskryf in die literatuur, geel-pigment produksie op triptoon soja agar (TSA) en chromogeniese Druggan-Forsythe-Iversen (DFI) en Enterobacter sakazakii (ES) agars ingesluit. Die geskiktheid van die VMA metode is verlaag deur die lae sensitiwiteit, spesifisiteit en akkuraatheid (87%, 71% en 74% onderskeidelik) van geel pigment produksie vir E. sakazakii identifikasie. Chromogeniese DFI en ES agars was sensitief, spesifiek en akkuraat (100%, 98% en 98% onderskeidelik) vir die identifikasie van E. sakazakii. Die spesifisiteit van die PKR produkte het gewissel tussen 8% en 92%, en Esakf en Esakr is as die akkuraatste geëvalueerde peiler paar geidentifiseer. Die huidige VMA metode vir E. sakazakii deteksie vereis hersiening aangesien meer sensitiewe, spesifieke en akkurate deteksiemetodes voortdurend beskikbaar word. 'n Nuwe metode, gebaseer op die resultate van hierdie studie, word voorgestel vir die deteksie van E. sakazakii in voedsel- en omgewingsmonsters. Die voorgestelde metode vervang die kwekingsstap op violet rooi gal glukose agar (VRGGA) en TSA deur kweking op chromogeniese DFI of ES agars. Verder word die oksidase toets, geel pigment produksie en API biochemiese profiele van vermoeidelike E. sakazakii isolate vervang deur DNS volgorde bepaling en/of spesie-spesifieke PKR met die mees spesifieke peiler paar (Esakf and Esakf) vir die identifikasie en bevestiging van E. sakazakii. Die voorgestelde wysigings van die VMA metode sal die tydsduur van E. sakazakii identifikasie van 7 dae na 4 dae verminder, en behoort ook meer sensitief, spesifiek en akkuraat te wees vir die deteksie van E. sakazakii. 'n Nuwe PKR-gebaseerde metode wat tussen lewensvatbare en dooie E. sakazakii selle kan onderskei is in hierdie studie ontwikkel. Dit is bereik deur die onomkeerbare binding van bakteriële DNS aan lig-geaktiveerde EMA of PMA om die PKR amplifisering van dooie selle te voorkom. Konsentrasies van 50 en 100 μg.ml-1 PMA het PKR amplifikasie heeltemal geïnhibeer, terwyl geen inhibisie van lewensvatbare selle bespeur kon word nie. EMA was ook suksesvol in die voorkoming van die PKR amplifikasie van dooie selle, alhoewel daar ook 'n mate van DNS inhibisie was tydens die amplifikasie van lewensvatbare selle. PMA-PKR kan ook van nut wees vir die assessering van die doeltreffendheid van prosesseringstegnieke, en ook vir die waarneming van die weerstandigheid, oorlewingsstrategieë en stresresponse van E. sakazakii. Dit sal 'n belangrike stap wees in pogings om E. sakazakii van voedsel en voedsel produksieomgewings te elimineer.

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