Horse DNA has been found in a batch of canned sliced beef that has been sold in the UK, the Food Standards Agency has said.
The canned beef was manufactured in Romania in January 2013 and supplied to Home Bargains (TJ Morris Ltd) and Quality Save stores in the UK.
The affected products have been withdrawn from sale.
A split in responsibilities between the Food Standards Agency (FSA) and Whitehall in 2010 has led to confusion about the role of the FSA and Defra in responding to food authenticity incidents during the horsemeat scandal, according to a report.
An FSA review has already found that some of its staff and local authorities were confused about why the agency was taking the lead in investigating the incident during the early stages of the horsemeat incident.
The NAO said local authorities had reported that they remained unclear about who to contact regarding certain areas of food policy.
The Government must remove the confusion that marred the response to the horsemeat contamination crisis and improve its understanding of potential food fraud, according to a report.
The National Audit Office (NAO) said the Government failed to identify the possibility of adulteration of beef products with horsemeat, despite indications of heightened risk.
And it found that while arrangements for identifying and testing for risks to food safety were "relatively mature and effective", similar arrangements for the authenticity of food were not.
City of London Police were asked to work with the Food Standards Agency (FSA) as part of its inquiry into the scandal. It reviewed evidence from law enforcement agencies in Europe and the UK, as well as from the FSA.
The force launched an investigation in May and said it made the arrests "during the initial stages" of the inquiry. Officers also carried out searches at businesses and homes in the UK.
Detective Chief Superintendent Oliver Shaw, from the City of London Police, said:
This is an extremely complex investigation covering a number of jurisdictions and a variety of businesses.
We are working closely with police forces, other law enforcement agencies and regulators to determine whether horsemeat being used in a range of meat products was deliberate and coordinated criminal activity.
Two men have been arrested on suspicion of conspiracy to defraud by detectives investigating the horsemeat scandal, City of London Police said today.
- The MPs acknowledged that horsemeat contamination was limited to a "relatively small" number of beef products sold in the UK, with 99% of products tested containing no horse DNA
- Across the EU as a whole, 4.66% of products tested were found to contain more than 1% horse DNA
- The committee complained that there was still a "lack of clarity" within Whitehall over where responsibility lay for dealing with such issues
- It expressed "surprise" that in EU-mandated tests, 14 out of 836 samples of horsemeat from the UK tested positive for the painkiller bute - the highest number of positive tests in the EU
A statement from the House of Commons Environment, Food and Rural Affairs Committee said:
The evidence we received from retailers and food processors in the UK and Ireland suggests a complex, highly organised network of companies trading in and mislabelling frozen and processed meat or meat products in a way that fails to meet specifications and that is fraudulent and illegal.
We are concerned at the failure of authorities in both the UK and Ireland to acknowledge the extent of this and to bring prosecutions.
We are dismayed at the slow pace of investigations and would like assurance that prosecutions will be mounted where there is evidence of fraud or other illegal activity.
MPs have condemned the slow pace of the investigation into the horsemeat scandal, with no prosecutions six months after the problem was first identified.
The Commons Environment, Food and Rural Affairs Committee said the authorities in both the UK and Ireland - where horse DNA was first discovered in processed beef products - had yet to acknowledge the scale of the illegal activity involved.
The committee called for assurances that the authorities will act if evidence is uncovered to support criminal prosecutions.
We have started the year on track, despite a continued difficult economic environment for consumers.
This is notwithstanding our planned work on general merchandise, which has held back sales in the UK, and a small but discernible impact on frozen and chilled convenience food sales due to the customer response to equine DNA being detected in four products.
The outcome of three months of checks for horse DNA and the anti-inflammatory drug bute in processed food are expected today.
The regime of the investigation was agreed by EU ministers in February, including 2,500 random tests on processed food for horse DNA and 4,000 for bute.
The move comes as the Government announced it was launching a wide-ranging review into the horse meat scandal to restore consumer confidence in the food they buy.
The results of the investigation are expected to be declared in Brussels, at 11am UK time.