Factory-farmed chickens: breeding ground for a health hazard. Photograph: Patty Mark/AFP/GETTYIMAGES
Once out of reach of most people's pockets, chicken is now an affordable part of the UK diet. Our appetite for factory chicken has gone up as fast as its price has come down. As a lean, nutritional meat, it comes with marked health benefits. But, of late, it appears that much cheap, factory-farmed chicken comes with something else: the food poisoning bacteria,campylobacter.
In industry, as well as in government and supermarket circles, campylobacter has been talked about for a decade or more. But that conversation, it seems, has only recently become newsworthy.
Present in around two-thirds of chicken in shops, campylobacter is the main cause of food poisoning in the UK, responsible, it is estimated, for more than 22,000 hospitalisations every year, around 100 deaths, as well as potential long-term health problems.
Campylobacter grows well in chickens, but it has proved surprisingly hard to isolate and the industry has become increasingly frustrated by the difficulty of pinpointing an outbreak.
Perhaps for that reason, public attention has largely focused on meat contamination down the line, in slaughterhouses and food-processing plants. That is all well and good. But such largely predictable failings draw attention away from what is arguably a more important problem with factory chicken: churning out a highly perishable product on an industrial scale provides the prime conditions for the amplification and spread of campylobacter.
It's the very way we produce chickens prior to slaughter, especially the "just in time" governing principle, that is the issue, not the all too predictable incidents of carcass contamination.
In a tightly controlled production system, everything from breeding and hatching, to growing, to slaughter and the processing of the birds, is planned to the last detail. There is little slack in the system. Day-old chicks have to be delivered to contract farmers in the right numbers. Birds have to bulk up to market weight at the right time to meet low supermarket prices.
The right number at the right size have to balloon through the system for chicken to be affordable.
All of this is calculated backwards, from the supermarket shelf to the hatcheries, so that farmers are under constant pressure to match the throughput of numbers and standardised weights on a just-in-time basis. What is not factored in is that an intensive, tightly coupled food operation may actually harbour disease and accelerate its mutation and spread.
House tens of thousands of virtually genetically identical birds indoors in densely crowded conditions, pump them full of enriched feeds and drugs that stimulate growth and weaken their immune systems and you have a perfect ecology for disease incubation. When thousands of chickens are packed in industrial sheds, their accelerated lives may leave them with compromised and stressed bodies, increasing their vulnerability to campylobacter.
The risk is embedded within the production system itself. Or, to borrow a classic phrase from the Yale sociologist Charles Perrow, accidents in such operations are "normal", inevitable given the way that different parts of the system interact. Put another way, campylobacter is an accident waiting to happen.
It doesn't take much to tip a flock of chickens, jam-packed and in stressful conditions, over a threshold, from healthy to diseased. Small changes can do it, especially, as the industry well knows, around the time when flocks are "thinned".
As chicks put on the required weight, the sheds become crammed and risk violating welfare regulations about stocking densities, as well as going beyond their supermarket price point. So around a quarter of the birds are taken out of the shed when they are around four to five weeks old. The rest are left to grow on to the next supermarket price point.
It makes commercial sense to "thin" flocks. In an industry that runs on very low profit margins, it maximises the profitability of shed space. But the stress of the "thin" also leaves the remaining birds vulnerable to opportunistic infection by campylobacter. Stretched by accelerated growth cycles and at a life stage when their immunity is low, the flocks can reach a tipping point where a combination of small changes can have a big effect. In fact, a flock of 30,000 chickens can turn positive for campylobacter almost overnight. It's that rapid.
Before the "thin", the chickens are deprived of sleep for 24 hours and their food and water removed so that their stomachs are empty before slaughter. A contract catching team is responsible for getting the birds from the sheds to the processing plant. Catching chickens is physically demanding work, performed in semi-darkness and "stupidly hot" conditions, as one catcher told us. Up to their ankles in chicken litter, the catchers collect handfuls of birds.
It takes around 45 minutes to an hour for a team of five catchers to complete a lorry load, with teams catching up to 5,500 birds an hour, 34,000 birds a shift, depending on the requirements of the processor. The catchers know these numbers well. They have to keep up with them, for these are the numbers that feed the high throughput at the processing plant, which, in turn, keeps the price of chicken low.
Food safety is a big issue and factory chicken is up there on the high-risk register. Oddly, though, until recently the main concern of the industry and the supermarkets has been protecting chickens from human contamination, not the reverse.
Contamination incidents, such as meat dropped on the floor or pumps breaking down, happen when tightly coupled production systems are run at breakneck speeds. Yet efforts can be made to prevent such routine failings. Hygiene can be improved and corners prevented from being cut. Back-up devices can be put in place. But the "normal" accident that is campylobacter is embedded in the industrial way we produce our food, as the direct result of its just-in-time pressures. It's the high price that we pay for low-cost chicken.
John Allen is Professor of Economic Geography at the Open University. Stephanie Lavau lectures at the School of Geography, Earth and Environmental Sciences, Plymouth University. Their work is funded by the Economic and Social Research Council.