"It wasn't something that I planned to do, I hadn't actually thought about doing a PhD."
Focusing on the South African wine industry, Kelle's research found ethical certification often fails to address underlying sustainability and equality injustices.
"I wanted to understand the wine industry from a global perspective.
"South African wine producers have come under pressure to reassure customers their wine is ethical and there's been widespread growth in ethical certification labelling.
"I wanted to find out whether this growth in ethical labelling had addressed any unfairness or unethical practices in the industry."
Kelle spent nine months in South Africa carrying out her research, doing interviews, attending conferences and teaching as well as analysing quantitative data.
"I found some positives — for example, ethical certification has performed a regulatory role by enforcing basic labour standards throughout the industry.
"Some people I spoke to felt even though labour laws had been strengthened, not everybody was playing by the new rules, and ethical certifications have helped to address that."
However, Kelle said the ability of ethical certification to address issues in the South African wine industry is limited.
"Because of the entrenched networks of power, workers have not been able to take advantage of their rights to a meaningful degree.
"The most powerful voices still dominate the process of setting standards, as well as controlling access to training and education on certification.
"Ethical certifications generally didn't mean that more value was retained at the supply end of the chain, they actually helped the powerful retailers gain more."
Kelle is sceptical of how much ethical certification can influence global capitalism.
"Global production networks won't truly deliver fairness and sustainability by relying on consumer incentives.
"Consumers still need to do their homework.
"We shouldn't rely on an ethical label without knowing what that label means and whether it is independent and trustworthy.
"Unfortunately there's no easy way to do that, it means taking the time to read up on products, and not everyone has that luxury.
"In New Zealand, buying local products where possible is another way of reducing your contribution to trade injustice and environmental harm."
Since completing her studies, Kelle has moved into a role in Jacinda Ardern's office at Parliament as a researcher.
Moving from study to working at Parliament Kelle was nervous about going into a completely different environment that she wasn't used to but has found that a lot of the skills she gained doing her PhD are transferable.
"I guess I learnt discipline and how to just 'get it done'."
Note: Her thesis represents her own research findings only, and doesn't necessarily represent the views of the Prime Minister or the Government.
