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September 07, 2020

Can New Zealand's COVID success assist trade?

Virus transmission in food processing and distribution can threaten food trade

Dealing with the COVID-19 pandemic, New Zealand has relied on health science, expertise and engaging the Team of 5 million. We have developed systems to successfully eliminate broad transmission, and securely control infections as they are identified.

New Zealanders have been provided with fiscal support at least in the interim, to staunch the haemorrhaging of incomes due to lockdowns and reduced business activity. International experience from the 2008-09 Global Financial Crisis (GFC) shows that New Zealand should not withdraw these supports prematurely.

There are a range of calls for a COVID recovery that creates a new economy, including revolution to a greener, more knowledge-based one with more resilience to future change.

This article looks at the science and expertise to ensure a sound base for New Zealand’s recovery by supplying our high value food to the world.

For our income and economic response, as with the health response, we should look to science and expertise which can provide a sound system for the future. Thinking as kaitiaki of our taonga, the ‘economy’ response could be based on three main taonga or resources and our world advantage. These three are our environment and ability to produce clean, green and high value food, our relatively unspoiled landscape and regenerating environment for relaxed, natural enjoyment, and our practical expertise to apply learned skills to new challenges.

This article looks at the science and expertise behind ensuring a sound future for supplying our high value food to the world. As with New Zealand’s participation in multilateral world health initiatives like vaccine development, we shall also contribute to world recovery.

The tricky virus which causes the COVID-19 illness makes hygienic food processing and distribution challenging.

Early infections in the recent COVID-19 outbreaks in Victoria, Australia and in Auckland were associated with meat plants and/or their cold storage facilities. Employees at Melbourne meat processor and exporter Cedar Meats began to contract COVID-19 in early April. By late July In Victoria there were over 300 cases linked to five workplaces processing and packing meat and poultry. In South Auckland an early case, possibly the index case, was in the household of a person working at a coolstore of the Americold company.

The problem

The role of food processing plants in spreading the virus therefore needs investigation. They have three main conditions which are particularly conducive to survival and transmission of the SARS-CoV-2 virus which causes the COVID-19 illness. These conditions are:

  • Large numbers of people in close proximity at work, at shift changes, and often using shared transport
  • The atmosphere is cool to maintain fresh food in the processing rooms, and close to freezing or below in the coolstores
  • Smooth stainless steel and polypropylene plastic (PP) surfaces on the equipment and walls, for cleanliness.

To mitigate the close proximity workers need to ‘socially distance’, wear face covering, exercise good hand hygiene. In addition, worker screening on entry and, where possible, physical barriers between workers may be required. All of these are testing but can be achieved.

We tend to think of germs as thriving in hot, humid and rough or ‘spongy’ environments. However, the SARS-CoV-2 virus survives at higher infection levels for longer at lower temperatures. In overseas research, the virus culture retained 50 percent of its infectious level for one day at a tropical 37 degrees celsius and for seven days at room temperature of 22 degrees celsius. But getting closer to food temperatures, at four degrees celsius the virus culture retained 90 percent of its infectious level after 14 days. In coolstores at chilled levels of zero to minus one degree celsius, or frozen coldstores at minus 18 degrees celsius we could expect the virus culture to retain high infectious levels for significantly longer than 14 days.

The rough, ‘spongy’ environments do not sustain SARS-CoV-2 virus either. The virus-contaminated surfaces are called fomites, and at room temperature, a ‘spongy’ paper fomite retains 50 percent of its infectious level for just 30 minutes, while a wood fomite retains 50 percent for one day. Unfortunately for our processing plants, a PP plastic fomite retains 40 percent of its infectious level after four days and a stainless steel fomite retains 60 percent after the same period. This science of the SARS-CoV-2 virus makes hygienic food processing and distribution challenging.

The world food consumers face the need for really strong evidence that it is still okay to bring chilled and frozen food from across the world.

Our success at producing clean, green, high value food to supply to the world is one of New Zealand’s main community and economy strengths. An important need for a sound base to New Zealand’s post-COVID-19 recovery is that the world food trade survives and flourishes.

The experience abroad

That may seem a given, but in some countries the reputation of the cold storage process, and particularly meat and poultry processing have taken a heavy hit as they have been closely associated with large clusters of COVID-19 cases. The New Zealand outbreak now known as the Auckland August cluster, and earlier in some way associated with the South Auckland Americold coldstore, has direct and indirect cases totalling 150 as at 3 September. This falls into perspective when compared with Victoria’s 300 cases linked to five meat and poultry work places.

In the US State of South Dakota by the end of May over 24 percent of the 6,500 workers in four beef, pork and poultry plants were infected with COVID-19.

Much more dramatic has been the US meat and poultry industry numbers collected from US States by the Centers for Disease Control and Prevention (CDC). These figures were first obtained in late April from 23 States, then by the end of May they were obtained from 29 of the 50 States.

  Late April End of May
Number of employee cases 4,900 17,350
Number of plants 115 264
Percent of employees 3.8% 9%
Employee deaths 20 91


By the end of May 17, 350 employees in 29 States had COVID-19. This was 9 percent of employees. 91 employees had died. The four plants in South Dakota recorded the highest average rate of COVID-19 cases with over 24 percent of employees. Another disturbing CDC finding is that while 61 percent of the employees identified by ethnicity were Hispanic, black or Asian, 87 percent of those with COVID-19 were Hispanic, black or Asian.

Americold is headquartered in Atlanta Georgia, a State in which the 14 poultry plants providing data employed 16,500 people and had 509 cases or 3.1 percent of employees to the end of May. Americold is valued at NZ$11.8 billion and owns and operates 183 sites in US, Canada, Australia, New Zealand and Argentina.

The challenge

Food consumers need really strong evidence that it is still okay to bring chilled and frozen food from across the world. This evidence would be very beneficial to both New Zealand and Americold. 

If the world food trade continues, New Zealand can sit in a high-value spot for as long as we have eliminated the domestic presence of COVID-19.

What we do not know is which food-related SARS-CoV-2 fomites will retain the virus under chilled and frozen temperatures, and for how long at each temperature. We get a rough indication if we extrapolate from the above findings. After eight weeks chilled to around freezing, the infectious level of the stainless steel fomite could still be as high as half of the infectious dose. The polypropylene fomite would be not much lower. We also need to know how long it may remain infectious on surfaces in refrigerated shipping containers carrying food.

Even more basic, we do not know for certain whether or not there can be actual transmission of SARS-CoV-2 virus from stainless steel and PP plastic fomites and other food fomites to infect humans with COVID-19.

We need that information to reassure our food customers. Then if the world food trade continues, New Zealand can sit in a high-value spot as long as we have SARS-CoV-2 contained. New Zealand will also be in a strong position to provide practical assistance and advice to other players along the world’s food value chain.