Back in 2006, New Zealand had the highest reported rates of Campylobacter infection in the developed world, with more than 13,000 notified cases of campylobacteriosis every year. But within two years, that number had dramatically dropped by over 50 per cent. Another concerted effort reduced foodborne cases a further 20 per cent over the five years to 2025.
Behind this turnaround was a collaborative effort from ESR scientists, New Zealand Food Safety, and other partners.
The risk assessment team at ESR are part of the reason food from Aotearoa New Zealand is well-regulated and generally considered safe. In the Campylobacter clean-up, ESR’s risk assessment team undertook risk modelling that informed regulatory and industry interventions. Their scientific evidence helped identify where to intervene in the poultry supply chain, assisting the coordinated actions that quickly decreased campylobacteriosis rates.
“Risk assessment is about understanding the probabilities and consequences of a particular food safety issue,” explains scientist Peter Cressey, who has been with ESR for 30 years. The team follows a systematic four-step process to identify hazards, understand if exposure causes harm, assess exposure levels, then calculate the probability of harm happening.
This risk assessment then informs how a risk is managed, enabling regulators to make informed decisions. “If the probability of an adverse effect is very, very low, then perhaps their resources are best put elsewhere. If it's high and the consequences are high, then there’s a need for immediate action,” says Cressey.
Interventions by New Zealand Food Safety need to be based on good evidence, says deputy director-general Vincent Arbuckle. “Science and research will always be central to this work.”
“Our work with ESR has played an important role in our success meeting our target to reduce campylobacteriosis rates by 20 per cent. ESR’s important work has helped us to identify the main foodborne sources of Campylobacter, develop new test methods, and track our progress towards the target.”
It’s not always about identifying danger. A big part of the ESR risk assessment team’s work is providing reassurance that risks are negligible. For example, about nine months after Cyclone Gabrielle in 2023, many Hawke’s Bay community members became concerned about the effect of breathing in dust, as massive quantities of deposited silt began to dry and was picked up by spring winds.
Commissioned by Health New Zealand | Te Whatu Ora National Public Health Service, ESR’s risk assessment team worked with NIWA and Hawke’s Bay public health officials to monitor the amount of dust in the air, and had it analysed for crystalline silica and other hazardous properties. They concluded the dust was a low respiratory health risk.
"People in the Hawkes Bay had a lot of things to worry about,” says Cressey. “One of those was, ‘What harm could come to me from exposure to all this silt?’ Our research concluded that while health effects may occur due to flooding events, this is most commonly due to direct contact with flood waters, rather than flood-deposited silt.”
Humans are wired to be naturally alert to hazards in our environment and food, says Cressey – but for Food Safety Week, his advice is to save yourself unnecessary anxiety about food health risks by checking that your information source is credible. “Look for trusted sources – is there evidence? NZFS, Food Standards Australia New Zealand, the World Health Organization and the Food and Agricultural Organization of the United Nations are credible sources of information on food safety,” he says.
When asked about the most dangerous thing in our food system, Cressey – who has spent 30 years identifying genuine risks – gives a surprising answer: "Not enjoying it. We're here to make the food supply as safe as possible. Food should be a pleasure.”
The team’s work has also been applied internationally. They were engaged by the World Food Programme, which provides food as aid, to identify the cause of food-related illness in Africa. The problem was identified as due to toxins in weed seeds harvested at the same time as food ingredients. ESR were part of a team that was able to establish a pragmatic limit for the toxins that would protect people, but wasn’t so stringent that people would starve due to food aid products being withdrawn.
Another reassurance was provided when the team looked at aflatoxins, a “seriously nasty” group of toxins produced by fungi that can occur in imported foods such as peanuts and spices, says Cressey. The ESR team defined the level of exposure in New Zealand, calculated the probabilities of that causing liver cancer, and concluded that risks were very low, likely responsible for only one liver cancer diagnosis every decade.
Climate change could bring more food safety risks to Aotearoa New Zealand. There are tangible indicators of change. We are now seeing seasonal outbreaks of shellfish-associated illness in the Bay of Plenty that used to be seen only in people who had been on holiday to warmer Pacific Islands. “As the temperature of our coastal waters increases, there is the potential for organisms that cause fish-based poisoning to establish on our coast,” says Cressey, and the same applies to the risk of establishment of fungal mycotoxins in our warming climate.