title: Review: Extrusion processing and properties of protein-based thermoplastics

authors: Verbeek, Casparus Johan R.

subjects: extrusion

abstract: Increasing interest in competitive, sustainable, and biodegradable alternatives to petroleum-based plastics has encouraged the development of protein-based plastics. The formation of a homogeneous protein melt during extrusion occurs through: denaturation, dissociation, unraveling, and alignment of polymer chains. The presence of covalent cross-links is unfavorable, decreasing chain mobility, increasing viscosity and preventing homogenization. Proteins have high softening temperatures, often above their decomposition temperatures. To avoid degradation, the required chain mobility is achieved by plasticizers. By understanding a protein's physiochemical nature, additives can be selected that lead to a bioplastic with good processability. The final structural and functional properties are highly dependent on the protein and processing conditions.

text: Review: Extrusion processing and properties of protein-based thermoplastics Increasing interest in competitive, sustainable, and biodegradable alternatives to petroleum-based plastics has encouraged the development of protein-based plastics. The formation of a homogeneous protein melt during extrusion occurs through: denaturation, dissociation, unraveling, and alignment of polymer chains. The presence of covalent cross-links is unfavorable, decreasing chain mobility, increasing viscosity and preventing homogenization. Proteins have high softening temperatures, often above their decomposition temperatures. To avoid degradation, the required chain mobility is achieved by plasticizers. By understanding a protein's physiochemical nature, additives can be selected that lead to a bioplastic with good processability. The final structural and functional properties are highly dependent on the protein and processing conditions.

year: 2010

title: Bacterial Community Analysis of Meat Industry Conveyor Belts

authors: Mills, John

subjects: microbial ecology

abstract: At the commencement of this study, some sensitive overseas markets were rejecting chilled vacuum-packed New Zealand lamb due to higher than expected total viable counts, and counts of Enterobacteriaceae, a family of bacteria used to indicate sanitary condition. 
Of the many factors that influence the bacterial composition of chilled lamb in the overseas marketplace, the meat producer can only exert significant control over:
Hygiene, ensuring the bacterial viable count on the meat prior to packaging is as low as possible, and comprised of as few species as possible that are capable of anaerobic growth at chilled meat temperatures.
Maintaining the pH of the meat within acceptable limits, by careful animal selection and minimal pre-slaughter stress.
Refrigeration temperatures, through rigorous maintenance of the cold-chain.
The type of preservative packaging used, which is often limited by regulation in the marketplace.
Initial work established that the bacterial microbiota present on the meat contact surfaces in the butchering facilities at some premises, in particular conveyor belting, was excessive and comprised of species that contributed to the high counts on the meat reported above.
As a means of improving the hygiene of this process, this study investigated the hypothesis that some species of bacteria were able to form biofilms on the conveyor belt contact surfaces, becoming reservoirs for cross-contamination. This hypothesis was not been proven by this work; the results showing that biofilms were not present and that adequate hygiene of these surfaces instead depends on the ability to remove all meat-based residues from them at the completion of each day's processing.
For premises operating interlocking belts from one manufacturer (Intraloxreg), a clean-in-place system is now available that is able to achieve this. Premises operating conventional disinfectant and water sanitisation of either continuous or interlocking belts must ensure that meat residue is completely removed before disinfection.
The majority of New Zealand meat industry premises can now demonstrate that their hygienic processes in this area are under control. 
The microbiota of conveyor belting in this study was found to consist of bacteria from five taxonomic groups; the Flavobacteriaceae, the Actinomycetales, the Bacillus/Clostridium group, and the alpha and gamma branches of the Proteobacteria. The genera present on belts from premises whose hygiene was found to be in control did not contain species known to cause food-borne disease or spoilage of vacuum packaged meats.
The bacterial viable count remains the most effective method available at this time for monitoring conveyor belt hygiene. Attempts to develop a monitoring system based on microscopy of an in-situ sampling device were unsuccessful due to an inability to penetrate the meat residue matrix. Denaturing Gradient Gel Electrophoresis (DGGE) may offer an alternative for rapid investigation of diversity, but further work is required before this can be validated for routine use.

text: Bacterial Community Analysis of Meat Industry Conveyor Belts At the commencement of this study, some sensitive overseas markets were rejecting chilled vacuum-packed New Zealand lamb due to higher than expected total viable counts, and counts of Enterobacteriaceae, a family of bacteria used to indicate sanitary condition. 
Of the many factors that influence the bacterial composition of chilled lamb in the overseas marketplace, the meat producer can only exert significant control over:
Hygiene, ensuring the bacterial viable count on the meat prior to packaging is as low as possible, and comprised of as few species as possible that are capable of anaerobic growth at chilled meat temperatures.
Maintaining the pH of the meat within acceptable limits, by careful animal selection and minimal pre-slaughter stress.
Refrigeration temperatures, through rigorous maintenance of the cold-chain.
The type of preservative packaging used, which is often limited by regulation in the marketplace.
Initial work established that the bacterial microbiota present on the meat contact surfaces in the butchering facilities at some premises, in particular conveyor belting, was excessive and comprised of species that contributed to the high counts on the meat reported above.
As a means of improving the hygiene of this process, this study investigated the hypothesis that some species of bacteria were able to form biofilms on the conveyor belt contact surfaces, becoming reservoirs for cross-contamination. This hypothesis was not been proven by this work; the results showing that biofilms were not present and that adequate hygiene of these surfaces instead depends on the ability to remove all meat-based residues from them at the completion of each day's processing.
For premises operating interlocking belts from one manufacturer (Intraloxreg), a clean-in-place system is now available that is able to achieve this. Premises operating conventional disinfectant and water sanitisation of either continuous or interlocking belts must ensure that meat residue is completely removed before disinfection.
The majority of New Zealand meat industry premises can now demonstrate that their hygienic processes in this area are under control. 
The microbiota of conveyor belting in this study was found to consist of bacteria from five taxonomic groups; the Flavobacteriaceae, the Actinomycetales, the Bacillus/Clostridium group, and the alpha and gamma branches of the Proteobacteria. The genera present on belts from premises whose hygiene was found to be in control did not contain species known to cause food-borne disease or spoilage of vacuum packaged meats.
The bacterial viable count remains the most effective method available at this time for monitoring conveyor belt hygiene. Attempts to develop a monitoring system based on microscopy of an in-situ sampling device were unsuccessful due to an inability to penetrate the meat residue matrix. Denaturing Gradient Gel Electrophoresis (DGGE) may offer an alternative for rapid investigation of diversity, but further work is required before this can be validated for routine use.

year: 2007

title: Place responsive and culturally responsive outdoor education in secondary schools: Examining teachers' perspectives and experiences

authors: Skipworth, Andrew James

subjects: place responsive

abstract: Sustainability, place and human connectedness have increasingly become the focus of research and professional dialogue in school-based outdoor education in Aotearoa New Zealand. These developments challenge traditional practices that privilege adventure and individualistic outcomes in outdoor education. At the same time, the implementation of culturally responsive practices within many secondary schools has further challenged teachers of outdoor education to ensure that pedagogical approaches and outcomes meet the needs of their diverse student population. An increasing number of educators appear to have adopted place responsive and culturally responsive pedagogies within their outdoor education programmes or units of work at the senior school level, yet there is limited research examining teachers’ perceptions and experiences in doing so.
Adopting an interpretive framework, and using qualitative research methods, this research focuses on the challenges faced and opportunities presented when secondary school teachers in Aotearoa New Zealand adopt place and culturally responsive pedagogies in outdoor education. Six teachers of senior level outdoor education from schools spread throughout Aotearoa New Zealand shared their stories. An inductive analysis of the interviews identified these teachers faced ongoing challenges with adopting new pedagogies in outdoor education, which was in part because many colleagues held perceptions that outdoor education was less important than other subjects and was primarily about having fun. In addition, the complexities of assessment at the senior level meant that teachers often faced challenges in formally assessing student learning. Teachers also found that undertaking change required shifts in mind-set which were further supported by targeted professional development, engagement in post-graduate study and talking with like-minded teachers. However, teachers’ adoption of place and culturally responsive approaches generated notable opportunities to align to the front end of the New Zealand curriculum, promote the holistic development of students and nurture cultural diversity.
This study highlights that undertaking curriculum and pedagogical change in outdoor education in secondary schools is a complex process, which is greatly influenced by the attitudes and perceptions of others. The potential alignment of place responsive and culturally responsive pedagogies became apparent, as did the need for more targeted professional development for teachers of outdoor education. Teachers’ adoption of these pedagogies also highlighted a greater capacity for authentic outdoor education experiences for students that also strengthened a commitment to their bicultural partnerships in schools. As the nature of education changes in schools, contemporary pedagogies in outdoor education have the potential to enhance the capacity of schools to facilitate learning that will meet the diverse needs of learners in Aotearoa New Zealand.

text: Place responsive and culturally responsive outdoor education in secondary schools: Examining teachers' perspectives and experiences Sustainability, place and human connectedness have increasingly become the focus of research and professional dialogue in school-based outdoor education in Aotearoa New Zealand. These developments challenge traditional practices that privilege adventure and individualistic outcomes in outdoor education. At the same time, the implementation of culturally responsive practices within many secondary schools has further challenged teachers of outdoor education to ensure that pedagogical approaches and outcomes meet the needs of their diverse student population. An increasing number of educators appear to have adopted place responsive and culturally responsive pedagogies within their outdoor education programmes or units of work at the senior school level, yet there is limited research examining teachers’ perceptions and experiences in doing so.
Adopting an interpretive framework, and using qualitative research methods, this research focuses on the challenges faced and opportunities presented when secondary school teachers in Aotearoa New Zealand adopt place and culturally responsive pedagogies in outdoor education. Six teachers of senior level outdoor education from schools spread throughout Aotearoa New Zealand shared their stories. An inductive analysis of the interviews identified these teachers faced ongoing challenges with adopting new pedagogies in outdoor education, which was in part because many colleagues held perceptions that outdoor education was less important than other subjects and was primarily about having fun. In addition, the complexities of assessment at the senior level meant that teachers often faced challenges in formally assessing student learning. Teachers also found that undertaking change required shifts in mind-set which were further supported by targeted professional development, engagement in post-graduate study and talking with like-minded teachers. However, teachers’ adoption of place and culturally responsive approaches generated notable opportunities to align to the front end of the New Zealand curriculum, promote the holistic development of students and nurture cultural diversity.
This study highlights that undertaking curriculum and pedagogical change in outdoor education in secondary schools is a complex process, which is greatly influenced by the attitudes and perceptions of others. The potential alignment of place responsive and culturally responsive pedagogies became apparent, as did the need for more targeted professional development for teachers of outdoor education. Teachers’ adoption of these pedagogies also highlighted a greater capacity for authentic outdoor education experiences for students that also strengthened a commitment to their bicultural partnerships in schools. As the nature of education changes in schools, contemporary pedagogies in outdoor education have the potential to enhance the capacity of schools to facilitate learning that will meet the diverse needs of learners in Aotearoa New Zealand.

year: 2017