Influence of physical state of farm housing and processing facilities on quality and safety of dairy milk products.

Doctor of Philosophy in Animal and Poultry Science. University of KwaZulu-Natal, Pietermaritzburg, 2018.The broad objective of the study was to determine the influence of physical state of farm housing and milk processing facilities on the quality and safety of milk and its products. Data collected from urban areas (n =135) and non-urban areas (n =135) households were used to investigate consumer perceptions of milk safety and consumption preferences of dairy products. Data collected from large-scale dairy farmers (n=158) and small-scale dairy farmers (n=186) were used to investigate the perception of milk producers on milk quality and safety. Milk records collected from large-scale dairy farms (n =78) and small-scale farms (n =126) were used to determine the effect of physical state of farm housing and milking practices on total bacteria counts (TBC), somatic cell counts (SCC), protein, butterfat (BF), solids non-fat (SNF), lactose and total solids (TS). Milk records collected from large-scale (n =12) and small-scale (n = 15) dairy processors were used to estimate the influence of physical state of milk processing facilities on presence of E. coli and coliforms in buttermilk. Urban households were 2.8 times more likely to consume fresh milk compared to their non-urban counterparts (P < 0.05). Households from urban areas were twice more likely to purchase fresh milk from kiosks, while households from non-urban areas were five times more likely to buy fresh milk from vendors. The likelihood of appearance, quality and nutritional value being important to households during selection of milk products was higher in urban locations compared to non-urban locations (odds ratio estimates of 4.29, 4.49 and 6.75, respectively). Knowledge and awareness of milk safety issues was more important to urban households. Large-scale farmers were three times more likely to consider breed affecting milk quality compared to their small- scale counterparts. Post milking contamination of milk was perceived to occur during transportation by small-scale farmers, whilst large-scale farmers ranked storage as an important source of contamination post-milking. The likelihood of milk safety being important was twice higher in large farms compared to small-scale farms (P < 0.05. The majority (70%) of large-scale farms had milking parlour doors, windows and fly proofing in poor physical state. More than fifty percent of small-scale farms had milking parlour doors, windows and fly proofing in good physical state (P < 0.01). Most of the large-scale farms used pumps to deliver their milk to storage tanks whilst most of the small-scale farmers used the pouring method (P < 0.05). The TBC and SCC in milk from dairy farms where the wash rooms that had doors, floors, walls and ventilation were in a good physical state were higher than from those farms where the wash rooms were in poor physical state (P < 0.05). Farms that used machine milking and automatic milking cleanings system had lower TBC and SCC in milk compared to farms that used manual milking or hand washing (P < 0.05). The butterfat and protein content in milk from dairy farms with milking facilities that had poor physical state of ceilings, ventilation and floors was lower than those in good physical state (P < 0.05). The butterfat, protein, lactose and solids non-fat (SNF) content in milk from farms that utilised hand milking was higher than dairy farms that used milking machines (P < 0.05). The likelihood of buttermilk from processors with buildings, processing and packaging areas that had poor physical state of drains, roofs, fly-proofing, windows having E. coli and coliforms was 1.2 times higher than those facilities in good physical state. Processors without quality assurances systems or food safety training were twice more likely to produce buttermilk contaminated by E. coli and coliforms (P < 0.05). Poor physical state of ceilings, doors and floors and poor drainage systems at farms results in production of milk with high bacterial count and presence of E. coli and coliforms in buttermilk

Alleviation of conceptual difficulties in grade 12 mechanics by addressing the challenges emanating from alternative conceptions

A thesis submitted to the Faculty of Education in fulfillment of the requirements for the Degree of Doctor of Education (Science Education) in the Department of Mathematics, Science and Technology Education at the University Of Zululand, South Africa, 2012.This study sought to determine the conceptual difficulties experienced by grade 12 physical science learners with regard to mechanics. It also sought to identify the most prevalent alternative conceptions among grade 12 physical science learners in the area of mechanics, and develop interventions to alleviate the identified conceptual difficulties and alternative conceptions. In this regard, the study compared the effectiveness of a traditional lecture, outcomes-based education (OBE) and blended instructional approaches in alleviating or overcoming the identified conceptual difficulties and alternative conceptions concerning mechanics. The aspects of Mechanics dealt with in this study were: work and energy, motion on the inclined surfaces, projectile motion, force concept, static objects and Newton’s Third Law of Motion. In addressing the above research problem, the study developed and presented a theoretical and conceptual framework derived from the review of relevant literature, in line with the research questions of the study. The conceptual framework developed was based on the constructivist views of learning. A total of one hundred and forty (140) grade 12 physical science learners from Empangeni Education District were involved in this study. The study followed the quasi-experimental non-equivalent comparison-group research design. Though quantitative in design, the study also used qualitative research methods. Thus, both quantitative and qualitative data were collected. From the quantitative data, the findings showed highly statistically significant gains between pre- and post-test scores of OBE and blended approaches in particular. The average normalised gain score concept was also used determine the most effective instructional approach. Convenience sampling was used to select participating schools. A Test in Basic Mechanics (TBM) was designed to assess the learners’ understanding of the most basic concepts in mechanics. The TBM was administered both as a pre- and post-test to the three groups (traditional, OBE and blended groups) to determine the level of experience, knowledge, pre-existing alternative conceptions, level of understanding of basic concepts and principles on mechanics topics identified at the start of the investigation. As a pre-test, the TBM was also used to identify the specific conceptual difficulties and alternative conceptions in mechanics. The identification of the conceptual difficulties and alternative conceptions after the pre-test was followed by three instructional interventions (the traditional, OBE and the blended approach). The three interventions addressed the same mechanics topics mentioned above. These interventions were then followed by post-tests to ascertain the effectiveness of the interventions in addressing the identified conceptual difficulties and alternative conceptions, as well as any conceptual difficulties and alternative conceptions which were resistant to change even after the interventions. The results revealed that the learners experienced conceptual difficulties with regard to (a) resolving the components of the weight; (b) work concept; (c) work-energy theorem application; (d) kinetic energy concept; and (e) principle of conservation of mechanical energy application. Regarding the most prevalent alternative conceptions in mechanics, learners held eight alternative conceptions related to kinematical and dynamical concepts. Alternative conceptions held by the learners in mechanics concerned the following: (a) the acceleration and velocity of projectile motion; (b) weight/mass of an object as related to Newton’s Third Law of motion; (c) force concept; (d) objects in motion; (e) static objects; (f) Newton’s Third Law of motion; (g) acceleration of projectiles; and (h) active force. The average normalised gains for the traditional, OBE and blended instructional approaches were (g) = 0,20; (g) = 0,30; and (g) = 0,60, respectively. This confirmed the statistical analysis computed using One Way Analysis of Variance (ANOVA), that the blended instructional approach was the most effective instructional approach in alleviating the conceptual difficulties and alternative conceptions in mechanics. Qualitative data showed that most of the pre-existing conceptual difficulties and alternative conceptions appeared to have been alleviated, although not completely overcome by the interventions. There were statistically significant differences that were found among the traditional, OBE and blended instructional interventions. It is therefore noted that the blended instructional approach to teaching and learning can have a significant contribution to overcoming conceptual difficulties and alternative conceptions in mechanics, and the improvement of efficiency of learning. The study concluded that conceptual difficulties and alternative conceptions in mechanics could best be alleviated using the blended approach to teaching and learning. A number of recommendations were also made. Some alternative conceptions were resistant to change in the face of the traditional lecture based teaching. This meant that a more powerful teaching technique had to be devised. Thus, physical science educators should be encouraged to use the blended approach to teaching and learning in order to accommodate all learners in a class. Blended teaching and learning is mixing of different teaching and learning environments – mainly manifested in combining face-to-face instruction with the computer mediated-instruction. In one class of learners there are different learner characteristics. Learners learn in different ways like learning through lecture (telling), discussion, problem solving, practical work, discovering, experimenting, using pictures and diagrams, videos and demonstrations

Challenges facing physical science educators in the implementation of the National Curriculum statement: the case of the Empangeni Education District

A dissertation submitted to the Faculty of Education in partial fulfilment of the requirements for the Masters of Education in the Department of Mathematics, Science and Technology Education at the University of Zululand, South Africa, 2009.This study looked at the implementation of the NCS physical science as a major curriculum change. As Imenda (2002:4) states "curriculum change entails that educators, learners, administrators, and all those with a part to play in the actualisation of the new curriculum have to see and do things differently". He further asserts that "this invariably means embracing a new system of doing things in terms of a sound philosophical basis, curriculum content description, beliefs, values, convictions and practices". He further posits that "the transition from an 'old' curriculum to a new one could therefore present difficult challenges and problems". According to Imenda (2002:4), "the espousal of OBE by South Africa's Ministry of Education to apply to all levels of the education system has presented a number of major challenges". Indeed, there are many challenges facing physical science educators in the implementation of OBE, including overcrowding, language mismatching, teacher unpreparedness, non-delivery of OBE resources, inadequate facilities and resources (Adler & Reed, 2002:60-65; Jacobs, Gawe & Vakalisa, 2002:106-107 & De Waal, 2004:63-66). In particular, student assessment is an integral part of the outcome-based approach to curriculum design and implementation. Accordingly, the implementation of valid and reliab!e assessment procedures is a centre piece 1 of outcomes-based education (OBE). The paradigm shift from the traditional curriculum to an OBE curriculum requires changes to be reflected in assessment practices. Thus, unless assessment is properly aligned with the curriculum reform and teaching, the desired changes in education will be extremely difficult, if not impossible, to realise. The current reform initiative in science education emphasizes the importance of teaching learners to be critical thinkers and problem solvers. Assessing whether learners understand basic science concepts and can use them to solve problems requires an approach very different from traditional tests that primarily measure the recall of isolated facts. As Rasool (1999: 177) points out: The traditional educational paradigm prevalent in schools is characterized by a heavily content-driven, teacher centered approach. Subjects are broken down in terms of rigidly defined syllabuses and tend to be knowledge focused rather than performance focused. While methodologies vary, the role of the teacher as a subject matter expert is largely that of provider of content. The following points are noted from the traditional curriculum: • Learners are often passive recipients of knowledge. • Emphasis is on memory, practice and rote learning. • Promotion of learners is based mainly on pencil and paper examinations. • Little or no emphasis is on creativity and the curriculum is overloaded with content; no attention is given to skill. • No emphasis on co-operative learning and discovery learning. • Competencies, knowledge and skills are not improved. 2 • Skills acquired outside school are regarded as inferior and largely not recognized (Department of Education, 1997: 27). In the new curriculum, the full scientific power of pupils is assessed. Students' performance is compared with established criteria"; students are viewed as active participants in the assessment process; assessment is regarded as continual and recursive. Overall, outcome-based assessment focuses on work done, assesses understanding and is motivational in nature (Lorraine, 1998: 58)

Perceptions of Factors Affecting Milk Quality and Safety among Large- and Small-Scale Dairy Farmers in Zimbabwe

The study investigated the perceptions of milk producers on milk quality and safety. Randomly selected large-scale farmers (n = 158) and small-scale farmers (n = 186) were surveyed using semistructured questionnaires. An ordinal logistic regression was used to estimate the probability of farmers considering milk quality and safety important. Large-scale farmers were 3 times more likely to consider that breed affects milk quality compared to their small-scale counterparts. Farmers aged over 30 years were 3 times more likely to indicate that hygiene affected milk quality. The likelihood of milk transportation affecting its quality was 4 times higher in small-scale farmers compared to large-scale producers. Postmilking contamination of milk was perceived to occur during transportation by small-scale farmers, whilst commercial farmers ranked storage as the important source of contamination after milking. Udder diseases were ranked first by large-scale farmers while small-scale farmers ranked milking environment as the major cause of milk spoilage. The likelihood of milk safety being important was two times higher in large farms compared to small-scale farms. Intervention programmes on milk safety should mainly target small-scale dairy farmers since they are less concerned about milk quality and safety

Does physical state of farm housing and milking practices affect total bacteria and somatic cell count of cow milk?

The study determined the effect of physical state of farm housing on total bacteria and somatic cell count (SCC) of cow milk. Milk records collected at Dairy Services Zimbabwe were used. Effects of physical state of ceilings, doors, ventilation, walls, drains, fly-proofs, windows and roof type on total bacterial count (TBC) in milk, and SCC were determined using general linear models procedure. Poor physical state of ceilings, doors and floors in milking parlors, wash rooms and bulk tank rooms result in high TBC and SCC in milk (p < 0.05). Poor ventilation in the bulk tank room results in high TBC in milk (p < 0.05). Floors, doors, and ceilings of milking houses should be kept in sound condition and good repair in order minimize TBC and SCC in raw milk. Practical applications: Understanding how physical state of farm houses and management practices affect total bacterial count and somatic cell count in fresh milk enables farmers and regulatory agencies to put in corrective action to reduce bacterial contamination of milk at farm level. This helps keep the population of disease causing bacteria in raw milk, which is widely consumed by human beings, as low as possible. It also helps reduce contamination by some resistant bacteria that might survive processing and cause further defects in milk products. The shelf-life of the milk and its products is, thus, improved. Reducing bacterial and somatic cell count in raw milk also helps the milk producers to score high milk grades on the market and, thus, fetch high prices

Effect of structural condition of milk processing facilities and food safety systems on Escherichia coli and coliforms presence in cultured buttermilk

The study investigated the effect of structural conditions of milk processing facilities and food safety systems on E. coli and coliform presence in buttermilk. Milk records collected by Dairy Services Zimbabwe (DSZ) from large-scale dairy milk processors (n=12) and small-scale farms (n=15) were analysed. Binomial logistic regression was used to estimate the likelihood of E. coli or coliforms being present in cultured buttermilk as a function of the hygiene level and structural adequacy of the processors. The likelihood of having E. coli and coliforms in cultured milk from processors with poor sanitary premises was two times higher than that from processors with good sanitary premises (P<0.05). Milk processors that used unfiltered water were 1.77 times more likely to produce cultured buttermilk contaminated with E. coli (P<0.05). Processors without food safety systems like hazard analysis critical control point (HACCP) systems were more than twice likely to produce cultured buttermilk contaminated by E. coli and coliforms (P<0.05). Poor structural condition of roofs, windows, insect-proof screens, and drainage in small- and large-scale processing facilities results in production of cultured buttermilk that is contaminated by E. coli and coliforms

Effect of Structural Condition of Milk Processing Facilities and Food Safety Systems on <i>Escherichia coli</i> and Coliforms Presence in Cultured Buttermilk

The study investigated the effect of structural conditions of milk processing facilities and food safety systems on E. coli and coliform presence in buttermilk. Milk records collected by Dairy Services Zimbabwe (DSZ) from large-scale dairy milk processors (n=12) and small-scale farms (n=15) were analysed. Binomial logistic regression was used to estimate the likelihood of E. coli or coliforms being present in cultured buttermilk as a function of the hygiene level and structural adequacy of the processors. The likelihood of having E. coli and coliforms in cultured milk from processors with poor sanitary premises was two times higher than that from processors with good sanitary premises (P&lt;0.05). Milk processors that used unfiltered water were 1.77 times more likely to produce cultured buttermilk contaminated with E. coli (P&lt;0.05). Processors without food safety systems like hazard analysis critical control point (HACCP) systems were more than twice likely to produce cultured buttermilk contaminated by E. coli and coliforms (P&lt;0.05). Poor structural condition of roofs, windows, insect-proof screens, and drainage in small- and large-scale processing facilities results in production of cultured buttermilk that is contaminated by E. coli and coliforms.</jats:p