Immigration officers have arrested 35 suspected illegal workers.
The suspects, from Eastern Europe and Brazil, were picked up in two raids in Cambridgeshire and Lincolnshire.
The latest arrests took place on Monday morning in Wisbech, Cambridgeshire, after managers at a logistics company, which packages pet food, called in officials to check paperwork involving 13 workers.
On Friday, 22 land workers were arrested in a raid at a potato packaging plant in Spalding, Lincolnshire.
The company declined to comment.
All 35 are believed to have been living in Wisbech.