RGDATA hired an independent consultancy to carry out a food safety and hygiene audit of two Aldi and two Lidl stores in Dublin.
It uncovered regulation breaches allegedly including dried blood on meat, discoloured gammon and bacon, fresh food kept at wrong temperatures, dirty freezers and dirty mops near food.
RGDATA director general Ailish Forde said: "Regardless of any cost or competitive pressures, there cannot be any compromising on food safety standards."
Aldi said it had not seen the report and could not comment, but its policy was to comply fully with regulations. Lidl declined to comment.