tag:theconversation.com,2011:/es/topics/bacterial-contamination-14033/articlesBacterial contamination – The Conversation2023-06-05T01:32:27Ztag:theconversation.com,2011:article/1996682023-06-05T01:32:27Z2023-06-05T01:32:27ZTreated wastewater in Victoria is still contaminated, study finds. So are we and the environment safe?<figure><img src="https://images.theconversation.com/files/515024/original/file-20230313-24-48y9sf.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6000%2C3988&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Wastewater is a by-product of humanity produced all day, every day. At home, wastewater is the <a href="https://environment.des.qld.gov.au/management/water/pollution/wastewater">used water</a> that disappears when you flush the toilet, empty the sink or drain the washing machine. </p>
<p>Industrial processes also produce wastewater. Around the world, <a href="https://www.sciencedaily.com/releases/2021/02/210208085457.htm">359 billion cubic metres of wastewater</a> is produced each year – equal to 144 million Olympic-sized swimming pools. </p>
<p>In Australia, some of this water is treated and reused. This so-called “recycled” water is used, for example, to wash cars, water crops and gardens. Treated water is also released back into rivers as “discharge”, which is regulated under an operator’s licence.</p>
<p>So is treated wastewater safe? Our <a href="https://www.epa.vic.gov.au/about-epa/publications/2054-2-emerging-contaminants-in-recycled-water">research</a>, published today, found wastewater treatment removes a lot of particles, but some contaminants remain. While it’s not enough to affect human health, effects on the environment are less clearly established.</p>
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Read more:
<a href="https://theconversation.com/we-now-treat-half-the-worlds-wastewater-and-we-can-make-inroads-into-the-other-half-154715">We now treat half the world's wastewater – and we can make inroads into the other half</a>
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<figure class="align-center ">
<img alt="Purple tap and hose for recycled water with sign saying it's not for drinking" src="https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/515026/original/file-20230313-447-cmkech.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Recycled water is commonly used to irrigate gardens and crops.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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</figure>
<h2>Making the most of our water</h2>
<p>Water is a precious, finite resource. There is no such things as “<a href="https://cosmosmagazine.com/history/age-of-water/">new</a>” water. Our planet’s water dates back <a href="https://arxiv.org/pdf/2212.05441.pdf">4.5 billion years</a> and is constantly recycled by Earth’s systems. </p>
<p>As Earth’s population grows and the climate dries, we need all the water we can get.</p>
<p>In light of this challenge, the state of Victoria has <a href="https://www.water.vic.gov.au/water-for-victoria">a plan</a> to better use treated wastewater. Other Australian states and territories have <a href="https://water.dpie.nsw.gov.au/plans-and-programs/nsw-water-strategy/the-strategy/our-water-our-future">similar</a> <a href="https://www.rdmw.qld.gov.au/water/how-it-works">plans</a>.</p>
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Read more:
<a href="https://theconversation.com/where-to-find-more-water-eight-unconventional-resources-to-tap-183681">Where to find more water: eight unconventional resources to tap</a>
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<p>Wastewater comes from homes, businesses, industrial sites and farms, as well as any stormwater or groundwater that enters the sewer system. </p>
<p>Specialised treatment plants process this wastewater. A combination of technologies is used to achieve the treatment objectives, based on the character of raw wastewater and use of the treated wastewater. These processes include primary, secondary and tertiary treatment. </p>
<p>Wastewater treatment seeks to remove:</p>
<ul>
<li><p>organics (proteins, hydrocarbons, oils and fats)</p></li>
<li><p>suspended solids (small particles)</p></li>
<li><p>bacteria (such as <em>E. coli</em>).</p></li>
</ul>
<p>In Victoria, as elsewhere in Australia, wastewater must meet strict standards. Water corporations achieve this by implementing stringent procedures and processes, and monitoring water quality. </p>
<p>But even after treatment, some contaminants can remain. These can be divided into “emerging” and “legacy” contaminants.</p>
<p><a href="https://www.epa.gov/wqc/contaminants-emerging-concern-including-pharmaceuticals-and-personal-care-products">Emerging contaminants</a> include pharmaceuticals, pesticides, phthalates (used to make plastic more durable), industrial chemicals and chemicals in personal care products. </p>
<p>They’re described as “emerging” because of the limited information we have about them, the risks they pose and the dose-response effects, especially at low, ultra-trace concentrations.</p>
<p>Legacy contaminants include, for example, PFAS, trace metals and insecticides such as DDT. </p>
<p>So should we be concerned about contaminants in treated wastewater? Our <a href="https://www.epa.vic.gov.au/about-epa/publications/2054---recycled-water-emerging-contaminants-report#:%7E:text=Emerging%20contaminants%20include%20pharmaceuticals%2C%20pesticides,environment%20and%2For%20human%20health">new research</a> examined this question.</p>
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Read more:
<a href="https://theconversation.com/pfas-for-dinner-study-of-forever-chemicals-build-up-in-cattle-points-to-ways-to-reduce-risks-201553">PFAS for dinner? Study of 'forever chemicals' build-up in cattle points to ways to reduce risks</a>
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<h2>What did the study find?</h2>
<p>EPA scientists partnered with the Victorian Department of Energy, Environment and Climate Action and 13 <a href="https://www.water.vic.gov.au/water-industry-and-customers/victorian-water-corporations">state water corporations</a> to investigate emerging contaminants in wastewater. As a science-based regulator, EPA undertakes problem-based research on pollution and waste to protect the health of Victoria’s community and environment. It uses data and evidence from studies like these to guide future actions.</p>
<p>We collected 230 samples of treated and untreated water at a range of wastewater treatment plants. We analysed these for the presence of 414 emerging and legacy contaminants.</p>
<figure class="align-center ">
<img alt="Outflow from a wastewater treatment plant" src="https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/514566/original/file-20230309-26-5wmidx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">For the study, 230 samples of treated and untreated water were collected from wastewater treatment plants.</span>
<span class="attribution"><span class="source">Image: EPA</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We detected 180 contaminants in treated and untreated water. These included:</p>
<ul>
<li>48 chemicals found in pharmaceuticals and personal care products</li>
<li>5 endocrine-disrupting chemicals</li>
<li>21 per- and polyfluoroalkyl substances (PFAS)</li>
<li>34 herbicides</li>
<li>8 insecticides</li>
<li>7 fungicides</li>
<li>12 industrial compounds</li>
<li>7 phenols</li>
<li>28 disinfection byproducts.</li>
</ul>
<p>None of the contaminant levels in treated water exceeded human health guidelines for <a href="https://www.waterquality.gov.au/guidelines/drinking-water">drinking water</a> and water used for <a href="https://www.nhmrc.gov.au/about-us/publications/guidelines-managing-risks-recreational-water">recreation</a>. </p>
<p>As you might expect, concentrations of most emerging contaminants were lower in treated than untreated water. However, some contaminants remained in treated water. Examples included antidepressant venlafaxine and anticonvulsant medication carbamazepine. </p>
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Read more:
<a href="https://theconversation.com/a-fishy-problem-how-antidepressants-may-impact-the-health-of-our-aquatic-ecosystems-197514">A fishy problem: How antidepressants may impact the health of our aquatic ecosystems</a>
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<p>So which treatment method is best? Based on our study, it’s one that combines all of the following:</p>
<ul>
<li><p>an “activated sludge” process, which can be aerobic or anaerobic – if aerobic, air is needed and is introduced into the “mixed liquor” by aeration devices or by natural diffusion</p></li>
<li><p>extended aeration using a mechanical device to aerate the water</p></li>
<li><p>disinfection with ultraviolet light, which uses UV radiation to break down the DNA of pathogens</p></li>
<li><p>microfiltration, a membrane process that removes particles larger than 0.1 micron </p></li>
<li><p>reverse osmosis, which is another membrane process and removes most of the salt and large molecules, producing water with very low dissolved content</p></li>
<li><p>disinfection with chlorination, zonation or UV disinfection. </p></li>
</ul>
<p>But treatment that combines all the above processes is relatively rare. It’s used by only four out of 200 wastewater treatment plants in Victoria. These plants produce the highest grade of recycled water.</p>
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Read more:
<a href="https://theconversation.com/the-yuck-factor-pushes-a-premier-towards-desalination-yet-again-but-history-suggests-recycled-waters-time-has-come-188795">The 'yuck factor' pushes a premier towards desalination yet again, but history suggests recycled water's time has come</a>
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<h2>What does this mean for the environment?</h2>
<p>None of the contaminants we detected in treated wastewater breached human health guidelines. However, we should not forget the environment. </p>
<p>Pharmaceutical pollution, in particular, is a pressing global issue. A <a href="https://www.pnas.org/doi/10.1073/pnas.2113947119">recent study</a> detected pharmaceuticals in 258 rivers in 104 countries across all continents. Pharmaceutical chemicals break down quickly in the environment, but are continually being replenished.</p>
<p><a href="https://www.who.int/publications/i/item/9789241549950">According to</a> the World Health Organization, trace quantities of <a href="https://pubs.acs.org/doi/10.1021/acs.est.8b05592">pharmaceuticals in drinking water</a> are very unlikely to pose risks to human health. But <a href="https://royalsocietypublishing.org/doi/10.1098/rstb.2013.0569">information</a> about the <a href="https://pubmed.ncbi.nlm.nih.gov/29193285/">potential</a> <a href="https://www.tandfonline.com/doi/abs/10.1080/15287394.2017.1352214">environmental</a> <a href="https://pubmed.ncbi.nlm.nih.gov/28063712/">effects</a> remains limited.</p>
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Read more:
<a href="https://theconversation.com/80-of-household-water-goes-to-waste-we-need-to-get-it-back-125798">80% of household water goes to waste – we need to get it back</a>
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<h2>You can make a difference</h2>
<p>Environmental authorities regulate how businesses and industry use, store and dispose of their waste. However, your actions at home – no matter <a href="https://www.sustainability.vic.gov.au/recycling-and-reducing-waste/at-home/small-acts-big-impact">how small</a> – can mean fewer contaminants make it to wastewater treatment plants.</p>
<p>Actions you can take include:</p>
<ul>
<li><p>take medicines only as directed and return unwanted and expired medicines to a pharmacy </p></li>
<li><p>choose chemical-free cleaning products</p></li>
<li><p>minimise pesticide use in your garden and bug sprays in your home</p></li>
<li><p>if you have a wastewater management system at home, such as for greywater or blackwater, maintain it regularly and avoid using powerful chemicals. </p></li>
</ul>
<h2>Next steps</h2>
<p>Further research is under way involving the Victorian EPA, water corporations and research institutions. It aims to build our understanding of what, if and how emerging contaminants are present in soil and taken up by crops irrigated with recycled water. </p>
<p>Ultimately, the work will reduce the potential risks to people and the environment posed by wastewater, by ensuring official advice is current and evidence-based.</p>
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<p><em>The report’s authors are EPA Scientists Minna Saaristo, Simon Sharp, Shanli Zhang and Mark P. Taylor.</em></p><img src="https://counter.theconversation.com/content/199668/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Patrick Taylor is a full-time employee of EPA Victoria, appointed to the statutory role of Chief Environmental Scientist. He is also an Honorary Professor at Macquarie University. This research was supported by funding from the Department of Energy, Environment and Climate Action and Victorian water authorities to EPA Victoria.</span></em></p>We detected 180 contaminants in treated and untreated water. None of those found in treated water breached human health guidelines, but we should not forget about potential impacts on the environment.Mark Patrick Taylor, Victoria's Chief Environmental Scientist, EPA Victoria; Honorary Professor, School of Natural Sciences, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1931112022-10-28T00:44:46Z2022-10-28T00:44:46ZWhat’s in the mud? Flood victims’ fears eased by early test results<p>Flooding stirs up river sediments, which can <a href="https://doi.org/10.1016/j.jhazmat.2021.126691">spread contaminants</a> in our waterways and floodplains. Flood water can carry sediments bearing <a href="https://eos.org/articles/when-rivers-are-contaminated-floods-are-only-the-first-problem">contaminants from a range of sources</a>, both historical and new, such as sewage, petrol stations, industrial yards and farming areas. This is worrying many people whose homes and gardens have been hit by repeated floods across eastern Australia. </p>
<p>One of the sites of the latest flooding is the suburb of Maribyrnong in Melbourne’s inner west. The Maribyrnong River’s industrial past means <a href="https://www.epa.vic.gov.au/about-epa/publications/2037">swimming was already not recommended</a>. The community has longstanding concerns about water and sediment quality. The flood washed those concerns right into the <a href="https://www.theage.com.au/national/victoria/i-need-start-all-over-again-the-clean-up-in-maribyrnong-begins-20221015-p5bq0h.html">homes of hundreds</a> of residents.</p>
<p>In response, EPA Victoria’s Science division mobilised last week, at the request of Maribyrnong Council, to provide some answers for residents. We took samples from the river at three locations. We also collected and analysed flood sediments in public areas and residents’ gardens. </p>
<p>The <a href="https://www.epa.vic.gov.au/for-community/flood-impacted-rivers">results so far</a> from across the impacted area are consistent – the chemicals and compounds analysed were mostly below levels of concern for human health. The exception was concentrations of pathogens like <em>E. coli</em>, which is linked to sewage. Exposure to sunlight is expected to reduce these pathogen levels. </p>
<p>The best thing you can do to protect yourself at these times is to stay clear of the river and wear gloves, boots and masks while cleaning up. Leave your dirty shoes outside and wash your hands regularly. While flood conditions and clean-ups continue, stay abreast of the <a href="https://www.epa.vic.gov.au/for-community/incidents/victorian-floods-october-2022">most recent advice</a> on managing the hazards.</p>
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<img alt="A man in a hi-viz vest kneels down to collect a sample from a nature strip" src="https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492045/original/file-20221027-29153-bp702g.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">An EPA worker collects samples from sediments left by the floods in Maribyrnong.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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Read more:
<a href="https://theconversation.com/dont-go-wading-in-flood-water-if-you-can-help-it-its-a-health-risk-for-humans-and-dogs-too-178027">Don't go wading in flood water if you can help it. It's a health risk for humans – and dogs too</a>
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<h2>Why was Maribyrnong at high risk?</h2>
<p>The river flooding raised significant concerns in the community because it drains from an industrial catchment with <a href="https://www.epa.vic.gov.au/for-community/current-projects-issues/pfas-in-maribyrnong-catchment">known contamination</a>. The catchment is also home to <a href="https://www.melbourneairport.com.au/Corporate/About-us/Environment/PFAS-Management">Tullamarine Airport</a>, a known source of per- and poly-fluoroalkyl substances (<a href="https://www.epa.vic.gov.au/for-community/environmental-information/pfas">PFAS</a>). These industrial chemicals are persistent – they’re known as “<a href="https://phys.org/news/2022-10-chemicals-persist-wastewater-treatment-crops.html">forever chemicals</a>” – and spread easily through the environment. </p>
<p>Maribyrnong sits on a river floodplain, which accommodates excess water and sediment during high flow. The redistribution of contaminated sediment across such areas during floods is <a href="http://dx.doi.org/10.1016/j.ancene.2014.02.004">well established</a>. Research also has found examples of <a href="https://doi.org/10.1016/j.scitotenv.2013.12.079">toxicity in farm animals</a> from such events.</p>
<p>In addition to daily water sampling along the Maribyrnong, we have to date sampled sediment from 109 gardens and 13 public areas. To reflect the potential sources of contamination, flood water and sediment are being analysed for a suite of:</p>
<ul>
<li><p>potentially toxic trace metals – arsenic, cadmium, chromium, copper, manganese, nickel, lead and zinc</p></li>
<li><p>chemicals present in oil, coal and petroleum known as polycyclic aromatic hydrocarbons</p></li>
<li><p>PFAS</p></li>
<li><p>pathogen indicator bacteria including <em>E. coli</em> and <em>Enterococci</em>. </p></li>
</ul>
<figure class="align-center ">
<img alt="EPA worker stands next to his vehicle as he labels newly collected samples" src="https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/492049/original/file-20221027-18797-cqxe8o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The EPA tested for a wide range of contaminants in samples from 109 gardens and 13 public areas that were flooded in Maribyrnong.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
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Read more:
<a href="https://theconversation.com/victorias-wild-storms-show-how-easily-disasters-can-threaten-our-water-supply-162846">Victoria's wild storms show how easily disasters can threaten our water supply</a>
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<h2>So why are contamination levels not higher?</h2>
<p>Sediment cores from floodplains and riverbanks allow scientists to <a href="https://doi.org/10.1071/MF14111">evaluate what it contains</a>. Bands of coarse particles – sands and silts – from high-flow events are interspersed with finer clay deposited as the water recedes. Finer deposits often <a href="https://doi.org/10.1016/j.envpol.2007.05.011">contain more contaminants</a> than the coarser material. </p>
<p>This is because the surface-area-to-volume ratio of a particle increases with decreasing particle size. This means there is more surface area for <a href="https://publications.csiro.au/rpr/download?pid=csiro:EP149391&dsid=DS3">metal ions</a> and <a href="https://doi.org/10.1080/10934529.2019.1632625">organic contaminants</a> to bind to finer sediments.</p>
<p>Floods are known to <a href="https://doi.org/10.1016/j.geomorph.2013.10.004">deposit potentially toxic trace metals</a> on floodplains. However, other large flood events, such as the one caused by Hurricane Katrina in New Orleans in 2005, have <a href="https://www.newscientist.com/article/dn18934-hurricanes-cleaned-up-lead-laden-new-orleans/">produced outcomes</a> like we see in Maribyrnong, where clean sediments have been draped over more contaminated urban soils. </p>
<p>For example, <a href="https://www.epa.vic.gov.au/for-community/flood-impacted-rivers">results so far</a> show flood sediments contained average concentrations of lead, a well-known contaminant, about o<a href="https://www.legislation.gov.au/Details/F2013C00288/Html/Volume_2#_Toc351712081">ne-third of the national guideline</a> for residential gardens. Lead was an element of concern because of the <a href="https://wwiiathome.com.au/efm.html">former munitions factory</a> in Maribyrnong.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/backyard-hens-eggs-contain-40-times-more-lead-on-average-than-shop-eggs-research-finds-187442">Backyard hens' eggs contain 40 times more lead on average than shop eggs, research finds</a>
</strong>
</em>
</p>
<hr>
<p>Levels of PFAS chemicals were also very low. On average, concentrations were roughly a tenth of the <a href="https://haveyoursay.agriculture.gov.au/nemp-on-pfas/widgets/385062/documents">values regarded as being of concern</a> for human health. </p>
<p>Small amounts of perfluorooctane sulfonic acid (<a href="https://www.health.nsw.gov.au/environment/factsheets/Pages/pfos.aspx">PFOS</a>) and perfluorohexane sulfonic acid (<a href="https://www.industrialchemicals.gov.au/consumers-and-community/and-poly-fluorinated-substances-pfas">PFHxS</a>) were detected. This is unsurprising given the upstream sources at Tullamarine Airport.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1581434936384401408"}"></div></p>
<h2>What’s the next step?</h2>
<p>EPA Science has engaged the State Emergency Service to set up similar sampling in regional locations. This will help to provide the same evidence-based guidance to communities affected by floods in those areas. This work should begin next week, with the organisations working together on sampling and fast-tracked laboratory analysis. </p>
<p>The current focus of this new rapid response from EPA Victoria is for flood-impacted communities. The work will shortly shift to all Victorian residents who want to know what’s in their soil. Through EPA’s <a href="https://www.epa.vic.gov.au/for-community/get-involved/citizen-science-program/gardensafe">GardenSafe</a> program, they can have their garden soil tested, free of charge, for trace element contaminants and soil quality indicators.</p>
<p>Building homes on a floodplain, which by definition is a plain that floods and where homes will always be at risk, arguably <a href="https://www.csiro.au/en/research/natural-disasters/floods/causes-and-impacts">increases the impacts of climate change</a>. That said, it’s not a new venture for humans who have been taking advantage of accessible and organically rich floodplains <a href="https://climate-adapt.eea.europa.eu/en/metadata/publications/ranking-of-the-worlds-cities-to-coastal-flooding/11240357">for centuries</a>. </p>
<p>Given how much flood-prone land is now developed, the crux of long-term management is to <a href="https://theconversation.com/whats-causing-sydneys-monster-flood-crisis-and-3-ways-to-stop-it-from-happening-again-186285">ensure we are better prepared</a>. Future decisions should aim to create adequate space for rivers to <a href="https://theconversation.com/i-lived-through-hurricane-katrina-and-helped-design-the-rebuild-floods-will-always-come-but-we-can-build-better-to-prepare-153452">do their natural work</a>.</p>
<p>Rapid sampling and advice do not fix the root cause of the problem. However, this work can ease residents’ fears, allowing them to focus on cleaning up and rebuilding their lives after the flood.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/beyond-a-state-of-sandbagging-what-can-we-learn-from-all-the-floods-here-and-overseas-193011">Beyond a state of sandbagging: what can we learn from all the floods, here and overseas?</a>
</strong>
</em>
</p>
<hr>
<hr>
<p><em>The authors undertook the work discussed in this article as employees of the EPA Victoria.</em></p><img src="https://counter.theconversation.com/content/193111/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Patrick Taylor works for the Environment Protection Authority (EPA) Victoria. He is the Executive Director of EPA Science and is also Victoria's Chief Environmental Scientist. He is an Honorary Professor at Macquarie University, Sydney. The EPA funded the analysis of the samples mentioned in the article as part of its response to the Victorian statewide flood emergency. </span></em></p><p class="fine-print"><em><span>Kara Fry works for the Environment Protection Authority (EPA) Victoria. She is a Citizen Science Officer in EPA's Science Partnerships team. Previously, Kara was a research assistant at Macquarie University where she managed the citizen science programs VegeSafe and DustSafe. </span></em></p><p class="fine-print"><em><span>Paul Leahy works for the Environment Protection Authority (EPA) Victoria. He is the Principal Scientist - Freshwater. He is an Associate of RMIT University STEM College.</span></em></p>Foods stir up river sediments and can spread contaminants across the floodplain. It’s a risk in areas with a history of industrial pollution, like Maribyrnong, but EPA test results are reassuring.Mark Patrick Taylor, Victoria's Chief Environmental Scientist, EPA Victoria; Honorary Professor, School of Natural Sciences, Macquarie UniversityKara Fry, Honorary Researcher, School of Natural Sciences, Macquarie UniversityPaul Leahy, Research Associate, RMIT STEM College, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1574102021-03-29T02:20:05Z2021-03-29T02:20:05ZWe know hand dryers can circulate germs through the air. Why are they still used everywhere?<figure><img src="https://images.theconversation.com/files/392126/original/file-20210329-17-1jgdj3.jpg?ixlib=rb-1.1.0&rect=79%2C14%2C4713%2C3176&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Airborne contaminants, dirty toilet seats, mould and mildew: long before the coronavirus pandemic came around, the hygiene-focused among us knew public washrooms are grimy places.</p>
<p>Most adults visit the bathroom around <a href="https://www.sciencedirect.com/science/article/pii/S0002937802004246?via%3Dihub">8-10</a> times a day. With an average hand-drying time of 30 seconds, we can expect between 4-5 minutes of daily dryer use per person (and more for people with an <a href="https://www.nature.com/articles/s41598-020-60967-7">overactive</a> <a href="https://bmcurol.biomedcentral.com/articles/10.1186/s12894-020-00619-0">bladder</a> or similar disorders).</p>
<p>In an attempt to facilitate the hand washing process, are hand dryers adding to the filth by blowing contaminants around? And if so, why are they still common?</p>
<h2>The need to dry</h2>
<p>Drying hands is an essential part of the hand washing process. Wet hands can further the spread of microbes, since moisture facilitates their transfer from the skin to other <a href="https://www.cambridge.org/core/journals/epidemiology-and-infection/article/residual-moisture-determines-the-level-of-touchcontactassociated-bacterial-transfer-following-hand-washing/096E367EA0A0363A4BD750AE8A174DE2">surfaces</a>. </p>
<p>Compared to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2249283/">shaking your hands</a> dry after a wash, using an air dryer or paper towel greatly <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3538484/">reduces</a> the number of surface bacteria that <a href="https://pubmed.ncbi.nlm.nih.gov/12515399/">remain</a>.</p>
<p>Warm air dryers remove moisture from the hands through <a href="https://www.sciencedirect.com/science/article/abs/pii/S002561961200393X">evaporation</a>, while jet air dryers remove it by using <a href="https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2010.04838.x">sheer force</a> to disperse the droplets into the air.</p>
<figure class="align-center ">
<img alt="Bathroom wall with both paper towels and air dryer." src="https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/390324/original/file-20210318-23-1foj9am.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some bathrooms offer both paper towels and air dryers. Should you prioritise one of them?</span>
<span class="attribution"><span class="source">Christian Moro</span></span>
</figcaption>
</figure>
<p>It’s worth remembering hand dryers don’t <em>create</em> microbes and there’s usually only minimal bacteria on their <a href="https://aem.asm.org/content/84/8/e00044-18.abstract">nozzles</a>, too. In many cases air dryers can even be fitted with filters that help clean and remove contaminants from the air. </p>
<h2>Put a lid on it!</h2>
<p>Nonetheless, while dryers themselves aren’t necessarily unclean, their forced air can help circulate bacteria around the space. This is why the main focus should be on preventing bacteria from surfaces ever becoming aerosolised (entering the air) in the first place.</p>
<p>If a toilet’s lid is left open when it’s flushed, a fine aerosolised mist of microbes <a href="https://www.tandfonline.com/doi/full/10.1080/02786826.2013.814911">enters the air</a>. And this cloud of faecal matter can spread over an area of up to six square metres. </p>
<p>Research has shown even after flushing many times, a toilet can <a href="https://pubmed.ncbi.nlm.nih.gov/16033465/">continue</a> to emit contaminants into the air. In other words, a person infected with a virus could be spreading these germs for several hours after visiting the <a href="https://pubmed.ncbi.nlm.nih.gov/29651169/">bathroom</a>. </p>
<p>Public washrooms can therefore act as reservoirs for especially nasty bacteria, such as those which are resistant to <a href="https://aricjournal.biomedcentral.com/articles/10.1186/s13756-019-0500-z">antibiotics</a>.</p>
<p>So are paper towels the solution?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/coronavirus-and-handwashing-research-shows-proper-hand-drying-is-also-vital-132905">Coronavirus and handwashing: research shows proper hand drying is also vital</a>
</strong>
</em>
</p>
<hr>
<h2>Problems with paper</h2>
<p>Paper towels remove water by absorption and take contaminants with them when they’re binned. However, they can cause plumbing problems if flushed down the toilet, which require time and money to fix. </p>
<p>Additionally, paper towels need to be continuously purchased, restocked and disposed of as waste — all of which leads to increased costs. In a worst-case scenario towels may run out, prompting people to exit without drying their hands at all.</p>
<p>Granted, in a hospital setting a dryer’s forced air may move microbes onto items handled by health professionals and patients, such as phones or <a href="https://www.cambridge.org/core/journals/infection-control-and-hospital-epidemiology/article/from-the-hospital-toilet-to-the-ward-a-pilot-study-on-microbe-dispersal-to-multiple-hospital-surfaces-following-hand-drying-using-a-jet-air-dryer-versus-paper-towels/FA51D26C9C3DC261D35F122EF97593D5">stethoscopes</a>. So paper towels may be a more suitable option here.</p>
<p>But they still don’t provide an entirely sterile environment and can be <a href="https://www.journalofhospitalinfection.com/article/S0195-6701(18)30366-9/abstract">contaminated</a> by microbes circulating in the area.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Toilet paper stuck to shoe leaves bathroom" src="https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391342/original/file-20210324-19-cvnhyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If contaminated paper towels are discarded on the floor, people stepping on them can transfer germs via their shoes to outside areas.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Weighing the environmental impact</h2>
<p>Although hand dryers do produce carbon emissions, studies have <a href="https://www.abc.net.au/news/science/2018-11-07/paper-towels-warm-air-jet-hand-dryers-environment-hygiene/10468580">shown</a> warm air dryers (which rely on evaporation) generate up to <a href="https://dspace.mit.edu/handle/1721.1/103115">70% more emissions</a> than newer, fast jet dryers (which force out a rush of cold air). </p>
<p><a href="https://theconversation.com/the-great-bathroom-debate-paper-towel-or-hand-dryer-51197">Environmentally speaking</a>, warm air dryers and paper towels perform roughly the same, on average. </p>
<p>Using recycled paper towels doesn’t seem to help much, either. This is because they can’t be recycled further, due to chemicals added to increase their absorptive properties as well as the overall energy required to manufacture them.</p>
<p>In the US, around <a href="https://www.abc.net.au/news/science/2018-11-07/paper-towels-warm-air-jet-hand-dryers-environment-hygiene/10468580">six million tonnes</a> of paper towels end up in landfill each year.</p>
<h2>The dry debate continues</h2>
<p>Some <a href="https://theconversation.com/whats-the-most-hygienic-way-to-dry-your-hands-54196">research</a> has concluded paper towels make a more hygienic method for drying hands. Meanwhile, aggressive jet hand dryers seem to have shown the greatest potential for dispersing bacteria and particles <a href="https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/jam.13014">over wider distances</a>. </p>
<p>But there isn’t a clear winner in practise. A recent critical review <a href="https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/jam.14796">concluded</a> there wasn’t enough research weighing up both options and that until more robust studies were conducted, evidence-based public policy recommendations couldn’t be made. </p>
<p>This echoes both the <a href="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/myth-busters">World Health Organisation’s</a> and <a href="https://www.cdc.gov/handwashing/faqs.html">Centre for Disease Control’s</a> hesitance to offer recommendations for whether drying hands with air dryers is more or less effective than using paper towels.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-great-bathroom-debate-paper-towel-or-hand-dryer-51197">The great bathroom debate: paper towel or hand dryer?</a>
</strong>
</em>
</p>
<hr>
<h2>Tips for a healthy bathroom regimen</h2>
<p>While hand dryers can circulate contaminants around a space, the aim should be to stop germs from becoming aerolised in the first place. If the contaminants aren’t in the air to begin with, their dispersion from hand dryers is less of a worry.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="No standing on the toilet seat." src="https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391343/original/file-20210324-19-8hahnz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Common sense goes a long way in bathroom hygiene.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p><a href="https://link.springer.com/chapter/10.1007%2F978-3-030-47483-6_1">Health</a> <a href="https://link.springer.com/referenceworkentry/10.1007%2F978-981-13-6106-7_118-1">education</a> on this front is important. Simple recommendations include:</p>
<ul>
<li><p>closing the toilet lid before flushing</p></li>
<li><p>wearing a mask where recommended or required, especially for those who have respiratory tract symptoms or a cough</p></li>
<li><p>coughing or clearing your throat directly into a tissue and immediately throwing it in the bin</p></li>
<li><p>washing your hands regularly with soap and water and not forgetting to dry them, as wet hands are more likely to spread bugs and diseases. </p></li>
</ul>
<p>In areas where infection control and prevention are paramount, such as hospitals or food production areas, measures such as increased airflow and air filters can also help.</p>
<h2>The bottom line</h2>
<p>Using paper towels comes with recurring costs, logistical problems and environmental considerations. Meanwhile, air dryers can further circulate vapourised bacteria.</p>
<p>Managers of public washrooms have much to consider when deciding which method of hand drying to provide. In some scenarios, hand dryers do present as a better option, which is why we continue to see them in public washrooms.</p>
<p>Regardless of what option you choose, don’t forget drying is an essential part of the hand-washing process. Both air dryers and paper towels are, by a long way, better than using nothing at all. </p>
<p><div data-react-class="InstagramEmbed" data-react-props="{"url":"https://www.instagram.com/p/CMjdfhsjsCg","accessToken":"127105130696839|b4b75090c9688d81dfd245afe6052f20"}"></div></p><img src="https://counter.theconversation.com/content/157410/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>What side are you on, paper or dryer? In either case, here’s the bottom line on what to do after using the toilet.Christian Moro, Associate Professor of Science & Medicine, Bond UniversityCharlotte Phelps, PhD Student, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/954992018-04-24T10:53:48Z2018-04-24T10:53:48ZWhy are some ‘E. coli’ deadly while others live peacefully within our bodies?<figure><img src="https://images.theconversation.com/files/216041/original/file-20180424-94157-1hsgfxd.jpg?ixlib=rb-1.1.0&rect=98%2C71%2C2793%2C1859&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">From a human perspective, some strains are good, some are evil.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/e-coli-bacteria-close-72915928">fusebulb/Shutterstock.com</a></span></figcaption></figure><p><em>E. coli</em> outbreaks hospitalize people and cause food recalls pretty much annually in the United States. <a href="https://www.cdc.gov/ecoli/2018/o157h7-04-18/index.html">This year is no different</a>. </p>
<p>Obviously some <em>E. coli</em> can be deadly for people. But not all strains of these bacteria make you sick. In fact, you have a variety of strains of <em>E. coli</em> in your intestines right now – including one that’s <a href="https://doi.org/10.1016/0006-2952(72)90184-0">busy making the antioxidant vitamin K</a>, crucial for your and its survival.</p>
<p>Scientists <a href="https://scholar.google.com/citations?user=kyNhp3UAAAAJ&hl=en&oi=ao">like me</a> often characterize <em>E. coli</em> by the sugar coat they display on their cell surface. A molecule called a lipopolysaccharide is the anchor that displays a collection of sugars to their environment. </p>
<p>These sugars help the bacteria stick to surfaces and reveal their identity to your immune system. Human cells do this, too – your blood type is defined by sugars displayed on your blood cells, for instance.</p>
<p>The sugars <em>E. coli</em> display vary from strain to strain. Some sugar coats are associated with strains living symbiotically in your stomach – <em>E. coli</em> HS, UTI89 and CFT073 are some of the most commonly found to be helpful. Others are associated with illness – like <em>E. coli</em> O104:H4, also called enterohemorrhagic <em>E. coli</em> (EHEC), which caused a <a href="https://www.britannica.com/event/German-E-coli-outbreak-of-2011">major outbreak in Europe in 2011</a>. According to the CDC, this latest outbreak is due to <em>E. coli</em> O157:H7 – a strain that’s caused at least one food-borne outbreak in the U.S. each year since 2006.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=300&fit=crop&dpr=1 600w, https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=300&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=300&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=378&fit=crop&dpr=1 754w, https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=378&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/216039/original/file-20180424-94118-17qf7qx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=378&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A simplified diagram shows the lipopolysaccharide sugars on the exterior of a bacterium’s cell wall.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Gram_negative_cell_wall.svg">Jeff Dahl</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The letters and numbers that name a strain serve as a code for which sugars are present. While the sugars bacteria display aren’t what makes you sick, they’re quickly and easily detectable and help scientists and doctors differentiate whether a present strain will generate toxins that can make you ill.</p>
<p>Bacteria rely on what researchers term virulence factors: molecules that aid their survival while undermining your immune system. Both the EHEC and O157 strains of <em>E. coli</em> are able to make a virulence factor called a Shiga toxin. <a href="https://doi.org/10.1128/microbiolspec.EHEC-0024-2013">Shiga toxins were discovered</a> first in <em>Shigella dysenteriae</em>, the bacterium that causes dysentery. Later researchers discovered that the EHEC and O157 strains of <em>E. coli</em> <a href="https://doi.org/10.1016/j.cll.2009.11.001">had gained the gene for Shiga toxins</a> from the dysentery bacterium through a process called <a href="https://www.britannica.com/science/horizontal-gene-transfer">horizontal gene transfer</a>.</p>
<p>When bacteria reach a critical mass in your body after you eat a contaminated food, they secrete these toxins as part of their strategy for finding a new host. The toxins enter the cells of your intestines, causing symptoms including low-grade fever, stomach cramps, diarrhea (often bloody) and vomiting.</p>
<p>It’s virulence factors like these that are to blame for human illnesses and that give <em>E. coli</em> a bad name – even if all strains don’t deserve it.</p><img src="https://counter.theconversation.com/content/95499/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Erika A. Taylor receives funding from the National Institutes of Health (NIH). </span></em></p>E. coli bacteria are the frequent culprits behind outbreaks of food-borne illnesses. But not all strains are harmful; some are even helpful.Erika A. Taylor, Associate Professor of Chemistry and Environmental Studies, Wesleyan UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/847422017-09-29T02:35:41Z2017-09-29T02:35:41ZWorries about spreading Earth microbes shouldn’t slow search for life on Mars<figure><img src="https://images.theconversation.com/files/188019/original/file-20170928-2939-1iwisqx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Viking landers in the 1970s were the last to look directly for life on Mars.</span> <span class="attribution"><a class="source" href="https://images.nasa.gov/#/details-PIA00382.html">NASA/JPL</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>There may be no bigger question than whether we are alone in our solar system. As our spacecraft find new clues about the presence of liquid water now or in the past on Mars, the possibility of some kind of life there looks more likely. On Earth, water means life, and that’s why the exploration of Mars is guided by the idea of following the water.</p>
<p>But the search for life on Mars is paired with plenty of strong warnings about how we must sterilize our spacecraft to avoid contaminating our neighbor planet. How will we know what’s native Martian if we unintentionally seed the place with Earth organisms? A popular analogy points out that Europeans unknowingly brought smallpox to the New World, and they took home syphilis. Similarly, it is argued, our robotic explorations could contaminate Mars with terrestrial microorganisms.</p>
<p>As an astrobiologist who researches the environments of early Mars, I suggest these arguments are misleading. The current danger of contamination via unmanned robots is actually quite low. But contamination <a href="https://doi.org/10.1089/ast.2017.1703">will become unavoidable once astronauts get there</a>. <a href="https://www.nasa.gov/content/journey-to-mars-overview">NASA</a>, other agencies and the <a href="http://www.spacex.com/mars">private sector</a> hope to send <a href="https://www.nytimes.com/2017/09/28/science/elon-musk-mars.html">human missions to Mars by the 2030s</a>.</p>
<p>Space agencies have long prioritized preventing contamination over our hunt for life on Mars. Now is the time to reassess and update this strategy – before human beings get there and inevitably introduce Earth organisms despite our best efforts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188026/original/file-20170928-1449-h7tdl9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microbiologists frequently collect swab samples from the floor of clean rooms during spacecraft assembly.</span>
<span class="attribution"><a class="source" href="https://images.nasa.gov/#/details-PIA17368.html">NASA/JPL-Caltech</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What planetary protection protocols do</h2>
<p>Arguments calling for extra caution have permeated Mars exploration strategies and led to the creation of specific guiding policies, known as <a href="https://planetaryprotection.nasa.gov/">planetary protection</a> protocols. </p>
<p>Strict cleaning procedures are required on our spacecraft before they’re allowed to sample regions on Mars which could be a habitat for microorganisms, either native to Mars or brought there from Earth. These areas are labeled by the planetary protection offices as “<a href="https://www.nap.edu/catalog/21816/review-of-the-mepag-report-on-mars-special-regions">Special Regions</a>.”</p>
<p>The worry is that, otherwise, terrestrial invaders could jeopardize potential Mars life. They also could confound future researchers trying to distinguish between any indigenous Martian life forms and life that arrived as contamination from Earth via today’s spacecraft. </p>
<p>The sad consequence of these policies is that the multi-billion-dollar Mars spacecraft programs run by <a href="https://mars.nasa.gov/programmissions/overview/">space</a> <a href="http://exploration.esa.int/mars/44997-the-red-planet/">agencies</a> in the West have not proactively looked for life on the planet since the late 1970s.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188014/original/file-20170928-1438-4xut2s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dr. Carl Sagan poses with a model of the Viking lander in Death Valley, California.</span>
<span class="attribution"><a class="source" href="https://www.nasa.gov/sites/default/files/images/151106main_image_feature_599_ys_full.jpg">NASA</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>That’s when NASA’s Viking landers made the only attempt ever to find life on Mars (or on any planet outside Earth, for that matter). They carried out specific biological experiments looking for evidence of microbial life. Since then, that incipient biological exploration has shifted to less ambitious geological surveys that try to demonstrate only that Mars was “<a href="https://mars.nasa.gov/msl/mission/science/objectives/">habitable</a>” in the past, meaning it had conditions that could likely support life.</p>
<p>Even worse, if a dedicated life-seeking spacecraft ever does get to Mars, planetary protection policies will allow it to search for life everywhere on the Martian surface, except in the very places we suspect life may exist: the Special Regions. The concern is that exploration could contaminate them with terrestrial microorganisms.</p>
<h2>Can Earth life make it on Mars?</h2>
<p>Consider again the Europeans who first journeyed to the New World and back. Yes, smallpox and syphilis traveled with them, between human populations, living inside warm bodies in temperate latitudes. But that situation is irrelevant to Mars exploration. Any analogy addressing possible biological exchange between Earth and Mars must consider the absolute contrast in the planets’ environments.</p>
<p>A more accurate analogy would be bringing 12 Asian tropical parrots to the Venezuelan rainforest. In 10 years we may very likely have an invasion of Asian parrots in South America. But if we bring the same 12 Asian parrots to Antarctica, in 10 hours we’ll have 12 dead parrots.</p>
<p>We’d assume that any indigenous life on Mars should be much better adapted to Martian stresses than Earth life is, and therefore would outcompete any possible terrestrial newcomers. Microorganisms on Earth have evolved to thrive in challenging environments like salt crusts in the Atacama desert or hydrothermal vents on the deep ocean floor. In the same way, we can imagine any potential Martian biosphere would have experienced enormous evolutionary pressure during billions of years to become expert in inhabiting <a href="http://online.liebertpub.com/doi/abs/10.1089/ast.2015.1380">Mars’ today environments</a>. The microorganisms hitchhiking on our spacecraft wouldn’t stand much of a chance against super-specialized Martians in their own territory.</p>
<p>So if Earth life cannot survive and, most importantly, reproduce on Mars, concerns going forward about our spacecraft contaminating Mars with terrestrial organisms are unwarranted. This would be the parrots-in-Antarctica scenario.</p>
<p>On the other hand, perhaps Earth microorganisms can, in fact, survive and create active microbial ecosystems on present-day Mars – the parrots-in-South America scenario. We can then presume that terrestrial microorganisms are already there, carried by any one of the dozens of spacecraft sent from Earth in the last decades, or by the natural exchange of rocks pulled out from one planet by a meteoritic impact and transported to the other. </p>
<p>In this case, protection protocols are overly cautious since contamination is already a fact.</p>
<h2>Technological reasons the protocols don’t make sense</h2>
<p>Another argument to soften planetary protection protocols hinges on the fact that current sterilization methods don’t actually “sterilize” our spacecraft, a feat engineers still don’t know how to accomplish definitively.</p>
<p>The cleaning procedures we use on our robots rely on pretty much the same stresses prevailing on the Martian surface: oxidizing chemicals and radiation. They end up killing only those microorganisms with no chance of surviving on Mars anyway. So current cleaning protocols are essentially conducting an artificial selection experiment, with the result that we carry to Mars only the most hardy microorganisms. This should put into question the whole cleaning procedure.</p>
<p>Further, technology has advanced enough that distinguishing between Earthlings and Martians is no longer a problem. If Martian life is biochemically similar to Earth life, we could sequence genomes of any organisms located. If they don’t match anything we know is on Earth, we can surmise it’s native to Mars. Then we could add Mars’ creatures to the tree of DNA-based life we already know, probably somewhere on its lower branches. And if it is different, we would be able to identify such differences based on its building blocks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=473&fit=crop&dpr=1 600w, https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=473&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=473&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=594&fit=crop&dpr=1 754w, https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=594&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/188023/original/file-20170928-22252-1wes7l6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=594&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Bacterial species <em>Tersicoccus phoenicis</em> is found in only two places: clean rooms in Florida and South America where spacecraft are assembled for launch.</span>
<span class="attribution"><a class="source" href="https://images.nasa.gov/#/details-PIA17369.html">NASA/JPL-Caltech</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Mars explorers have yet another technique to help differentiate between Earth and Mars life. The microbes <a href="https://doi.org/10.1089/ast.2012.0906">we know persist in clean spacecraft assembly rooms</a> provide an excellent control with which to monitor potential contamination. Any microorganism found in a Martian sample identical or highly similar to those present in the clean rooms would very likely indicate contamination – not indigenous life on Mars.</p>
<h2>The window is closing</h2>
<p>On top of all these reasons, it’s pointless to split hairs about current planetary protection guidelines as applied to today’s unmanned robots since human explorers are on the horizon. <a href="https://doi.org/10.1016/j.actaastro.2009.08.015">People would inevitably bring microbial hitchhikers with them</a>, because we cannot sterilize humans. Contamination risks between robotic and manned missions are simply not comparable. </p>
<p>Whether the microbes that fly with humans will be able to last on Mars is a separate question – though their survival is probably assured if they stay within a spacesuit or a human habitat engineered to preserve life. But no matter what, they’ll definitely be introduced to the Martian environment. Continuing to delay the astrobiological exploration of Mars now because we don’t want to contaminate the planet with microorganisms hiding in our spacecrafts isn’t logical considering astronauts (and their microbial stowaways) may arrive within two or three decades.</p>
<p>Prior to landing humans on Mars or bringing samples back to Earth, it makes sense to determine whether there is indigenous Martian life. What might robots or astronauts encounter there – and import to Earth? More knowledge now will increase the safety of Earth’s biosphere. After all, we still don’t know if returning samples could endanger humanity and the terrestrial biosphere. Perhaps reverse contamination should be our big concern.</p>
<p>The main goal of Mars exploration should be to try to find life on Mars and address the question of whether it is a separate genesis or shares a common ancestor with life on Earth. In the end, if Mars is lifeless, maybe we are alone in the universe; but if there is or was life on Mars, then there’s a zoo out there.</p><img src="https://counter.theconversation.com/content/84742/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alberto G. Fairén receives funding from the European Research Council.</span></em></p>Planetary protection protocols try to make sure we don’t seed places like Mars with life from our planet. An astrobiologist argues they’re misguided – especially with human astronauts on the horizon.Alberto G. Fairén, Research Scientist at Centro de Astrobiología, Spain, and Visiting Scientist in Astronomy, Cornell UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/347952014-12-15T03:24:05Z2014-12-15T03:24:05ZHealth Check: how to avoid getting ill from chicken<figure><img src="https://images.theconversation.com/files/67073/original/image-20141212-6036-1o44imt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Avoiding undercooked chicken meat or liver will help prevent infection.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lexnger/11424241954">Alexa Clark/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Chicken meat is an extremely <a href="http://www.chicken.org.au/page.php?id=4#Consumption">popular and affordable</a> source of animal protein, and each Australian now consumes <a href="http://www.agriculture.gov.au/abares/publications/display?url=http://143.188.17.20/anrdl/DAFFService/display.php?fid=pb_agcstd9abcc0022013_11a.xml">approximately 43 kilograms of it every year</a>. But chicken is also uniquely prone to making people ill, due to contamination with bacteria.</p>
<p>Most people would know chicken meat can cause <em>Salmonella</em> infections, but there is a lesser known yet more common bacteria that also loves chicken meat and can make you ill. </p>
<p><em>Campylobacter</em> actually causes very similar clinical illness to <em>Salmonella</em>, but is less likely to cause outbreaks (defined as two or more people infected after eating a common food or meal) so gets less publicity than the outbreak-prone <em>Salmonella</em>. </p>
<h2>Making you ill</h2>
<p><em>Campylobacter</em> recently <a href="https://www.food.gov.uk/news-updates/campaigns/campylobacter/actnow">caused a stir in the United Kingdom</a>, after a survey found eight out of ten portions of poultry meat sold in supermarkets there were contaminated. The <a href="http://www.foodstandards.gov.au/publications/documents/Poultry%20survey%20rept%20March%202010.pdf">situation in Australia</a> is likely to be similar although limited recent data have been published. </p>
<p><a href="http://www.cdc.gov/nczved/divisions/dfbmd/diseases/campylobacter/"><em>Campylobacter</em></a> is, in fact, one of the leading causes of gastroenteritis from food around the world. Infection with this bacteria results in diarrhoea, abdominal cramping, and fever lasting up to a week. And while it’s rarely fatal, it can also result in chronic illnesses, such as reactive arthritis, irritable bowel syndrome, and Guillain–Barré syndrome.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=353&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=353&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=353&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=444&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=444&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67184/original/image-20141215-6027-1op4vem.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=444&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Campylobacter</em> is commonly found in the intestinal tracts of birds, but may not make them sick.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/26279436@N02/7010917319">Matt Davis/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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</figure>
<p>You can become ill from <em>Campylobacter</em> after eating contaminated foods, having close contact with infected animals or people, or by drinking contaminated water or unpasteurised milk. The link between contaminated chicken meat and <em>Campylobacter</em> infections in humans is not new, but it is possible to reduce the risk.</p>
<p>Consider the case of New Zealand. In the mid-2000s, that country had among the highest rates of <em>Campylobacter</em> infection in the world. <a href="http://www.eurosurveillance.org/images/dynamic/EE/V18N03/art20365.pdf">Studies examining the causes</a> of infection highlighted contaminated chicken meat as the main source. </p>
<p>In 2006, advocacy by New Zealand public health professionals <a href="http://wwwnc.cdc.gov/eid/article/17/6/10-1272_article">led to improved controls</a>, including interventions by the chicken meat industry and government, resulting in dramatic declines in infection. Since that time, New Zealand has <a href="http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20365">conducted surveillance of molecular strains</a> of <em>Campylobacter</em> to understand the sources of infections and monitor interventions in the food supply.</p>
<p>Australia has had consistently lower rates of <em>Campylobacter</em> infections than New Zealand, but higher incidence than countries <a href="http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=6418296&fileId=S0950268809990161">such as the United States</a>.
State-based health departments in Australia have actually reported a steady increase in cases in recent decades, although there has been a decline in the last couple of years as shown by the figure below. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=529&fit=crop&dpr=1 600w, https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=529&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=529&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=665&fit=crop&dpr=1 754w, https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=665&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/66838/original/image-20141210-6051-1lax597.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=665&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
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</figure>
<p>But these numbers don’t provide the whole picture. Many people who become infected don’t go to a doctor or get tested, meaning their illness is never reported. There are probably as <a href="http://wwwnc.cdc.gov/eid/article/20/11/13-1315_article">many as 179,000 cases</a> of foodborne <em>Campylobacter</em> infection in Australia annually.</p>
<p><a href="http://wwwnc.cdc.gov/eid/article/14/6/07-1008_article">A 2008 Australian study</a> on the sources of such infection in 2001-2, found 29% were likely to be due to chicken meat, 2% due to offal, 3% due to contact with puppies and 2% due to chickens less than six months old. But the majority of the infection sources were unable to be identified.</p>
<h2>Protecting against infection</h2>
<p><em>Campylobacter</em> is commonly found in the intestinal tracts of birds, but may not make them sick. Meat as well as the processing environment can become contaminated during the slaughter and processing of chickens, particularly <a href="http://www.fao.org/docrep/013/al742e/al742e00.pdf">when removing the feathers and intestines</a>.</p>
<p>Recent declines in <em>Campylobacter</em> infection in Australia are encouraging and have occurred despite increasing consumption of chicken meat. Nevertheless, consumers need to be on their game when it comes to handling and cooking meat from chickens and other types of poultry.</p>
<p>There are steps you can take to minimise your risk of infection. First, when storing chicken meat in the fridge, ensure it doesn’t touch food that will be eaten without cooking. It’s also important not to cut chicken meat up on a board that’s used for ready-to-eat foods, such as salads. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/67074/original/image-20141212-6060-17ge379.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Thoroughly wash all chopping boards and utensils used for raw chicken meat, as well as your hands.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/suanie/5594125057">suanie/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Even the juices from chicken meat and packaging can be contaminated with <em>Camplyobacter</em>. Avoid washing poultry prior to cooking to not contaminate your kitchen sink and benches. Make sure juices can’t drip on other foods in the fridge. And thoroughly wash all chopping boards and utensils used for raw chicken meat, as well as your hands; hot soapy water is vital. </p>
<p>Finally, cook poultry meat to an internal temperature of 75° Celsius (using a thermometer) and <a href="http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-cdi3504e.htm">don’t eat undercooked meat or liver</a>.</p>
<p>One reason we don’t see many foodborne <em>Campylobacter</em> outbreaks is because the bacteria doesn’t grow well on food, having a narrow growth range of between 37°to 42°C. The bacteria is, in fact, quite fragile, and can be killed by drying, exposure to oxygen-rich environments, and highs and lows in temperature, such as that achieved by cooking or freezing. </p>
<p>But lowering rates of contamination of chickens with <em>Campylobacter</em> requires government, industry, retailers, and consumers to work together, which is <a href="https://www.food.gov.uk/news-updates/campaigns/campylobacter/actnow">what the UK is doing</a> to resolve its poultry crisis. In 2012, the Australian government and industry developed <a href="http://www.foodstandards.gov.au/code/primaryproduction/poultry/pages/default.aspx">primary production and processing standards</a>. It may be some time before their effects can be assessed. </p>
<p>In the meantime, people cooking with raw chicken meat should be fastidious about food safety in the kitchen.</p><img src="https://counter.theconversation.com/content/34795/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Martyn Kirk receives funding from the Australian Research Council, the Commonwealth Department of Health, Food Standards Australia New Zealand, and NSW Food Authority.</span></em></p><p class="fine-print"><em><span>Cameron Moffatt receives funding from the National Health and Medical Research Council. Mr Moffatt works part time for the ACT Government Health Directorate. The views expressed in this article do not reflect those of his employer.</span></em></p>Chicken meat is an extremely popular and affordable source of animal protein, and each Australian now consumes approximately 43 kilograms of it every year. But chicken is also uniquely prone to making…Martyn Kirk, Convener, Master of Philosophy in Applied Epidemiology, Australian National UniversityCameron Moffatt, PhD candidate, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.