title: Microbiological quality of Toroi:  A Māori food delicacy

authors: Dixon, Lorraine Louise

subjects: Maori

abstract: A study was undertaken to determine the food safety of the fermented Māori delicacy, Toroi.  Ten batches of Toroi were prepared by a commonly used traditional method that consisted of boiling the vegetable component, either watercress or puha, and combining it with chopped mussel flesh.  The mixture was cooled and then stored in a refrigerator for up to eight months to allow natural fermentation to take place.  All ingredients were sourced from retail outlets.  The Toroi was examined at intervals over eight months for a range of pathogens (seven in all) that have been related to incidents of food poisoning in ready-to-eat foods in New Zealand.  The survival of a faecal contamination indicator, the laboratory grown strain Escherichia coli NZRM 916, was mapped over eight months.  Two strategies to prevent the growth of Listeria monocytogenes in Toroi were also investigated.  

Only one of the seven pathogens sought was recovered from any sample.  This pathogen was Bacillus cereus, a spore-former known to be associated with vegetables.  All batches contained B. cereus on the day of preparation but after two weeks refrigerated storage there was no further recovery from any sample.  There was a very low incidence of natural E. coli in the Toroi, consistent with levels permitted in mussels sold in retail outlets.  The laboratory grown strain, E. coli declined substantially over two months and was not recovered from any samples at eight months.  
A laboratory grown strain of Listeria monocytogenes, (L70) was added to Toroi and grew well with an increase in concentration of about seven-fold, over 19 days storage in a refrigerator.  A bacteriocin producing lactic acid bacterium, Lactobacillus sake Lb706, was added in combined culture with L. monocytogenes to Toroi.  It was found that at least 5 x108 L. sake cells were required as an inoculum to ensure elimination of L. monocytogenes from the Toroi.  When a purified bacteriocin; nisin, was added, a concentration of 10 mg g-1 in the Toroi was required to eliminate L. monocytogenes.  The inhibition study results suggest that unacceptably high inocula or purified bacteriocin would be required to prevent the growth of L. monocytogenes in Toroi.

The results of this suggest that Toroi be prepared from mussels either purchased from a retail outlet or harvested from sites known to be free from contamination.  Toroi should be safe to eat if prepared carefully, chilled promptly and thoroughly and allowed to ferment for at least two weeks.  In addition, care should be taken to maintain Toroi at refrigerated temperatures until it is eaten.

text: Microbiological quality of Toroi:  A Māori food delicacy A study was undertaken to determine the food safety of the fermented Māori delicacy, Toroi.  Ten batches of Toroi were prepared by a commonly used traditional method that consisted of boiling the vegetable component, either watercress or puha, and combining it with chopped mussel flesh.  The mixture was cooled and then stored in a refrigerator for up to eight months to allow natural fermentation to take place.  All ingredients were sourced from retail outlets.  The Toroi was examined at intervals over eight months for a range of pathogens (seven in all) that have been related to incidents of food poisoning in ready-to-eat foods in New Zealand.  The survival of a faecal contamination indicator, the laboratory grown strain Escherichia coli NZRM 916, was mapped over eight months.  Two strategies to prevent the growth of Listeria monocytogenes in Toroi were also investigated.  

Only one of the seven pathogens sought was recovered from any sample.  This pathogen was Bacillus cereus, a spore-former known to be associated with vegetables.  All batches contained B. cereus on the day of preparation but after two weeks refrigerated storage there was no further recovery from any sample.  There was a very low incidence of natural E. coli in the Toroi, consistent with levels permitted in mussels sold in retail outlets.  The laboratory grown strain, E. coli declined substantially over two months and was not recovered from any samples at eight months.  
A laboratory grown strain of Listeria monocytogenes, (L70) was added to Toroi and grew well with an increase in concentration of about seven-fold, over 19 days storage in a refrigerator.  A bacteriocin producing lactic acid bacterium, Lactobacillus sake Lb706, was added in combined culture with L. monocytogenes to Toroi.  It was found that at least 5 x108 L. sake cells were required as an inoculum to ensure elimination of L. monocytogenes from the Toroi.  When a purified bacteriocin; nisin, was added, a concentration of 10 mg g-1 in the Toroi was required to eliminate L. monocytogenes.  The inhibition study results suggest that unacceptably high inocula or purified bacteriocin would be required to prevent the growth of L. monocytogenes in Toroi.

The results of this suggest that Toroi be prepared from mussels either purchased from a retail outlet or harvested from sites known to be free from contamination.  Toroi should be safe to eat if prepared carefully, chilled promptly and thoroughly and allowed to ferment for at least two weeks.  In addition, care should be taken to maintain Toroi at refrigerated temperatures until it is eaten.

year: 2007

title: Heritage-making in Aotearoa planning: Unsettling norms in contested urban space

authors: Hill, Carolyn Joy

subjects: Authorised heritage discourse

abstract: Heritage is currently a high-profile and often contentious topic in urban environments. As cities face growing challenges of climate change, intensification needs and cultural contestation, state-mandated heritage continues to have a significant influence on how cities are perceived, whose pasts are remembered, and what future change can be. However, this is being increasingly tested as urban pressures bring questions of who has a right to the city to the fore. 
Situated within the field of critical heritage studies, this thesis critically examines how heritage is officially “made” in the cities of Aotearoa New Zealand, and how emerging views and values may reshape these established norms for more spatially and culturally just futures. Focused on urban locations within the so-called “CANZUS” states (Canada, Australia, New Zealand and the United States of America (USA)), the thesis centres on statutory heritage – the objects and places that are identified and managed within state-mandated planning systems that create dominant assumptions about what is worthy of protection. As such, its contribution is at the intersection of heritage and planning as it critically queries heritage’s future legacy claims and considers what other legacies may be imagined. 
The thesis includes four key enquiries. First, it explores the history of state-led heritage-making in Aotearoa, focusing on the city of Tāmaki Makaurau / Auckland. It examines the tension between contemporary urban intensification priorities and heritage / special character regulation, critiquing the narrative of heritage as a “public good” given its entanglement with spatial and cultural inequity. Second, it studies three cases of urban heritage protest across Australia, Aotearoa and the USA. These cases expose the continued inadequacy of statutory heritage-making for Indigenous and emerging aspirations, as normative approaches are embedded not only by the heritage sector itself but by the planning and legislation systems that structure its mandate. 
Third, the thesis explores the current thinking of those shaping and working within heritage’s statutory framing across Aotearoa. It finds that heritage policy leaders are cognisant of, and concerned to change, heritage’s entrenched Eurocentricity, expert dominance and material orientation, but that shifting established practice remains a multi-dimensional challenge. Finally, it investigates the perspectives of young emerging planners in the city of Kirikiriroa / Hamilton, which again foregrounds the obstacles to displacing systemic norms but also highlights planning policy’s significant potential to shape different heritage futures. 
This thesis has important implications both for Aotearoa’s urban environments and for CANZUS cities more broadly. Grounded in contemporary real-world examples, it not only exposes heritage’s imbrication with issues of urban inequity but its deeper role in maintaining settler state security, making “home” on Indigenous land. It finds that unpicking this legacy will involve more than adding the heritages of “others” into the existing canon. Rather, deeper reconsideration of heritage’s societal purpose as part of Indigenous, multi-storied and dynamic cities is required. Finally, it highlights the central role for planning in transforming the heritage field, both through statutory policy reform and through integration with broader urban objectives. However, planners will need to be better equipped for critical engagement with heritage if they are to creatively support more inclusive, democratic and malleable alternatives.

text: Heritage-making in Aotearoa planning: Unsettling norms in contested urban space Heritage is currently a high-profile and often contentious topic in urban environments. As cities face growing challenges of climate change, intensification needs and cultural contestation, state-mandated heritage continues to have a significant influence on how cities are perceived, whose pasts are remembered, and what future change can be. However, this is being increasingly tested as urban pressures bring questions of who has a right to the city to the fore. 
Situated within the field of critical heritage studies, this thesis critically examines how heritage is officially “made” in the cities of Aotearoa New Zealand, and how emerging views and values may reshape these established norms for more spatially and culturally just futures. Focused on urban locations within the so-called “CANZUS” states (Canada, Australia, New Zealand and the United States of America (USA)), the thesis centres on statutory heritage – the objects and places that are identified and managed within state-mandated planning systems that create dominant assumptions about what is worthy of protection. As such, its contribution is at the intersection of heritage and planning as it critically queries heritage’s future legacy claims and considers what other legacies may be imagined. 
The thesis includes four key enquiries. First, it explores the history of state-led heritage-making in Aotearoa, focusing on the city of Tāmaki Makaurau / Auckland. It examines the tension between contemporary urban intensification priorities and heritage / special character regulation, critiquing the narrative of heritage as a “public good” given its entanglement with spatial and cultural inequity. Second, it studies three cases of urban heritage protest across Australia, Aotearoa and the USA. These cases expose the continued inadequacy of statutory heritage-making for Indigenous and emerging aspirations, as normative approaches are embedded not only by the heritage sector itself but by the planning and legislation systems that structure its mandate. 
Third, the thesis explores the current thinking of those shaping and working within heritage’s statutory framing across Aotearoa. It finds that heritage policy leaders are cognisant of, and concerned to change, heritage’s entrenched Eurocentricity, expert dominance and material orientation, but that shifting established practice remains a multi-dimensional challenge. Finally, it investigates the perspectives of young emerging planners in the city of Kirikiriroa / Hamilton, which again foregrounds the obstacles to displacing systemic norms but also highlights planning policy’s significant potential to shape different heritage futures. 
This thesis has important implications both for Aotearoa’s urban environments and for CANZUS cities more broadly. Grounded in contemporary real-world examples, it not only exposes heritage’s imbrication with issues of urban inequity but its deeper role in maintaining settler state security, making “home” on Indigenous land. It finds that unpicking this legacy will involve more than adding the heritages of “others” into the existing canon. Rather, deeper reconsideration of heritage’s societal purpose as part of Indigenous, multi-storied and dynamic cities is required. Finally, it highlights the central role for planning in transforming the heritage field, both through statutory policy reform and through integration with broader urban objectives. However, planners will need to be better equipped for critical engagement with heritage if they are to creatively support more inclusive, democratic and malleable alternatives.

year: 2024-12-16

title: Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture

authors: Watkins, Natalie Lisa

subjects: denitrification

abstract: The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD ha⁻¹, with a total annual application of 33 kg ha⁻¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 ± 3 days (mean and standard deviation).

text: Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD ha⁻¹, with a total annual application of 33 kg ha⁻¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 ± 3 days (mean and standard deviation).

year: 2013