AgResearch is a partner in the New Zealand Food Safety Science & Research Centre (NZFSSRC). The Centre is the focal point for food safety science in New Zealand. Current NZFSSRC Industry Members include organisations from the dairy, meat, poultry, seafood and horticulture sectors, and together provide access to world-class, industry-focused research capability in food safety. Below you can read about some of the research AgResearch has conducted with our partners and the NZFSSRC, including an economic evaluation of the industry body. 

Our research

Infectious pathogens originating from animals are a major concern for New Zealand’s food supply, water quality and agricultural exports. In the domestic food supply alone, cases of food-borne diseases are estimated to exceed 100,000 annually, with a direct cost of around $225m.

Many pathogens have a zoonotic origin, in other words they ultimately link back to farm animals. Significant pathogens for the pastoral sector include Campylobacter, Salmonella and Shiga toxin-producing E. coli (STEC).

AgResearch's food system integrity team runs a longstanding programme on infectious zoonosis, using a holistic approach that considers the animal host, the bacteria and the environment, and tackling the diseases from a multidisciplinary, One Health perspective. The research has strong connections to the broader food safety research and management system in New Zealand.

The problem

STEC are a group of bacteria associated with foodborne diseases and pose significant health risks to humans. Over the past ten years, New Zealand has reported an increase in hospitalisation associated with STEC infections in humans. In 2022, 1022 STEC cases were recorded (19.9 cases per 100,000 people). Cattle are a significant reservoir for human infections.

While E. coli  serotype 0157 is the most well-known of the distinguishable micro-organisms, other STEC strains have been increasing in prevalence.

Dairy production and consumer safety

Cattle herds are asymptomatic reservoirs for both O157: H7 and non-O157 STEC, and transmission to humans can be by consumption of food products or water contaminated with cattle faeces (Mathusa et al. 2010). The United States Department of Agriculture has declared O157:H7 and STEC O26, O103, O45, O145, O121 and O111 (collegially called Top 7 STEC) to be food adulterants. They are not permitted on meat to be imported into the US. 

In New Zealand, the dairy sector contributes significantly to the beef production, with c. 40% of the livestock processed at export plants and abattoirs comprising cull cows, heifers and young calves (Morris and Kenyon 2014; Beef and Lamb New Zealand 2016).

Beef and dairy farms are further connected through the supply of young (4–10 day old) and weaned (3–4 month-old) calves to beef farmers and the use of ‘beef’ land for ‘dairy’ activities such as winter grazing of dairy cows or rearing dairy heifer replacements. Currently, however, there is limited information available on the extent of the Top 7 STEC reservoir in New Zealand dairy herds to inform risk-assessment models for human consumption of beef products.


Industry impact for stakeholders

New Zealand Meat Processors use strict hygiene conditions and wash procedures to prevent contamination of red meat. These procedures are good at keeping the level of STEC contamination on the meat very low, but processors are always looking for ways to improve control and reduce the risk from STEC.

AgResearch has published findings of a study into the prevalence and virulence of Shiga toxin-producing Escherichia coli (STEC) strains in Waikato dairy farms. The study sought to gain insights into the incidence of E. coli serogroups, as well as the presence of virulence genes (stx1/2 and eae) in dairy farm effluent and calf faeces.    

AgResearch's study spanned two years and involved the collection and analysis of samples from cows, calves, and the farm environment of two pasture-based dairy farms in the Waikato region. The research sought to understand how Top7 STEC behave in different animals, how they move between animals, and what we can do to interrupt the chain of transmission. The presence of toxin genes stx and eae, as well as STEC7 bacteria, was evaluated to identify environmental reservoirs, intermediate hosts and key pathways that could drive the presence of Top 7 STEC in herds, utilising gene-based and traditional bacterial culture tests.

The research revealed that the frequency of STEC7 on the farms was generally low. STEC O26 was the most commonly detected STEC7, with its frequency in the animals and dispersion throughout the farm peaking in the summer. O157:H7, which was found less frequently was detected throughout year.

Fresh cow and calf faeces were identified as the primary source of STEC7, with these bacteria present in bedding material, pasture, soil, and trough water, making animals exposed to these materials susceptible to infection. Additionally, STEC7 was found to be transported by flies and birds, which were attracted to feed stores and effluent ponds on the farm.

The study's findings suggest that careful management of calf bedding and control of birds and flies, particularly in calf sheds and feed storage areas, could potentially reduce STEC spread on farms, and the research reaffirms that keeping calves away from paddocks recently grazed by adult cows or irrigated with farm effluent would decrease their exposure to STEC. The study also hinted that farm measures preventing weather stress in animals might also have a significant impact on STEC7 levels in animals leaving the farm, hence minimising the potential for cross-contamination of animals between transport and during processing.

The findings offer valuable insights into pathogenic bacteria's presence and movement within farms, supporting dairy farmers in enhancing biosecurity and animal health practices. These findings have been shared with DairyNZ, enabling them to provide improved recommendations to farmers for STEC7 and other pathogenic bacteria control on farms.

This research was jointly funded by MIA Innovation Limited and AgResearch.

Our SSI-funded science has enabled the application of whole-genome sequencing (WGS) coupled with bioinformatic algorithms to identify and provide deeper insights into epidemiological dynamics -sources, transmission and dispersion - of faecal bacteria along the farm-to-fork continuum.

Prevalence of Shiga toxin-producing Escherichia coli in pasture-based dairy herds

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Economic benefits of the NZFSSRC

The NZFSSRC is a national, virtual scientific network of New Zealand’s food safety researchers, hosted by Massey University and launched in 2016. The Centre synthesises input from industry, government, researchers and Māori to promote, coordinate and deliver food safety science and research for New Zealand. NZFSSRC is funded by government and industry.  In 2022, the NZFSSRC commissioned the Agribusiness and Economics Research Unit (AERU) at Lincoln University to quantify the value of the Centre’s work and its impact more broadly in New Zealand.  This study builds on a literature review of the benefits of food safety undertaken by Guenther et al. (2022) as part of this research. Research methods included interviews with participants from food industry and a desktop analysis. 

Economic valuation of the NZFSSRC

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Food Safety National Plan

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