Every year, thousands of people in New Zealand fall sick with a serious stomach bug called Campylobacter – and many don’t know that the chicken meat industry is at the heart of the problem. This bacteria lurks in raw chicken, and it doesn’t necessarily just cause a bit of food poisoning. In some cases, it triggers life-altering complications like paralysis or long-term digestive issues.
What’s especially alarming is how this issue ties into the cruel, high-intensity farming of chickens raised for meat – birds bred to grow abnormally fast, living in cramped, dirty conditions that make them more vulnerable to stress and infection. These stressed-out chickens are perfect candidates for Campylobacter infection, and the consequences reach far beyond the farm.
But there is hope. A switch to higher-welfare farming systems, using slower-growing breeds and better living conditions, could reduce illness in both chickens and people. Fixing the chicken welfare crisis could also help stop a public health crisis.
What is Campylobacter?
Campylobacter is a dangerous bacteria behind most cases of food poisoning, both in New Zealand and around the world. Studies have shown it is the most common cause of bacterial gastroenteritis in people across the globe. Campylobacter symptoms often strike suddenly and can be severe: bloody diarrhoea, intense stomach cramps, vomiting, headaches, fever, and exhaustion. Signs of disease usually develop 2 – 5 days after being exposed to the Campylobacter bacteria, and in uncomplicated cases, symptoms take 1 – 2 weeks to resolve. People with weaker immune systems, such as children, the elderly, and people with immune system diseases, are more likely to be infected, though everyone is susceptible.
Is Campylobacter a serious illness?
Many people recover on their own, but the consequences can be devastating for others. Most cases of Campylobacter infection in healthy individuals do not require specific treatment, and resolve with rest and fluids. However, severe infections may require hospitalisation for more intensive treatment. Campylobacter can even lead to Guillain-Barré syndrome (GBS): a terrifying condition that can cause paralysis by triggering an autoimmune reaction, turning the immune system against the body’s own nerves. This can result in weakness, difficulty moving the body or coordinating body movements, pain, and in the most devastating cases, paralysis. Concerningly, New Zealand has the highest incidence of GBS in the developed world, with a worse prognosis in those of Māori descent. Irritable bowel syndrome and reactive arthritis are also possible complications.
Like all diseases, prevention is better than cure; given most cases of Campylobacter infection are foodborne, it is important to take precautions and actions to reduce the risk of exposure.
How do you get Campylobacter infection? What foods most commonly cause Campylobacter?
The majority of Campylobacter infections worldwide are caused by exposure to contaminated chicken meat. It’s not just eating raw or undercooked chicken meat – it’s the invisible bacteria left on hands, knives, and kitchen benches after handling it. While eating undercooked or raw chicken meat is a very high risk factor, bacterial exposure is thought to more often be related to poor hygiene, such as not washing hands or appropriately cleaning benchtops and kitchen utensils after preparing raw chicken meat.
It is estimated that 77% of Campylobacter infections in New Zealand originate from a chicken source. Other sources of infection include other contaminated meat or milk, infection from animals carrying the bacteria, and contaminated water sources. A large waterborne outbreak of Campylobacter happened in Havelock North in 2016, causing over 7,500 human infections.
A recent report by the Public Health Communication Centre Aotearoa found that Campylobacter infections in New Zealand, predominantly from chicken sources, have increased by 70% in the past 17 years, based on hospital admissions data. They also found that this came at a cost of almost $1.4 billion, involving management of over 600,000 cases of infection, 9,000 hospital admissions, and 60 deaths. As not all cases of Campylobacter will be specifically diagnosed and confirmed at the laboratory level, these figures are still likely to be an underestimate of the disease impacts.
Is Salmonella the same as Campylobacter? Is Campylobacter the same as E. coli?
Campylobacter is a different type of bacteria to both Salmonella and E. coli, though all these bacteria cause very similar signs of food poisoning, characterised by severe gastrointestinal signs such as diarrhoea. Salmonella in chicken meat has been detected in New Zealand, though is a less common issue than Campylobacter.
Why is Campylobacter frequently caused by raw chicken meat?
Campylobacter infection caused by chicken meat invariably starts with infection within the living chickens themselves. Chickens are a natural host for the Campylobacter bacteria, and it lives within their digestive systems. While it has previously been thought that it exists as a commensal organism, which would mean it lives within the host without causing any harm, more recent studies have shown that Campylobacter infection can cause disease in the birds themselves, too. Chickens are thought to originally be exposed to the bacteria via their environment, such as via rodents or workers and equipment that have been contaminated outside the chicken shed.
While the digestive tract is routinely removed when chicken bodies are prepared for sale, there is still likely to be contamination of the final meat product in this process. A European Union study found that chickens that carried a Campylobacter infection prior to slaughter were approximately 30 times more likely to have a contaminated body compared to birds that did not have an infection in life. Additionally, systemic infection, in which the Campylobacter spreads from the digestive tract into other organs of the host chicken, such as the liver, can occur, making human exposure more likely. Infection throughout the body is much more probable when chickens are stressed and experiencing poor welfare.
How to tell if chickens have Campylobacter?
As microscopic bacteria, there is no way for someone purchasing chicken meat to know if what they are buying is contaminated with Campylobacter. A perfectly normal-looking chicken breast could be carrying harmful bacteria. The poultry industry believes it will not be possible to produce a Campylobacter-free product in the near future.
Monitoring of Campylobacter contamination of chicken meat in New Zealand is predominantly via assessments at the end of primary processing at the slaughterhouse, and is tracked via the National Microbiological Database. The introduction of this level of monitoring resulted in a substantial reduction in New Zealand Campylobacter infections in 2007. However, despite dropping contamination rates detected in the processing chain, the human Campylobacter infection rate has still been increasing. Testing of chicken meat at the point of sale has shown contamination to be a consistent issue, showing a potential point of weakness between primary processing and sale of the final meat product.
The National Microbiological Database requires poultry processing facilities to meet a ‘Campylobacter Performance Target’, which defines the number of chicken bodies which may have a higher detectable number of Campylobacter in a given period. Again, it is acknowledged that fresh chicken meat will always have a degree of Campylobacter contamination.
Is Campylobacter killed by cooking?
Yes, Campylobacter is killed by thoroughly cooking chicken meat (or other meat products) prior to consumption. However, as previously advised, consumption of chicken meat itself is a rare cause of campylobacteriosis. Infection is much more likely if hands, kitchen surfaces and utensils have not been appropriately cleaned following preparation of chicken meat. Cross-contamination in the kitchen is the real danger.
In a further attempt to tackle the Campylobacter epidemic in New Zealand, the Public Health Communication Centre Aotearoa has suggested chicken meat which is assessed as having a higher risk is further processed prior to reaching the point of sale, such as being used in a pre-cooked or frozen product rather than marketed raw. Additionally, it recommends clear labelling advising of the dangers of fresh chicken meat products, to try to educate people about the risks associated with chicken meat preparation.
How can Campylobacter levels in chicken meat be reduced?
The real solution? Stop the infection before it starts – by improving how chickens are raised. Chickens bred for meat in New Zealand endure crowded, filthy sheds, and experience unnatural, rapid growth at the cost of their health, and ours.
Given the very strong link between Campylobacter infection in life and contamination of the final meat product, trying to reduce infection risk in chickens reared for meat is the most sensible way of reducing the ultimate risk to people. While appropriate processing and chemical treatments of meat, including washing chicken bodies with chlorine, will be used to try and reduce the risk of human infection, tackling the issue at the chicken farm will have clear benefits both to human infection risk and to animal welfare. A study has shown a linear relationship between how widespread Campylobacter is in a shed of chickens and the relative risk of human infection, i.e. if chicken flock prevalence decreases by 20%, human cases should likewise decrease by 20%.
Campylobacter infection has been found to have a very strong link to the levels of circulating stress hormones in chickens. As such, providing chickens that produce meat a life with good welfare and minimal stress will make them more resilient to infection by environmental bacteria. Sadly, chickens farmed for meat in New Zealand are not afforded a stress-free existence. A stressed bird is often a sick bird, and sick birds pass that risk onto people.
Why are chickens on New Zealand farms so stressed?
The life of a chicken farmed for meat in New Zealand is short, brutal, and full of suffering. The challenge starts before life even begins. Chickens are ‘doomed for failure’ due to their genetics. All chickens commercially farmed for meat in New Zealand belong to one of the unnaturally fast-growing breeds, the Ross 308 and the Cobb 500.
Fast-growing chickens satisfy the market demand for chicken meat at the expense of a life worth living for the birds themselves. Intense genetic selection has resulted in birds that reach their target weight for slaughter in only 34 – 39 days. Chickens bred for meat are only babies when their lives are ended to produce inexpensive chicken meat products. Genetic pressures and selective breeding have resulted in a 400% increase in chicken size in the meat industry from 1957 to 2005. Understandably, the body of a juvenile animal is not adapted to sustain such rapid growth. Chickens bred for meat suffer horrendous welfare issues as a result of their extreme growth rate. As the desirable breast muscle, which has been selectively bred to be very large in New Zealand breeds, outstrips the growth of the rest of the body, the birds become unable to support it.
Severe and painful developmental and inflammatory leg conditions result in chronic pain, lameness, and may cause an inability to walk. The weight of the birds, exacerbated by not wanting to move around due to leg pain, high stocking density, and soiled litter on the shed floor, results in painful pressure sores: hock burns and pododermatitis. As the circulatory system struggles to support an ever-increasing muscle mass, heart and circulatory failure are common consequences, causing the uncomfortable, terminal condition called ascites. Sudden death, thought to be due to heart attacks, is also commonplace.
When a body doesn’t work like it should, any other provisions for welfare, such as an enriched environment, become meaningless, as the birds are unable to make use of them. This combination of physiological stress and disease caused by body type, and an inability to ‘behave like a chicken’, result in a chronically stressed state.
A controlled study comparing fast-growing and slower-growing chicken breeds in the same environmental conditions assessed the inflammatory response caused by exposure to Campylobacter in each group of birds. Faster-growing groups consistently had a higher number of affected birds, and increased severity of inflammation. Only faster-growing birds went on to develop the clinical sign of diarrhoea.
These welfare issues can also exhibit a snowball effect; fast-growing birds in a chronic state of stress are more likely to be clinically affected by Campylobacter and develop diarrhoea. This diarrhoea will then increase the soiling of their litter, predisposing them to developing painful hock, skin and foot lesions.
Genetics must be addressed to improve the welfare of chickens bred for meat in New Zealand, and in turn, improve their immune systems and reduce their risk of infection by Campylobacter.
Poor environmental conditions exacerbate the anatomical issues that chickens bred for meat experience. A high stocking density, to attempt to produce as much chicken meat in as short a time as possible, is inherently stressful, as birds cannot spread out or attempt to exhibit normal behaviours.
In New Zealand, the Meat Chickens Code of Welfare (the Code) allows a stocking density of up to 38kg/m2; this is the equivalent of approximately 19 birds per square meter when grown. Even chickens provided with free range are often too cramped and suffering with pain to utilise this; the same applies to using any enrichment items such as straw bales to scratch and perch on or dustbaths to bathe in. Birds may also be subjected to artificial light for 20 hours per day to encourage additional food intake and growth, allowing them minimal time to sufficiently rest their bodies.
Two noteworthy stressors related to Campylobacter are transportation and thinning. The final days of the life of a chicken bred for meat involve long hours without food, painful handling, and overcrowded transport: all perfect conditions for bacteria to spread and thrive.
Transportation to slaughter is a very stressful process for chickens. Other than initial placement in the shed, this is the only direct human contact and handling most chickens bred for meat will have before the end of their lives. The Code allows birds to be fasted for up to 12 hours before transit. Food withdrawal has also been associated with an increased prevalence of Campylobacter in the chicken gastrointestinal tract.
At the time of catching, handlers can carry up to eight birds at any one time. Transport crates are incredibly crowded: a density of up to 65kg/m2 is allowable, with crates only a minimum of 22cm high. Upon reaching the slaughter facility, chickens will be held for a period of time, prior to the horrific slaughter process. Chickens will be defecating on one another and contaminating the environment further for all this time.
A study has found that transport significantly increases the excretion rate of Campylobacter by chickens, consistent with this markedly stressful experience. The paper advises that this risk of “extensive carcass contamination” needs to be considered and addressed.
Similarly, thinning is the process of removing a portion of birds for slaughter at an earlier age, while allowing the remaining birds to continue to grow for an additional length of time, to meet various market requirements and allow for a higher initial stocking density. This is an incredibly stressful event for birds both taken for slaughter, and for those left behind. This also runs a higher risk of bacterial infection and disease development in remaining birds, as they will be exposed to transport equipment and workers who have been in the external environment.
A recent study of Ross breed chickens on farms in Belgium found all equipment being used on each farm was contaminated by Campylobacter, and a third of flocks became infected by Campylobacter after the thinning process. A DNA analysis showed that in two thirds of chicken infection events, identical bacteria were found on transport crates, trucks and forklifts, indicating the origin of the infection. The combination of immense stress paired with a contaminated environment resulted in an anticipated high risk of Campylobacter in the birds.
The poor welfare experienced by chickens bred for meat on New Zealand farms results in a pronounced human health risk by making the birds much more susceptible to infection and disease from Campylobacter.
Image credit – RSPCA UK – RSPCA Assured
How can I help chicken welfare in New Zealand?
Ultimately, people power will drive the change to the current accepted standards of welfare of chickens bred for meat, resulting in a better life for millions of birds, and a substantial reduction in human public health risk.
The Better Chicken Commitment is a roadmap to healthier chickens and safer food. It sets out higher welfare standards to be adopted by businesses in New Zealand who wish to show a genuine commitment to a better life for chickens, while remaining commercially competitive. It follows an international framework, with major businesses signing on worldwide.
The Better Chicken Commitment outlines improved recommendations for stocking density, lighting, enrichment, litter, air quality, lack of cages, slaughter techniques and auditing requirements. Uniquely and critically, it also aims to reach the heart of the welfare problems of chickens bred for meat, by requiring a phase-out of fast-growing breeds to more moderately or slower-growing strains. Thinning is also not recommended, and where used, is limited to one thin per flock.
By improving the welfare of chickens farmed for meat in New Zealand, we can join the countries leading the way forward by showing our commitment to the health of both animals and people. With increased chicken health, the risk of human Campylobacter infections, and the associated strain on our health system, decrease substantially.
How can I get involved?
Businesses listen to their customers. The best way you can take action is to show businesses that you care about a brighter future for chickens in the food system. Animals Aotearoa is happy to help guide businesses to the adoption of their own Better Chicken Commitment strategy.
Consider contacting your favourite businesses to explain your commitment to chicken welfare, and the difference they can make by becoming a Better Chicken Commitment signatory. With more and more aligned businesses, chicken producers such as Ingham’s and Tegel will have no choice but to listen, and improve the lives of chickens nationwide.
TAKE ACTION NOW! Send a message to Nando’s to encourage them to commit to higher standards for chickens. It only takes a couple of minutes.