Which? finds 1 in 5 chickens on test contaminated Food-poisoning bacteria found in supermarket chicken

13 April 2012

Raw chicken

One in five supermarket chickens tested by Which? were contaminated with campylobacter.

And 17% were contaminated with listeria – both of which can cause food poisoning. 

Of the 192 samples tested by Which? 1.5% also tested positive for salmonella.

Contaminated chicken 

Which? tested whole chickens and chicken portions from nine supermarkets in March 2012. Of the 192 samples:

  • one in five (18%) were contaminated with campylobacter
  • 17% were contaminated with listeria, with 4% containing levels of listeria classed as high by the Food Standards Agency (FSA)
  • 1.5% tested positive for salmonella.

The Which? study was a snapshot, testing chicken samples from all the major retailers – Aldi, Asda, The Co-operative, Lidl, Marks & Spencer, Morrisons, Sainsbury's, Tesco and Waitrose.

The chicken samples were bought on two days in different locations. Bacterial contamination was found in samples from every retailer tested.

Campylobacter contamination

Although not a directly comparable test, the Which? results indicate an improvement on 2009, when the FSA found that 65% of fresh chickens it tested were contaminated with campylobacter at the point of sale.

Which? executive director Richard Lloyd said: 'While the situation is improving, it is unacceptable that one in five chickens we tested were found to be contaminated with campylobacter. 

'We want to see the risk of contamination minimised at every stage of production, because for far too long consumers have been expected to clean up mistakes made earlier in the food chain.'

Food poisoning risk

There were 84,560 recorded cases of food poisoning in England and Wales in 2010. 

But the actual number is expected to be much higher, as many people who get sick don't seek medical help. Those who do aren't always screened. 

In fact, the FSA estimates that campylobacter – the most common cause of food-borne illness – was alone responsible for 371,000 cases of food poisoning in 2009. 

The bacteria campylobacter, listeria and salmonella are easily transferrable and, although they are killed by cooking, most illness occurs from incorrect handling and cross contamination. 

Protection from food poisoning 

How you can protect yourself from food poisoning:

  • Packaging Make sure chicken is properly wrapped and in leak-proof packaging so that meat and meat juices don't come into contact with any other foods or work surfaces, and wash your hands after handling.
  • Refrigeration Refrigerate raw chicken (at or below 5ºC). Bacteria multiply faster at room temperature. Listeria can also multiply at refrigeration temperatures, so it’s important to stick to the use-by date.
  • Washing Don’t wash raw chicken, as you could splash the bacteria onto the sink, worktops or nearby dishes, increasing cross contamination.
  • Storage Store raw meat in a sealed container at the bottom of your fridge. Keep it separate from ready-to-eat foods such as ham and salad. As these don’t need cooking, any bacteria transferred to them won’t be killed.
  • Preparation Use different chopping boards and knives for preparing raw meat and other foods, and wash your hands with soap and warm water after handling.
  • Cooking It’s vital to cook chicken thoroughly – the inside must be piping hot with no pink bits, and juices must run clear. Cooking at temperatures above 70ºC (165ºF) will kill bacteria.

Food safety 

In theory, manufacturers could reduce bacterial contamination by treating chickens, eg using chemicals - but our research shows that most consumers wouldn't be willing to buy chickens treated in this way. 

For instance, not everyone is keen on having their chicken treated chemically, and manufacturers don't want to introduce treatments that their customers aren't happy with.

A Which? survey of 1,406 UK adults showed that 82% of the public want controls in place throughout the food chain so that chickens aren't infected – rather than dealing with contamination at the end of the process.

But when asked about specific treatments, 59% said they were unlikely to buy chicken treated with safe levels of irradiation. 

60% were unlikely to buy chicken that had been sprayed or washed with a mild acid such as lactic acid, and 67% were unlikely to buy chicken that had been treated with chlorine. 

People were more accepting of stream treatment, with 59% saying they were likely to buy a steam treated chicken. 

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