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 was a serious reason behind a man dressed as a bug and an AM holding a giant inflatable mallet.
The Welsh TUC has today launched a campaign calling for 'better jobs, closer to home' for Valleys communities.
A wet and windy start to the week, with scattered showers becoming locally heavy at times.