Two kosher food firms could be fined up to £70,000 after the UK Border Agency raided their factory.
Officers arrived at the premises of The Great Food Company and Gilbert Kosher Foods - in Bletchley.
Inside, Agency staff interrogated a total of 56 employees and spent two hours separating those who were legally entitled to work in the UK from those without correct permits.
Seven men were suspected of working illegally, five from The Great Food Company - three of whom were arrested at the scene, and two from Gilbert Kosher Foods.
