Six illegal workers were arrested at a business which has previously been prosecuted for similar offences.
Acting on a tip-off, immigration enforcement officers swooped on a factory used by UK Snacks Ltd in Orient Way, Leyton, at 11.30am on Wednesday.
Three people tried to avoid officers by hiding behind boxes while another tried to run away.
Five men were found to have overstayed their visas, while another was in breach of his visa conditions.
The business was warned it may be fined up to £10,000 per illegal worker arrested, unless it can prove that the correct checks were carried out.
Three people were also held during searches of properties in Walthamstow and Leyton on suspicion of breaking the terms of their visas.
All but one of those arrested is being detained pending removal from the UK.
The business was served a notice warning that it may be fined £10,000 per illegal worker arrested, unless it can prove that the correct checks were carried out.
A total of 12 illegal workers were arrested at the factory in October last year.
David Seymour-Smith, head of north London Home Office immigration enforcement team, said: “Illegal working is not victimless. It defrauds the taxpayer, undercuts honest employers and cheats legitimate jobseekers out of employment opportunities.
“The public can be a huge help and I urge people with information about suspected immigration abuse to get in touch.”