Campylobacter risk from chicken livers
The majority of raw chicken livers sold at retail in are infected with the campylobacter food poisoning bug, new research has revealed.
Researchers at the University of Aberdeen bought raw chicken livers from supermarkets and butchers over a two-year-period and tested them for bacteria. They found that 81% contained the campylobacter bug.
The study, which was published in the International Journal of Food Microbiology, also revealed that more than half (56%) of the strains of campylobacter found in contaminated chicken livers were on the list of the 10 most common strains that infect people.
Dr Norval Strachan, a researcher into food safety and epidemiology, at the University of Aberdeen, said: “There is a growing epidemic of human campylobacteriosis in the UK, with laboratory reports showing 69,281 cases in the UK in 2010, which is a 35% increase since 2005. These rates are likely to be substantial underestimates of the actual disease burden, because it is estimated that only one in seven cases are reported in the UK.
“The growing number of chicken liver campylobacter outbreaks may not explain the whole reason for high levels of human campylobacteriosis in the UK, since these outbreaks only encompass a small fraction of cases. However here we have shown that the prevalence of campylobacter in chicken livers is high and that a number of these strains are identical to those commonly found in humans.”
Strachan added that all caterers and home cooks should treat chicken livers as likely to be contaminated with Campylobacter, avoiding cross contamination and ensuring that the product is cooked adequately.
The study was funded by the Food Standards Agency (FSA). Dr Jacqui McElhiney, policy advisor at the FSA in Scotland, said: “Unfortunately, levels of campylobacter in raw chicken are high, so it’s really important that chefs thoroughly cook chicken livers fully to kill any bacteria, until there is no pinkness left in the centre, even if recipes call for them to be seared and left pink in the middle. It’s the only way of ensuring the pâté will be safe to serve to their customers.”
There are an estimated 500,000 cases of campylobacter infection in the UK each year, with more than 15,000 people hospitalised and approximately 75 deaths as a result. According to figures from the Health Protection Agency, 14 of the 18 campylobacter outbreaks last year were linked to chicken or duck liver pâté.
The study backs the findings of previous research, which has indicated a high incidence of campylobacter in chicken products. University of Aberdeen research conducted in 2006 found the bug in 90.4% of more than 100 shop-bought chickens. A New Zealand study showed that 90% of positive campylobacter chicken liver samples contained the bug in internal tissue and that flash-frying might be ineffective at killing all of the pathogen present.