Arrests made at both meat plants raided on Tuesday
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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Fine tonight, clouding over through Monday with rain
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Cloudy with further outbreaks of rain
James Wright's weather forecast for Wales.