Gardai and the FSA are investigating how the meat made its way into the food chain
The men are aged between 35 and 55 and are being detained at Carrick on Shannon, Longford and Roscommon Garda Stations.
Gardai and officials from the Department of Agriculture and The Food Safety Authority are looking into a number of cases of fraud and deception involving tampering with horse passports and microchips.
Today's arrests come after a number of raids at farms, houses and meat factories in June of last year.
