Horse meat scandal sees testing demand rocket

Eurofins was one of two laboratories used by the Food Safety Authority Ireland (FSAI) to conduct testing on meat samples in December.  

Dr Bert Popping, director of molecular biology and immunology at Eurofins, said the demand on their testing services had increased dramatically and it had allocated extra resources to deal with the influx, including reallocating equipment from other lines of molecular testing.

“We are getting samples from all over Europe and it reflects the complexity of the meat chain.”​

PCR analysis​

Popping explained why polymerase chain reaction (PCR) was the optimum method for testing for the presence of horse DNA in meat.

“PCR is a highly specific method, it amplifies DNA to make copies and make a percentage and sequencing reliability is extremely high – it is used to catch burglars when they have left some DNA.”​

He said depending on factors such as the number of products received, the PCR analysis and sequencing could be done within a day with validated results in two days.

Reading Scientific Services Limited (RSSL) said real-time PCR, involves using primer sequences (short lengths of DNA) specific to horse, which can pair with any other horse DNA found in the sample.

The test then amplifies the specific DNA, like a biological photocopier, and these can be counted in real time as they are produced.

Popping stated that the laboratory had to date not come across any meat contaminated with donkey and said sequencing could be used to see what animal DNA was from.

When asked about how long the issue may last, he added: “It depends on the scale of the scandal, the products are not fresh so frozen ready meals could be in storage chambers and we could see a lengthy testing period.”​

He said stringent quality controls were needed to ensure this would not happen again, but added that food eaten now was the safest it had been for a long time due to the stringent controls applied.

Clarity is key​

Another issue is that samples tested using mitochondrial DNA, which is more highly conserved and abundant in animals than nuclear DNA, meant that the methods could not be used to quantify the amount of horse DNA found in beef.

RSSL said there was a danger that companies might make the wrong choices in testing and it was key to understand the limitations and what the results mean.

“Muscle cells contain many more mitochondriathan cells in other tissues, but there is no way of telling how many mitochondria might be in any given cell and they can vary from 1 per cell to 10,000.​

“As a simple illustration, the same amount of starting DNA could arise from a small amount of muscle meat containing many thousands of mitochondria, or from a large amount of other tissue containing many thousand fewer mitochondria.​

“In any given sample of…meat, there will be muscle meat, and potentially cells from other parts of the animal. Therefore there are no quick answers to testing, and no definitive way of saying how much horse DNA is in any given sample.” ​

Further developments​

Meanwhile, the UK Food Standards Agency (FSA) revealed today that eight of 206 horse carcasses tested for bute between 30 January and 7 February 2013 were positive and six were sent to France and may have entered the food chain.

The agency said it was gathering information and would work with the authorities to trace them.

Animals treated with bute are banned from entering the food chain as it may cause a serious blood disorder (aplastic anaemia) in humans in sufficient quantities.

It added that from this week, a positive release system had been in operation, meaning horse carcasses would have to test negative for bute before they can enter the food chain.

The UK Chief Medical Officer, Dame Sally Davies had earlier said "even if bute is found to be present at low levels, there is a very low risk indeed that it would cause any harm to health​”.

Tonio Borg, EU Commissioner for Health and Consumer Policy, said it was important to underline the evidence does not point to a health crisis, at yesterday’s meeting in Brussels.

“The issue before us today is therefore overwhelmingly one of fraudulent labelling rather than one of safety.​

“I hope that the national investigations will uncover soon the culprits.”​

A meeting of the Standing Committee of the Food Chain and Animal health (SCoFCAH) has been arranged for tomorrow (Friday) which is the same day of the FSA deadline for UK firms to submit test results for their beef products.