A 63-year-old man was also arrested at Peter Boddy Slaughterhouse in West Yorkshire, the other plant where operations were suspended on Tuesday in an investigation by the Food Standards Agency.
Dyfed-Powys Police has confirmed three people are being held on suspicion of offences under the Fraud Act.
They are being detained at Aberystwyth Police Station, where they will be interviewed jointly by the police and the FSA.
More top news
The family of an elderly woman from Swansea have been trying to sell her house to pay for her care.
Welshman Nathan Cleverly will face Tony Bellew in Liverpool on the 22nd of November. It's three years since their last fight
It will become dry in the evening. Northern and central parts will become mostly clear and cold, with fog patches.