Thesis (MScVoedselwet)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Milk has been identified as having the potential of being a carrier of human pathogens, and it is thus essential to eliminate or reduce the likelihood of milk borne contamination. This problem of milk contamination is generally solved by the process of pasteurisation which is achieved by heating the "raw" material for a sufficient period of time to destroy any pathogenic and spoilage bacteria which may be present at a temperature of below 100°C. Presently, there are two basic methods of pasteurisation in use in the dairy industry, the LTLT and the HTST methods, where the applied heat treatment is considered sufficient to ensure public safety and adequate keeping quality. In addition to these, there is another method, the "pot" pasteurisation, to be found in Southern Africa that was designed to eliminate potential pathogenic and spoilage bacteria present in raw milk. As far as it is known no thermal studies have been done on the "pot" pasteurisation method. The objectives of this study were to determine the impact of different milk pasteurisation temperature and time combinations on the survival of selected microbes. The accuracy of the "pot" pasteurisation method and how it differs from the other pasteurisation methods was also determined using the same selected microbes. The six selected microbes were thermally inactivated by using the LTLT, HTST and the "pot" pasteurisation methods at low and high inoculum levels of 104 and 106 cfu.ml-1. The thermal death curves were constructed for each selected species. The selected microbes included the strains Bacillus cereus (S4), Chryseobacterium meningosepticum (S5), Pseudomonas putida (S6), Acinetobacter baumannii (C3), Escherichia coli (58) and Candida lipolytica (G1). Survivors were enumerated after heating for 0, 5, 10, 15, 20, 25, 30, 35 and 40 min for both the LTLT and HTST pasteurisation methods and after heating for 0, 10, 20 and 30 min for the "pot" pasteurisation method. The results from this study showed that with the exception of the B. cereus strain, the other selected microbes at both high and low concentration levels did not survive the LTLT or the HTST pasteurisation methods. It was found that for all the organisms used in this study, there was a rapid initial death rate just before the required pasteurisation temperatures of 63°, 72° and 90°C were reached, during the "come-up" period. In contrast, the results from the "pot" pasteuriser showed that theB. cereus (S4), Chr. meningosepticum (S5), P. putida (S6), A. baumannii (C3) and E. coli (58) strains survived the pasteurisation conditions applied. From these results it was thus concluded that the "pot" pasteuriser under the conditions evaluated in this study, did not pasteurise effectively. Therefore, it is recommended that the manufacturer improves the heating quality of the "pot" pasteuriser. As it was found that only the B. cereus (S4) strain survived all the different pasteurisation methods, future research needs to be done to determine at which temperature this heat resistant bacterial strain will be destroyed. This is very important because there is a need to destroy all the spoilage microorganisms that can lead to the deterioration of food products. / AFRIKAANSE OPSOMMING: Melk is 'n potensiële draer van mikrobes wat patogenies is vir die mens. Dit is dus essensiëel om die besmetting van melk te verlaag of te elimineer. Die probleem van melkbesmetting word opgelos deur die proses van pasteurisasie. Die proses word toegepas deur verhitting van die rou material vir 'n voldoende periode om patogeniese en bederf organismes te vernietig. Temperature onder 100°C word gebruik. In die suiwelbedryf word twee basiese metodes gebruik: die LTLT (lae temperatuur, lang tyd) metode en die HTKT (hoë temperatuur, kort tyd) metode. Albei hittebehandelings is voldoende om publieke veiligheid en 'n genoegsame rakleeftyd te verseker. 'n Derde metode, "pot" pasteurisasie, word in Suidelike Afrika gebruik. Die metode is ontwikkel om potensiële patogene en bederf organismes in rou melk te elimineer. Die probleem is dat daar geen navorsing op die temperatuur eienskappe van die “pot" metode gedoen is nie. Die doelwitte van hierdie navorsing was om die effek van verskillende temperatuur:tyd kombinasies op die oorlewing van sekere mikrobes te bepaal. Die akkuraatheid van die "pot" metode en die manier hoe dit van ander metodes verskil, is ook in ag geneem. Die navorsing is ten alle tye gebaseer op die geselekteerde mikroorganismes. Die ses geselekteerde spesies van mikrobes is vernietig deur middel van die LTLT, HTKT en "pot" pasteurisasie metodes. Die mikrobes is geïnaktiveer teen lae en hoë inokulums van 104 en 106 kve.ml-1. Terminale dodings kurwes is opgestel vir elke geselekteerde spesie. Die mikrobes van belang is Bacillus cereus (S4), Chryseobacterium meningosepticum (S5), Pseudomonas putida (S6), Acinetobacter baumannii (C3), Escherichia coli (58) en Candida lipolytica (G1). Die oorlewende mikroorganismes is na hitte behandelings van 0, 5, 10, 15, 20, 25, 30, 35 en 40 minute vir beide die LTLT en die HTKT pasteurisasie metodes en na hitte behandelings van 0, 10, 20, en 30 minute vir die "pot" pasteurisasie metode getel. Die resultate van die navorsing dui aan dat, behalwe vir B. cereus, die geselekteerde mikrobes teen beide lae en hoë konsentrasies nie die LTLT en die HTKT metodes oorleef het nie. Daar is gevind dat, vir al die organismes, vinnige aanvanklike dodingstempos teenwoordig was net voor die noodsaaklike pasteurisasie temperatuur van 63°, 72° en 90°C bereik is, gedurende die "come-up" periode. Inteenstelling hiermee het die resultate van die "pot" metode bewys dat B.cereus (S4), Chr. meningosepticum (S5), P. putida (S6), A. baumannii (C3) en E. coli (58) stamme die pasteurisasie toestande oorleef het. Uit die resultate is ’n gevolgtrekking gemaak dat die "pot" pasteurisasie metode nie effektief was nie. Daar word dus aanbeveel dat die vervaardiger die verhittings-kwaliteit van die "pot" pasteurisasie apparaat verbeter. Aangesien net die B. cereus (S4) stam al drie pasteurisasie metodes oorleef het, moet toekomstige navorsing gedoen word om die vernietigings temperatuur van dié hittebestande stam te bepaal. Die navorsing is van belang weens die behoeftes om alle bederf mikroorganismes wat tot die agteruitgang van voedsel produkte kan lei, te vernietig.

Orientador: José Moacir Marin / Banca: Everlon Cid Rigobelo / Banca: Simone Barone Salgado Marques / Resumo: A mastite representa um dos mais sérios problemas existentes nas fazendas de leite. Os objetivos deste estudo foram identificar leveduras envolvidas nos casos de mastite bovina; avaliar a sensibilidade in vitro de cepas de Candida spp. frente a quatro desinfetantes utilizados no pré e pós-dipping e avaliar a resistência destas leveduras frente à pasteurização e fervura. Cinquenta e cinco amostras (12,8%) foram positivas para o gênero Candida. As espécies mais isoladas foram C. krusei (34,6%), C. parapsilosis (25,4%), C. tropicalis (18,2%) e C. albicans (12,8%). As drogas utilizadas foram clorexidina (2,0%), iodo (0,8%), iodo glicerinado (0,8%) e hipoclorito de sódio (1,0%) em 4 intervalos específicos de tratamento (15″, 30″, 60″ e 300″). Cem por cento das cepas de Candida foram sensíveis a clorexidina nos tempos de 30″, 60″ e 300″, ao iodo glicerinado em 60″ e 300″, ao hipoclorito de sódio em 60″ e 300″ e ao iodo apenas em 300″. Em relação aos tratamentos térmicos, a pasteurização rápida foi o procedimento no qual houve maior índice de resistência (64,44%) por parte das estirpes de leveduras. A mastite provocada por fungos está se tornando um problema crescente devido ao aumento da participação deste microrganismo no desenvolvimento de mastite em bovinos. Além disso, resistência apresentada ao tratamento térmico pelas cepas de Candida representa um problema para o consumo de leite, significando um risco para a saúde pública. Uma conclusão adicional é a importância da realização periódica de avaliações de sensibilidade dos microrganismos aos desinfetantes utilizados, de forma a garantir a eficácia da desinfecção dos tetos / Abstract: Mastitis is one of the most serious problems in dairy farms. The objectives of this study were to identify yeasts involved in cases of bovine mastitis; evaluate the in vitro susceptibility of strains of Candida spp. Against four disinfectants used in the pre and post-dipping and evaluate the resistance of these strains before pasteurization and boiling. Fifty-five samples (12,8%) were positive for Candida. The most isolated species were C. krusei (34,6%), C. parapsilosis (25,4%), C. tropicalis (18,2%) and C. albicans (12,8%). As active drugs were used chlorhexidine (2,0%), iodine (0,8%), glycerin iodine (0,8%) and sodium hypochlorite (1,0%) at specific intervals of four treatment (15", 30", 60" and 300"). One hundred percent of Candida was found to be sensible to chlorhexidine at 30″, 60″, and 300″, to iodine glycerin at 60″ and 300″, to sodium hypochlorite at 60″, and 300″, to iodine only at 300″. In relation to thermal treatments, pasteurization was the quick procedure in which there was a higher resistance index (64,44%) by yeast strains. Moreover, t he resistance of Candida spp. strains after thermal treatment presents a problem for milk consumption what represents a potential risk for public health. A further conclusion was that it is important to undertake a periodic evaluation of the sensibility of microorganisms to the disinfectants commonly used, to guarantee the efficacy of the process of teat disinfecting / Mestre

no / A milk pasteurization process is a nonlinear process and multivariable interacting system. This makes it difficultly to control by the conventional on-off controllers. Even if the on-off controller can managed the milk temperatures in the holding tube and the cooling stage of the plate pasteurizer according to the plant's requirements, the dynamic profiles of the milk temperature are oscillating around a desired value. Consequently, this work is aimed at improving the control performance by a multi-variables control approach with model predictive control (MPC). The proposed algorithm was tested in the case of set point tracking under nominal condition gathered by the real observation. To compare the performance of the MPC controller, a model-based control approach of generic model control (GMC) coupled with cascade control strategy is taken into account. The simulation results demonstrated that a proposed control algorithm performed well in keeping both the milk and water temperatures at the desired set points without any oscillation and overshoot. Because of the predictive control strategy, the control response for MPC was less drastic control action compared to the GMC.

CNPQ / O leite é uma das principais fontes de nutrientes da dieta humana e é um alimento que acompanha o ser humano durante toda a vida, tanto como leite de consumo como através de seus derivados. O leite pode apresentar contaminação oriunda de diversas fontes, relacionados desde a ordenha até o processo de beneficiamento do mesmo. Dentre esses contaminantes, destacam-se as micotoxinas, que são metabólitos tóxicos produzidos por fungos em condições de estresse. Estudos correlacionam a ocorrência de micotoxinas em leite e derivados lácteos, com ênfase na aflatoxina M1 (AFM1) que é regulamentada pela legislação vigente. Apesar da maior parte da literatura afirmar que a aflatoxina B1 (AFB1) é completamente convertida em AFM1, resultados preliminares tem sugerido que isso não é verdadeiro, o que vem a justificar que a mesma passe, também, a ser analisada, uma vez que a toxicidade da AFB1 é maior que a da AFM1. Na área de leite e derivados lácteos, estudos têm sugerido que as aflatoxinas, em especial a AFM1, localizam-se predominantemente nas frações proteicas. Porém, a elucidação da interação entre AFM1 e fração proteica permanece sem conclusão definitiva, o que sugere um campo amplo de estudo nesta área. Ainda, tendo em vista que a concentração de aflatoxinas é predominante na fração proteica e que pode haver uma interação química entre esta fração e aflatoxinas, os tratamentos térmicos aos quais o leite é submetido podem causar alterações significativas nas estruturas dessas proteínas e, por conseguinte, nas interações entre proteínas e AFM1 e AFB1. Portanto, o entendimento da natureza das ligações entre as AFM1 e AFB1 às proteínas do leite é imprescindível para a compreensão da biodisponibilidade dessas micotoxinas em animais e seres humanos. Desta forma, o objetivo do trabalho foi verificar o efeito do tratamento térmico e da digestibilidade sobre a interação proteína-aflatoxina. Para isso, foram contaminados amostras de solução de caseína bovina e leite desnatado com AFB1 (200 µg.L-1) e AFM1 (20 µg.L-1), posteriormente submetidas a pasteurização e digestão in vitro. As determinações realizadas consistiram na quantificação das AFLB1 e M1 por Cromatografia à Líquido de Ultra Alta Eficiência, Espectroscopia na região do infra vermelho (FTIR), Calorimetria Exploratória Diferencial (DSC) e Espectroscopia de fluorescência. Não houve redução da concentração de AFB1 e AFM1 após o tratamento térmico e a bioacessibilidade foi de 91,2% 70,5% e 90,9% e 69,7%, respetivamente, para caseína bovina e leite desnatado. Avaliando quantitativamente as estruturas secundárias da solução de caseína bovina e leite desnatado contaminados com AFB1 e AFM1 as principais mudanças ocorreram nas estruturas β-volta, β-anti e β-folha. Com a análise de DSC observou-se picos exotérmicos para ambos os ensaios, com variação de entalpia (∆H) após cada ensaio. Em relação aos espectros de fluorescência, foi possível verificar que as AFB1 e AFM1 promoveram redução da fluorescência original das proteínas lácteas. Pelos resultados obtidos, é possível concluir que a concentração das AFB1 e M1 não foram reduzidas pela temperaturaempregada, provavelmente pela interação proteínas do leite-aflatoxina, resultando numa bioacessibilidade relativamente elevada. / Milk and derivates are one of the main sources of nutrients of the human diet and is a food that follow's man during all of your life. The milk may be contaminated from several sources, related since milking until the beneficiation process. Among these contaminants, highlights are the mycotoxins, which are toxic metabolites produced by fungus in conditions of stress. Studies related to the occurrence of mycotoxins in milk and milk products, with the emphasis on aflatoxin M1 (AFM1) which is ruled by Brazilian law. While most of the literature stating that aflatoxin B1 (AFB1) is completely converted into AFM1, preliminary results have suggested that this is not true, justifying that it passes also to analyze because the toxicity of AFB1 is greater than the AFM1. In the milk and dairy products, studies have suggested that aflatoxins, in particular AFM1, are located predominantly in protein fractions. However, the elucidation of the interaction between AFM1 and protein fraction remains without definitive conclusion, suggesting a large broad field of study in this area. Also considering that the concentration of aflatoxins are prevalent in the protein fractions and can have a chemical interaction between these fractions and aflatoxins, the thermal treatments that the milk is subjected can cause significant changes in these proteins structures and consequently in interactions between proteins and AFM1 and AFB1. Therefore, the knowledge of nature of the links between AFM1 and AFB1 to milk proteins is indispensable for understanding the bioavailability of these mycotoxins in animals and humans. Thus, the aim of this study was to investigate the effect of thermal treatment and the digestibility of the interaction protein-aflatoxin. For this, samples of bovine casein solution and skimmed milk were contaminated with AFB1 (200 μg.L-1) and AFM1 (20 μg.L-1), and then submitted to pasteurization and in vitro digestion. The carried analyzes consisted in quantifying AFB1 and AFM1using high performance liquid chromatography, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and fluorescence spectroscopy. There was no reduction in the concentration of AFB1 and AFM1 and after the thermal treatment the bioaccessibility was 91.2% and 70.5%, 90.9% and 69.7%, respectively, for bovine casein and skim milk. In quantitative assessments of the secondary structures of bovine casein and skim milk contaminated with AFB1 and AFM1 the major changes occurred in the β-turn structures, β-anti and β-sheet. With the DSC analysis was observed exothermic peaks for both tests, the change of enthalpy (∆H) after each test. Regarding the fluorescence spectra, we found that AFB1 and AFM1 promoted reduction of the original fluorescence of milk proteins. From the results, it may be concluded that the concentration of AFB1 and M1 not been reduced by the temperature applied, probably by the interaction between milk protein and aflatoxin, resulting in a relatively high bioaccessibility.

CNPQ / O leite é uma das principais fontes de nutrientes da dieta humana e é um alimento que acompanha o ser humano durante toda a vida, tanto como leite de consumo como através de seus derivados. O leite pode apresentar contaminação oriunda de diversas fontes, relacionados desde a ordenha até o processo de beneficiamento do mesmo. Dentre esses contaminantes, destacam-se as micotoxinas, que são metabólitos tóxicos produzidos por fungos em condições de estresse. Estudos correlacionam a ocorrência de micotoxinas em leite e derivados lácteos, com ênfase na aflatoxina M1 (AFM1) que é regulamentada pela legislação vigente. Apesar da maior parte da literatura afirmar que a aflatoxina B1 (AFB1) é completamente convertida em AFM1, resultados preliminares tem sugerido que isso não é verdadeiro, o que vem a justificar que a mesma passe, também, a ser analisada, uma vez que a toxicidade da AFB1 é maior que a da AFM1. Na área de leite e derivados lácteos, estudos têm sugerido que as aflatoxinas, em especial a AFM1, localizam-se predominantemente nas frações proteicas. Porém, a elucidação da interação entre AFM1 e fração proteica permanece sem conclusão definitiva, o que sugere um campo amplo de estudo nesta área. Ainda, tendo em vista que a concentração de aflatoxinas é predominante na fração proteica e que pode haver uma interação química entre esta fração e aflatoxinas, os tratamentos térmicos aos quais o leite é submetido podem causar alterações significativas nas estruturas dessas proteínas e, por conseguinte, nas interações entre proteínas e AFM1 e AFB1. Portanto, o entendimento da natureza das ligações entre as AFM1 e AFB1 às proteínas do leite é imprescindível para a compreensão da biodisponibilidade dessas micotoxinas em animais e seres humanos. Desta forma, o objetivo do trabalho foi verificar o efeito do tratamento térmico e da digestibilidade sobre a interação proteína-aflatoxina. Para isso, foram contaminados amostras de solução de caseína bovina e leite desnatado com AFB1 (200 µg.L-1) e AFM1 (20 µg.L-1), posteriormente submetidas a pasteurização e digestão in vitro. As determinações realizadas consistiram na quantificação das AFLB1 e M1 por Cromatografia à Líquido de Ultra Alta Eficiência, Espectroscopia na região do infra vermelho (FTIR), Calorimetria Exploratória Diferencial (DSC) e Espectroscopia de fluorescência. Não houve redução da concentração de AFB1 e AFM1 após o tratamento térmico e a bioacessibilidade foi de 91,2% 70,5% e 90,9% e 69,7%, respetivamente, para caseína bovina e leite desnatado. Avaliando quantitativamente as estruturas secundárias da solução de caseína bovina e leite desnatado contaminados com AFB1 e AFM1 as principais mudanças ocorreram nas estruturas β-volta, β-anti e β-folha. Com a análise de DSC observou-se picos exotérmicos para ambos os ensaios, com variação de entalpia (∆H) após cada ensaio. Em relação aos espectros de fluorescência, foi possível verificar que as AFB1 e AFM1 promoveram redução da fluorescência original das proteínas lácteas. Pelos resultados obtidos, é possível concluir que a concentração das AFB1 e M1 não foram reduzidas pela temperaturaempregada, provavelmente pela interação proteínas do leite-aflatoxina, resultando numa bioacessibilidade relativamente elevada. / Milk and derivates are one of the main sources of nutrients of the human diet and is a food that follow's man during all of your life. The milk may be contaminated from several sources, related since milking until the beneficiation process. Among these contaminants, highlights are the mycotoxins, which are toxic metabolites produced by fungus in conditions of stress. Studies related to the occurrence of mycotoxins in milk and milk products, with the emphasis on aflatoxin M1 (AFM1) which is ruled by Brazilian law. While most of the literature stating that aflatoxin B1 (AFB1) is completely converted into AFM1, preliminary results have suggested that this is not true, justifying that it passes also to analyze because the toxicity of AFB1 is greater than the AFM1. In the milk and dairy products, studies have suggested that aflatoxins, in particular AFM1, are located predominantly in protein fractions. However, the elucidation of the interaction between AFM1 and protein fraction remains without definitive conclusion, suggesting a large broad field of study in this area. Also considering that the concentration of aflatoxins are prevalent in the protein fractions and can have a chemical interaction between these fractions and aflatoxins, the thermal treatments that the milk is subjected can cause significant changes in these proteins structures and consequently in interactions between proteins and AFM1 and AFB1. Therefore, the knowledge of nature of the links between AFM1 and AFB1 to milk proteins is indispensable for understanding the bioavailability of these mycotoxins in animals and humans. Thus, the aim of this study was to investigate the effect of thermal treatment and the digestibility of the interaction protein-aflatoxin. For this, samples of bovine casein solution and skimmed milk were contaminated with AFB1 (200 μg.L-1) and AFM1 (20 μg.L-1), and then submitted to pasteurization and in vitro digestion. The carried analyzes consisted in quantifying AFB1 and AFM1using high performance liquid chromatography, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and fluorescence spectroscopy. There was no reduction in the concentration of AFB1 and AFM1 and after the thermal treatment the bioaccessibility was 91.2% and 70.5%, 90.9% and 69.7%, respectively, for bovine casein and skim milk. In quantitative assessments of the secondary structures of bovine casein and skim milk contaminated with AFB1 and AFM1 the major changes occurred in the β-turn structures, β-anti and β-sheet. With the DSC analysis was observed exothermic peaks for both tests, the change of enthalpy (∆H) after each test. Regarding the fluorescence spectra, we found that AFB1 and AFM1 promoted reduction of the original fluorescence of milk proteins. From the results, it may be concluded that the concentration of AFB1 and M1 not been reduced by the temperature applied, probably by the interaction between milk protein and aflatoxin, resulting in a relatively high bioaccessibility.

Thesis (MNutr (Interdisciplinary Health Sciences. Human Nutrition))--Stellenbosch University, 2008. / Objective: Primary: To investigate the effect of pasteurisation on the composition of expressed breast milk from HIV positive mothers and its adequacy in relation to the growth of their VLBW premature infants. Methods: A descriptive, prospective case-controlled pilot study was performed in 3 regional state hospitals in the Western Cape, South Africa. The control and study groups consisted of 12 HIV negative and 11 HIV positive mothers, with their VLBW premature infants, respectively. All mothers (19 - 35 years old) belonged to the Xhosa ethnic group. All infants were born <34 weeks gestation and birth weight <1500g. Eight breast milk samples were collected on days 6, 7, 13, 14, 20, 21, 27 and 28 from all mothers during the first 28 days after birth. Breast milk was expressed by hand or pump from either the right or left breast. Half of each breast milk sample was kept raw. The remaining sample was Pretoria pasteurised, after which both samples were subdivided into 3 or 4 aliquots to determine energy, protein, carbohydrate, fat, folate, calcium, phosphorus, magnesium, sodium, otassium, iron, copper, zinc content and HI viral load (study group only). The mothers’ dietary intake during pregnancy and lactation was obtained by means of a quantitative food frequency questionnaire and repeated 24-hour recall respectively. The infants’ dietary intake was recorded daily. Mothers’ anthropometric measurements taken at study entry and exit were weight, height and mid-upper arm circumference. All infants’ daily weight, as well as length and head circumference at birth and on day 28 postpartum was obtained. Biochemical analysis was performed on the blood samples obtained at study entry and exit from all mothers and infants. For statistical analysis, Statistica® (release no 7, 2006) was used for repeated measures analysis of variance (ANOVA) to determine the effect of HIV, pasteurisation, milk expression and time on the composition of the breast milk. Results: There was no significant difference in the studied macro- and micronutrient composition between raw or pasteurised expressed breast milk from HIV positive and HIV negative mothers with premature infants. A significant decline in breast milk protein (p<0.01), magnesium (p=0.045), potassium (p=0.002), zinc (p<0.01) and copper (p=0.03) content was observed for the whole study population over time, while folic acid content increased significantly (p=0.012) over time. The sodium/potassium ratio of both groups remained strongly indicative of the presence of sub-clinical mastitis. A significant (p=0.03) greater mean volume of milk was obtained with pump [42.5 Standard Deviation (SD) 18.1 ml], compared to hand expression [36.7 (16.7) ml]. Method of expression did not result in a significant difference in breast milk composition for any of the nutrients studied. Eight (35%) infants were born SGA while 21 (91%) infants were SGA on day 28. The infants gained a mean of 16.37 (4.5) g/kg/day (i.e. 91% of the recommended growth rate of >18g/kg/day) from the day on which birth weight was regained. The control and study group infants respectively consumed a mean of 3.27 (1.36) and 3.21 (1.36) g protein/kg/day and 138.1 (33.8) and 142.3 (33.8) kcal total energy/kg/day. This corresponds to a PER of 2.6 (control group) and 2.5 (study group) respectively, which cannot provide for the increased growth needs of the SGA infant in need of catch-up growth. Six infants experienced an incident of Grade 1 NEC which resolved and all completed the study. Two (18%) HIV-exposed infants were found to be HIV positive at 28 days post delivery. Four participating infants died. No adverse event or mortality was related to the study protocol as no intervention was undertaken. Conclusion: HIV positive Xhosa mothers provide as nutritious breast milk to their VLBW premature infants as HIV negative Xhosa mothers. Maternal nutrient intake during pregnancy and lactation did not have a significant effect on the nutritional composition of breast milk, except for folate content.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2008 / Local government (LG) is under increasing pressure from the milk industry and consumers regarding their ability and willingness to carry out their mandate with regard to the quality control of milk, especially in the informal sector. The government and the milk industry currently have programmes underway to stimulate economic activities in the informal sector, targeting emerging cattle farmers for the production of milk as part of government’s Accelerated Shared Growth Initiative of South Africa (ASGISA). These initiatives further increase the number of informal milk producers and distributors, which holds a further challenge to regulatory authorities. At the same time, the quality of milk from the informal milk-producing sector poses a serious public health concern. Most of the milk produced and sold by the informal sector is raw (unpasteurised), which does not meet the minimum statutory requirements, and the milking practices applied by the informal sector also do not comply with best practice compliance standards. Local authorities (LAs) are statutorily responsible for registering milking parlours and controlling milk hygiene quality from production stage to purchase stage in order to ensure safe and wholesome dairy products to the consumer. Therefore, LG should play an increasingly important role in ensuring that safe and wholesome milk is produced and distributed to the consumers. All metropolitan municipalities (metros) and district municipalities (DMs) should be authorised by the Ministry of Health to enforce the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 1972) through their authorised officials – mainly environmental health practitioners (EHPs). Secondly, LG should have specific programmes, systems and resources to register, monitor, evaluate and control milk production and distribution outlets for continued compliance