By Dr Narelle Fegan and Dr Andrew Leis
Keeping our food safe
The recent outbreak of hepatitis A, which is thought to be associated with the consumption of frozen berries, has highlighted food safety concerns and sparked debates around country of origin labelling and testing of imported foods. Ensuring the safety of our food supply can be a complex process that involves maintaining good hygienic practices in the production and handling of foods at all stages between the farm and consumption.
With some foods, we can reduce the risk of foodborne illness through a heating process, which includes practices like cooking, canning and pasteurisation. However, with fresh produce (such as leafy green and fruits), a heating step is less desirable – we have to rely more on hygienic production to deliver a safe food product. There are quality assurance schemes in place to ensure that fresh produce is grown, harvested, packed and transported to limit contamination by foodborne pathogens.
These schemes rely on people involved in all parts of the production chain following the procedures outlined, to deliver a product that is safe to consume. Such quality assurance schemes operate across the globe and imported products are required to meet the same hygienic standards as food produced in the importing country.
Can testing of food ensure it is safe to eat?
Microbiological testing of foods is only one aspect of quality assurance schemes designed to help keep our food safe. Scientific evidence and history tells us that testing of products for pathogens is not an efficient way of determining if food has been contaminated.
This is particularly true of pathogens that occur very rarely in food (such as hepatitis A) as only a very small amount of the food will be contaminated, and we can’t guarantee we will sample the portion of food where contamination occurs. The difficulties associated with pathogen testing of foods include:
- Contamination is not evenly distributed within the food and only certain portions of the food may contain the pathogen.
- Testing for foodborne viruses destroys the portion of food that is tested.
- Because the food is destroyed during testing, not all of the food can be tested as there would be nothing left for us to eat. Only some of the food can be tested – but sampling plans have been developed to try and maximise the chances of detecting foodborne pathogens.
- Testing methods for foodborne viruses in particular can be difficult to perform, as we have to try and isolate viruses and their genetic material from foods which are often very complex in nature (containing fats, sugars and salts, which can all make it more difficult to detect pathogens).
For these reasons testing of food is only one part of quality assurance schemes, with more attention focusing on hygienic production to limit the opportunities of food becoming contaminated with pathogens.
Why would frozen berries be at risk of carrying hepatitis A?
Freezing is a highly effective and convenient way to increase the shelf-life of foods, and unlike heat-based sterilisation techniques, it preserves most of the nutritional value of the food (some components, like vitamins, are quickly destroyed by heat). Freezing not only prolongs shelf life but also allows us to enjoy very seasonal products, such as berries, at any time of the year.
Preservation of viruses and bacteria during freezing is affected by the rate of freezing and the amounts of sugars and other molecules nearby that help to slow the growth of ice crystals. In a household freezer, water freezes quite slowly – consider the time it takes to freeze water in ice cube trays. Slow freezing favours the formation of ice crystals. As the crystals grow in size, they can kill some bacteria and viruses. On the other hand, high local concentrations of sugars and other molecules can protect the microorganisms from damage.
Frozen berries are generally safe to eat, and have only occasionally been involved in foodborne outbreaks. Hepatitis A virus infection as a result of eating contaminated food (not just berries) is also very rare, particularly in Australia where on average only five cases a year are associated with food consumption in Australia. This is very small compared to other foodborne pathogens in Australia such as Norovirus, where an estimated 276,000 cases a year are associated with food and bacteria, or Campylobacter where 179,000 cases are associated with the consumption of food.
What can we do to ensure the food we eat is safe?
It is not possible to ensure safety by testing a final product. Therefore, systems based on hazard analysis and identification of critical control points have been developed and adopted by governments and food producers through food regulations, industry guidelines and quality assurance schemes. However, human error through poor planning or poor execution can lead to one or more failures along the supply chain. The best thing we can do to ensure the food we eat is safe is to foster a culture of food safety. This means better educating all those involved in the food industry, as well as governments and consumers, so that they understand the safety risks associated with the production, manufacture and consumption of foods.Food safety needs to be seen as an investment, not a cost.
For more information, visit our website.
Bill Gates caused a stir recently by drinking a glass of water that had, only five minutes earlier, been human waste.
No, Billionaire Bill hadn’t lost a dare. He was actually showcasing his faith in the latest wastewater processing technology – technology that could, if utilised properly, go a long way towards solving the global issue of access to clean drinking water.
Though, it’s not just drinking water that’s in the picture. Imagine, that instead of sipping from a glass of water, Bill was instead quaffing a Barossa Valley red, produced from a vineyard that uses wastewater to irrigate vineyards. It’s an entirely possible scenario (although we’re not sure how often Bill visits Tanunda).
For many, reconditioned wastewater is taboo for consumption, but as Bill so prominently demonstrated, wastewater processing technology is a viable way of both hydrating our planet AND reducing waste.
Which is why we’ve been working with some of Australia’s leading wineries to prove that wastewater can play an important role in wine production.
In a recently released report – Sustainable recycled winery water irrigation - we demonstrate how wineries could reuse their wastewater to safely irrigate their crops. Not only would the reuse of wastewater result in cost savings and better environmental practices, but it could even improve the quality and yield of the crops themselves.
Our lead scientist on the report, Dr Anu Kumar, and her team developed the guidelines after rigorous field, laboratory and glass house trials with participating wineries in the Barossa Valley, Riverina and McLaren Vale regions.
Anu and her team looked at the options for the reuse of wastewater on the vineyards – irrigation, evaporation and disposal – and found that, on the whole, irrigation was the most sustainable.
The study found that wastewater containing less than 60 mg per litre of sodium, 1250 mg per litre of potassium and 625+1084 mg per litre of sodium plus potassium (in combination) was safe for application on grapevines. Of particular interest, the nutrients and organic matter in winery wastewater can even enhance soil productivity, increasing crop growth and yield.
In fact, some of the participating wineries were so satisfied with the results that they have begun implementing our guidelines themselves.
But Anu and her team have been upfront in explaining this isn’t a one size fits all solution. For instance, wastewater can also increase soil salinity, which is bad news for healthy soil.
“It really isn’t a one-approach method,” said Anu. “Individual wineries need to discuss how they use wastewater with experts to ensure that guidelines are being adhered too, as well as the strict regulatory conditions.”
Dr. Kumar and her research team will continue to work with their partners at the University of Adelaide and the Australian Grape and Wine Authority (AGWA) to share these findings with other wineries around Australia.
In a country like Australia that is so susceptible to drought conditions and water shortages, it’s important that we find more efficient and sustainable ways to use what can be such a scarce resource.
Now, to get Bill down to the Barossa for that glass of red…
In conjunction with Dr Kumar and her team, the Australian Grape and Wine Authority has published a useful resource kit which includes more information about winery wastewater management and recycling.
By Leon Braun
“’Twas the night before Christmas, when all thro’ the house
Not a creature was stirring, not even a mouse …”
CSIRO scientists are keeping their eyes peeled for more than just Santa Claus this Christmas. With unusually high numbers of mouse sightings in Victoria this spring, CSIRO ecologist Peter Brown and colleagues at various Australian and New Zealand research agencies are monitoring mouse populations to see whether 2015 will bring a sigh of relief or send people scurrying for cover under a deluge of tiny, furry bodies.
While taken individually, mice can be rather cute (think Mickey, Mighty and Danger), en masse they can be absolutely devastating. In 1993, Australia’s worst ever mouse plague caused an estimated $96 million worth of damage, destroyed thousands of hectares of crops, blighted piggeries and ravaged poultry farms. The whiskered marauders chewed their way through rubber and electrical insulation, damaged farm vehicles, ruined cars and buildings. Another plague in 2010/11 was almost as bad, affecting 3 million ha of crops in NSW’s central west and the Riverina, as well as parts of Victoria and South Australia.
Along with economic hardship and disease, plagues bring severe psychological distress for people living through them.
“The sheer stress of dealing with mice in your kitchen every night takes its toll,” Peter says. “They’re everywhere: chewing, defecating, breeding.”
The good news is that with sufficient warning it is possible to prepare for mouse plagues, and to minimise the damage they cause, through early baiting and removing food supplies and cover. Over the years, our scientists have become increasingly accurate at predicting mouse plagues (they got it right in 1994 and 2001-2003) and have developed an ever more sophisticated range of tools to assist them. The latest weapon in their arsenal is “MouseAlert“, a citizen science website where keen-eyed rodent reporters can notify CSIRO about mouse sightings. The website is optimised for mobile phones, and Peter and his team hope to have an app out soon.
“Numbers are everything when you’re trying to predict a plague,” Peter says. “Traditionally we’ve used traps and chew cards [thin pieces of cardboard soaked in vegetable oil], but they have disadvantages, not least the fact that we’re not physically able to put them everywhere. MouseAlert allows us to capture data over a much wider area and potentially spot a plague well before it becomes a problem.”
Equally important as sightings, Peter says, are reports of where mice haven’t been.
“The jump from zero sightings to one or two can be an important indicator that mouse numbers are increasing,” he says. “By participating in citizen science, the public can help us identify these trigger points.”
So how are things looking this year? A little ominous, actually. Unusually high numbers of mice were seen in western Victoria in September. Depending on how much rain we get, they could build up to plague proportions by March or April next year. That’s why Peter wants mouse watchers to keep their eyes peeled:
“If it looks like there’s going to be a plague, we want to be able to give farmers plenty of time before sowing to prepare – or else put their minds at ease if it looks like there isn’t.”
So if you do see a mouse this Christmas Eve – stirring or not – get over to MouseAlert and report it. The pantry you’re saving could be your own!
Milk is a highly nutritious food, and an important source of amino acids and minerals such as phosphorus and calcium, which contributes to bone health.
Historically, milk was prone to contamination by bacteria from cows that could cause severe illness in humans. This remains the case with raw (unpasteurised) milk. The tragic death of a Victorian toddler this week is a stark reminder of these risks.
Pasteurisation involves heating the product to 72°C for 15 seconds. The method was originally employed to destroy bacteria in wine and beer that caused these products to spoil. It was quickly realised that this process could also be applied to milk to destroy harmful bacteria, and make milk safer for human consumption.
Pasteurisation was first introduced in Australia in the late 1950s and remains a legal requirement for milk produced for human consumption in Australia.
Nowadays, some of the important bacteria that pasteurisation targeted, such as those that cause tuberculosis, are no longer as problematic. So why do we continue to pasteurise milk?
The animals we use for milking can sometimes carry other pathogenic organisms that are capable of causing disease in humans. They can be found on hides or shed in the faeces.
Even healthy animals may be a source of organisms that are harmful to people. Such pathogens may be present in the farm environment, including soil, water, on pasture and in animal feeds. These pathogens can enter the milk during milking and if such milk is consumed, it can cause disease.
The most common pathogens found in association with dairy farms and milking animals include bacteria such as Escherichia coli (E. coli), Campylobacter and Salmonella, but other pathogens such as parasites like Cryptosporidium, a type of gastro, may also be present.
Campylobacter and Salmonella can cause severe diarrhoea and certain types of E. coli, particularly those known as Shiga toxin-producing E. coli (STEC), can cause very severe disease which impairs kidney function and may result in death.
Milk is highly nutritious to bacteria. Bacteria can quickly proliferate if their growth is not inhibited. Stopping the growth of bacteria in milk requires either heating to kill the bacteria, or chilling, which will not kill the bacteria but will slow down their growth.
E. coli, for instance, can go from ten cells to 100 million cells in just over six hours at 30°C. Only ten cells may be required to make someone ill. If such an organism is likely to be present, it’s important that any potential growth is stopped.
These harmful bacteria have caused outbreaks and disease associated with the consumption of raw milk in many countries. Data from the United States indicates that over a 13 year period to 2011, there were 2,384 illnesses, 284 hospitalisations and two deaths associated with the consumption of raw milk.
In Australia, raw milk contaminated by bacteria such as Campylobacter and Salmonella caused at least nine outbreaks of disease between 1997 and 2008, leading to 117 cases of illness.
So why do people choose to drink raw milk?
Advocates of raw milk often claim improved health benefit and nutritional value, or desiring a product which has not undergone further processing, retaining bacteria naturally present in milk.
But there is no evidence that the health benefits of milk are compromised by pasteurisation.
The defining difference between pasteurised and raw milk is the bacteria that are present. As soon as milk is secreted from the udder, it is at risk of contamination by many different bacteria as it makes its journey to our table. This includes harmful bacteria. These bacteria can lead to severe illness in humans, particularly children and the elderly.
For these reasons, raw milk continues to have a far higher risk of causing illness. Pasteurisation remains an important step in ensuring we can continue to enjoy safer, nutritious milk.
Further reading: Bath milk crisis must prompt better cosmetic safety regulation
By Leon Braun
It’s downtrodden, underfoot and often under appreciated, yet so crucial to our existence that one of our scientists describes it as “the complex natural medium that supports all life on Earth”. It holds our crops, stores and purifies our water, and provides habitat for amazing creatures like the giant Gippsland earthworm, which can reach up to 3 m in length. But most of us only think about it when we’re trying to get it out of footy socks on laundry day.
It’s soil – and today (and all next year) it gets a bit of long-overdue recognition. December 5 is World Soil Day, and the United Nations has declared 2015 to be International Year of Soils. That’s a good thing, because globally, soils are under threat: from erosion, poor land management and urbanisation. At the same time, we need soils more than ever to produce the food we need for a growing population, to help manage climate change and to ensure ecosystem health.
Luckily for Australia’s soils, they have CSIRO looking out for them. We started researching soils in 1929, published the first soil map of Australia in 1944, and have been working hard ever since to improve our understanding and management of soils. We’re looking at ways to make agricultural soils more productive and to ensure they’re used sustainably, so future generations can continue to reap their bounty. And we’re working internationally too, so it’s not just Australia that benefits.
Our latest achievement (with allies from around the country) is the Soil and Landscape Grid of Australia, a digital map of Australia’s soils with two billion ‘pixels’ of about 90 by 90 metres, down to a depth of two metres below the surface. It contains information such as water holding capacity, nutrients and clay, and has applications for everyone from farmers deciding where to plant their crops to conservationists looking for habitats for endangered native species. You can read more about it here.
We’re also home to the Australian National Soil Archive, which has just gotten a new home in Canberra. The archive contains about 70,000 samples from almost 10,000 sites across Australia, the oldest dating back to 1924. Each sample represents a time capsule of the Australian landscape at the time it was collected, so we can measure things like caesium dispersal from the British nuclear tests at Maralinga and the impact of phosphate-based fertilisers on agricultural land. The archive is a vital national asset for soil researchers and industry, and has even been used by the Australian Federal Police to examine the potential of new forensic methods. Finally, data from the archive powers our first official app, SoilMapp, which puts information about Australian soils at your fingertips. This is incredibly useful, whether you’re growing canola on a farm in Western Australia or planning a major roads project in Victoria.
So as you go through your day today, eat your lunch, wipe your shoes, just remember: it takes 2000 years to form 10 centimetres of fertile soil suitable for growing our food, but just moments for that soil to blow away or get covered in a layer of asphalt. Something to think about next time you sit down to a meal – or do your laundry.
New technology to tackle biosecurity challenges down the track is one of the five megatrends identified in today’s CSIRO report Australia’s Biosecurity Future: preparing for future biological challenges.
As manpower in the agriculture and biosecurity sectors declines, we must look to technological innovation to protect crops. Monitoring and surveillance, genetics, communication and data analysis have been identified in today’s report as future work priorities, along with developing smaller, smarter, user-friendly devices.
But this is easier said than done. There are a number of potential barriers that need to be addressed to make sure that appropriate technologies are used to maximum effect. It might sound obvious, but making sure farmers can – and want to – use new technology is a crucial step.
With an ageing population and fewer young people entering agriculture, we are seeing the loss of the wealth of knowledge and experience held by long-time farmers.
Many farmers have a deep understanding of the day-to-day activities that can protect properties and reduce the spread of pests and diseases across the country, and this on-farm biosecurity knowledge may be lost.
We are also seeing a decline in specialists in areas crucial to biosecurity management such as taxonomy, plant pathology and entomology. This is prevalent throughout the biosecurity landscape, reducing our overall pest and disease response capability.
With fewer people training in taxonomy, we’ve estimated that 50% of Australia’s diagnostics capability will be lost by 2028.
Without adequate surveillance in place, pests can cripple emerging industries. In recent seasons, we have seen two new diseases devastate local farmers in the Northern Territory:
- the recent invasion of banana freckle, which authorities are working to eradicate
- the cucumber green mottle mosaic virus (CGMMV) infected melon crops near Katherine this year. Lack of CGMMV knowledge meant a delay identifying the disease and starting treatment.
Surveillance is critical to the delivery of effective biosecurity, both for early detection of a disease and for effective response. Yet delivery of effective surveillance faces a growing challenge which becomes greater in the more remote parts of Australia.
Constraints on surveillance include declining investment among jurisdictions, declining expertise or limited availability of personnel, expense and occupational health and safety requirements.
In response to these challenges there is a strong drive to draw on technological innovation to deliver biosecurity previously provided by people.
Research is already underway with new applications of technology for surveillance and detection, sensitive diagnostics, as well as preventative pre-border technologies.
Access to low-cost sensors and development of automated systems are opening up opportunities for rapid identification and response to pests and diseases. Sensors smaller than a pea can, for example, help monitor the health of oysters in real time.
Pestpoint, a mobile device application being developed by staff of the Plant Biosecurity Cooperative Research Centre (PBCRC) provides access to an online community of people working in the agricultural sector who need to identify plant pests in order to make decisions about how to manage those pests.
By using genetic techniques, scientists with the PBCRC are developing rapid tests using molecular sequences for identifying pests and diseases. The next phase is to transfer these tools to biosecurity practitioners, including diagnosticians and port inspectors.
Sounds great … but there are barriers
The adoption of a new technology hinges on how easily it can be incorporated into the existing biosecurity system, which means that the technology needs to be integrated into a human system:
- the connection to institutional arrangements governing biosecurity regulation, response and compliance
- the social acceptability of deploying smart technologies and information systems.
The Queensland Biosecurity Strategy: 2009–14 highlighted that biosecurity risks are inherently social, and that a better understanding of human behaviours, values and attitudes has the ability to improve engagement.
Similarly, the 2007 New Zealand Biosecurity Science Strategy indicated that the application of social research could increase biosecurity compliance and reporting, and support post-border invasion response programs.
Farmers and indigenous communities in remote and regional Australia are currently working together on a project to understand how each group decides to manage plant pests and diseases, and to increase their capacity to engage in biosecurity surveillance activities.
In the face of declining resources and investment, science and technology offer opportunities to create greater efficiencies in biosecurity while at the same time driving competitive advantage in primary industries.
Paul De Barro receives funding from the Bill and Melinda Gates Foundation and the Cotton Research and Development Corporation.
Grant Smith is a co-PI on the PBCRC bacterial diagnostics project described in this article. He is a member of various organisations including Australasian Plant Pathology Society (APPS), the Royal Society of New Zealand (MRSNZ) and the Project Management Institute (PMI).
By Gary Fitt, CSIRO
A nationwide outbreak of foot and mouth disease; an invasion of a devastating wheat disease; our honeybees completely wiped out. These are just three possible disastrous scenarios facing Australia; they’re considered in the Australia’s Biosecurity Future report published today by CSIRO and its partners.
Intensifying and expanding agriculture, biodiversity loss, and more people and goods moving around the world are the “megatrends” driving what we have called “megashocks” — new outbreaks of diseases and pests.
These three events alone could not only cost Australia’s economy billions of dollars, but would also devastate our agricultural industries and environment and severely alter our way of life.
How well prepared is Australia, and how would our biosecurity system cope with such a situation?
For example, governments and farmers near Katherine in the Northern Territory are mounting an emergency response to deal with an outbreak of a new disease — Cucumber Green Mottle Mosaic Virus — and while this virus is not likely to create headlines, it is devastating crops, severely affecting the NT farming community financially and threatening industries elsewhere in Australia.
An ever-hungrier world
As part of the drive to help feed the world, Australia will have to increase agricultural production — both through intensification and expansion. Both of these processes could expose new biosecurity challenges.
The United Nations Food and Agriculture Organization (FAO) has forecast that food production will need to increase by 60% (compared to 2005/2007 levels) to meet demand in 2050.
This 2050 scenario could see the value of Australian food exports increasing by 140% compared to 2007 levels.
However, Australia’s agriculture sector is already constrained by limited soil and water resources and future intensification will bring its own challenges through herbicide resistance and more intensive animal production systems. These factors could all increase the impacts of a biosecurity incident, and reduce the industry’s ability to sustainably meet demand.
In 1973 Australia’s wheat production industry was devastated by an outbreak of wheat stem rust, causing an estimated A$200-300 million in damages. While wheat stem rust has been under control since that time, there are new threats on the horizon.
Currently sweeping the world is the even more virulent Ug99, and without stepping up our biosecurity, it is likely to reach Australia. Luckily in this case we have time to prepare by developing varieties resistant to Ug99, but we may not always have such forewarning.
Expanding into new areas
Intensifying food production alone may not be sufficient to meet global demand. We may also have to expand into new or previously marginal areas. This could expose agriculture to new biosecurity threats, some that we may not fully understand, through new pathways or new hosts for pests and diseases.
For example, there is considerable government and industry interest in increased agricultural development in Northern Australia. Various reports, including the recent Green Paper on Developing Northern Australia suggest that northern agricultural production could increase substantially through targeted use of soil and water resources.
But this could expose Australia to new biosecurity threats. There are already a number of established pests and diseases in NT. And, importantly, these small areas of northern irrigated agriculture could act as a target for exotic pests and as a bridge for exotic pests to enter, establish and spread southwards.
This could have more severe consequences for established agricultural systems in southern Australia. In 1998 sugarcane smut appeared in the Ord, Western Australia. It then spread to Queensland in 2006, ultimately costing a 10-30% reduction in gross margins thanks to loss of yield, and the cost of planting resistant sugarcane varieties.
So biosecurity needs to be explicitly considered in any plan to expand agriculture in northern Australia – we need to anticipate future threats and mitigate them where possible.
Invasive species are one of the most significant known threats to biodiversity and ecosystem services around the world. In Australia invasive vertebrates such as rabbits, feral cats, pigs and camels impose severe impacts on Australian habitats and wildlife.
But biodiversity is also important in underpinning the ecosystem services for agriculture and the economy. Healthy soil function, pollination, and natural pest control are all driven by biodiversity within agricultural landscapes. Over the past century, crops have lost 75% of their genetic diversity, making them potentially more susceptible to new pathogens or pests.
We rely on some species for the services they provide, such as the European honeybees which pollinate our largely non-indigenous crops. Australia is fortunate to be the only continent not yet affected by the devastating bee pest, varroa mite. There is very real potential for it to arrive and spread in Australia.
Elsewhere in the world, varroa mite is driving a complex of factors leading to a global decline of honeybees, and native pollinators are also threatened through pesticide use and habitat loss.
Losing these pollination services, would severely impact the 30% of food crops which are dependent on honeybees, particularly many fruits and vegetables. The impact on our economy would be in the order of A$4-6 billion each year.
On the move
The increased movement of people, goods and vessels around the globe increases the chance of biosecurity threats hitting our shores. That’s why our biosecurity border protection is so important.
Inadvertent spread of exotic organisms in shipping containers such as European house borer in Western Australia, on contaminated equipment or carried by people such as the introduction of fire ants, as well as the spectra of deliberate introductions which haven’t yet happened in Australia show the scale and breadth of the issues we have to deal with.
An outbreak of an exotic pest or disease, such as foot and mouth disease (FMD) in Australia, which affects cloven hoofed animals such as cattle, pigs and sheep, could close down export markets overnight or make other countries more competitive.
An FMD outbreak in Australia could lead to industry-wide revenue losses for livestock producers of around A$6 billion for a small outbreak and A$50 billion for a large multi-state outbreak over a 10-year period. Additional costs related to disease control, such as labour, decontamination, slaughter, disposal and facilities, would be expected to range from A$60 million to A$373 million.
Pre-empting the threat
As an island nation, Australia has been able to maintain an enviable biosecurity status, keeping out many of the world’s worst pests and diseases. This means we have market access for a vast array of export produce, a status which will be increasingly valuable in a growing and highly competitive global market for food.
To ensure we maintain this status, the management of Australia’s biosecurity will require a step change towards smarter and more efficient strategies that are ideally ahead of the pace of change around the world. Smarter technologies, strengthened integration across governments and industry and great commitment will be needed. If we do this, we are surely better able to protect our farmers, communities and environment from the impacts of exotic pests and diseases.
Clearly, we can’t afford to become complacent with our nation’s biosecurity measures. As is true of any threat, it is much better to pre-empt and avoid than have to deal with the costly consequences.
The CSIRO Biosecurity Flagship receives funding from government and industry R&D bodies and works in collaboration with many research and industry partners..