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.
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There will be long clear spells tonight, which will lead to a cold night for all.
Wales midfielder Joe Ledley has angrily denied accusations that he laughed at Seamus Coleman's horror injury in Dublin.
A dry, sunny and warm afternoon.