Chickens to be ‘superfrozen’ to kill food bug

The radical process is currently being considered to help curb the rampant levels of the food poisoning bacteria commonly found in uncooked poultry products.

Around two-thirds of fresh, raw chicken sold by retailers is believed to be contaminated with campylobacter, which can cause sever stomach upsets.

The FSA aims to reduce the proportion of birds in the highest category of contamination at UK poultry houses from 27 per cent to 10 per cent by 2015.

Dr Jacqui McElhiney, policy adviser on food-borne disease at the FSA in Scotland, said: “This process acts to temporarily cool only the very outer surface of the chicken carcass without freezing the meat itself. It involves exposing the surface of poultry carcasses to very low temperatures for a very short time, which reduces the numbers of campylobacter bacteria on the surface, as they are sensitive to an extreme cold shock treatment of this type.”

The infection, known as a zoonose, a bacteria transmitted from animals to humans by consuming contaminated foodstuffs, has risen steadily in Europe in recent years. While levels of salmonella have significantly declined over the last five years, campylobacter infections have risen. In 2010 alone, numbers rose by 6.7 per cent, with 212,064 cases across Europe and 266 deaths.

Although it performed well during trials, the “superfreezing” procedure has yet to be approved by the European Union and its legality is still to be determined, said McElhiney.

“The legal status of implementing this treatment will need to be assessed to establish whether chicken which has been treated in this way could still be marketed as ‘fresh’ chicken under the requirements of the Poultry Marketing Regulations. The FSA and Defra are working closely with the EU Commission to establish this,” she said.

Other interventions being trialled include the use of lactic acid to decontaminate the surface of raw chicken. The EU currently permits the use of drinking water only for processing raw chicken meat and has yet to approve any physical or chemical treatments which may reduce levels of campylobacter at the point of slaughter.

Professor Hugh Pennington, emeritus professor of bacteriology at Aberdeen University, said: “I think it’s about the only thing on the table to get rid of campylobacter contamination. The bacteria don’t like being messed around with the cold. Anything that shows any promise of eradicating campylobacter is a good thing to get the number of infections down.”

There were 6,312 cases of campylobacteriosis reported to Health Protection Scotland in 2012, compared with 4,365 cases in 2004. The greatest increase in the number of cases reported was in Shetland and Orkney.

The figures only account for those who have attended a GP and had a stool sample taken. However, it is understood that for every one confirmed case, as many as nine further cases occur but go unreported.

Nationally, there were 70,298 confirmed cases of campylobacteriosis reported in Britain in 2010, according to the most recent EU report carried out by the European Food Safety Association (EFSA).

The UK had the third largest number of confirmed cases among the 27 EU member states with 113.37 cases per 100,000 of the population, well above the EU average of 48.56.

Scotland’s total number of cases in 2012 soared to 120.9.

The bacteria, which multiply in the chicken’s intestines, enter the supply chain through the faeces of infected livestock or wild animals, contaminated water supplies or feed. In humans, they can cause inflammation with watery, sometimes bloody, diarrhoea as well as cramps and fever. Typically, symptoms can last from five to seven days.

Pennington said the prevailing assumption among consumers is that campylobacter infections are caused by cross-contaminating kitchen work surfaces, but said basic hygiene at home can help.

“Businesses don’t want people to think that their chickens have all got it, but for practical purposes the public should assume that the chicken they’re preparing is contaminated,” he said. “Handle it with care until it goes in the oven, wash your hands thoroughly and make sure the work surface is usable. Use plastic, colour-coded chopping boards that can be put in the dishwasher.”

He continued: “Don’t just wash your hands with hot water. Make sure you do it thoroughly. If it was done on a universal basis, there would be the expectation that there would be fewer cases of campylobacter infections. People see TV chefs cooking and some of them have bad practices, but that’s just a personal view.”

The EFSA maintains that a comprehensive assurance scheme would be the most efficient way to protect EU consumers, including monitoring producers’ food hygiene management and identifying the main hazards on the carcass.

Twitter: @David_M_Walsh