The 10 beef burger products that tested positive for horse DNA were as follows:
Limit of Quantification, or LOQ, is the lowest quantity of a substance that can be distinguished from the absence of that substance.
- Tesco, Everyday Value Beef Burgers - 29.1%
- Aldi, Oakhurst Beef Burgers - 0.3%
- Dunnes Stores, St. Bernard Beef Burgers - LOQ
- Lidl, Moordale Beef Burgers - LOQ
- Tesco, Beef Quarter Pounders - 0.1%
- Lidl, Moordale Ultimate Beef Burgers - LOQ
- Lidl, Moordale Quarter Pounders - 0.1%
- Dunnes Stores, Flamehouse Chargrilled Quarter Pounders - 0.1%
- Iceland, Quarter Pounders Batch 2250 A 15:27 - 0.1%
- Iceland, Quarter Pounders Batch 2218 A 15:55 - 0.1%
The Food Standards Agency have said:
"The FSA has been made aware of the survey results in which equine DNA was identified in some beef burgers and is working with the Food Safety Authority in the Republic of Ireland to investigate the issue.
"However, at this stage it is not believed to be a food safety risk.
We are aware that investigations are ongoing to ascertain how or why horse meat was used in the products."
Supermarket chain Aldi have said they are conducting their own investigation after traces of horse DNA was found in their frozen beef burgers.
A spokesman said: "We have sought information from one supplier, Silvercrest, which is dealing directly with the FSAI on the issue that has been raised."
The Food Safety Authority has found traces of horse DNA in burgers made at plants in the UK - including Dalepak in Hambleton, North Yorkshire.
The meat also came from two processing plants in Ireland - Liffey Meats and Silvercrest Foods.
The burgers were on sale in Tesco, Dunnes Stores, Lidl, Aldi and Iceland.
A total of 27 products were analysed, with ten of them containing horse DNA, while 23 of them tested positive for pig DNA.
Horse meat accounted for approximately 29 per cent of the meat content in one sample from Tesco.
The FSA said the findings do not pose a risk to public health.
However, it said that it raises concerns about the traceability of meat ingredients.