Job losses at troubled turkey firm Bernard Matthews will be seen as a "breach of trust", MPs warned as they raised concerns about its takeover.
The 1,800-strong workforce was told their positions would be "preserved" but months later 150 employees are facing redundancy.
MPs said they were "especially concerned" about food tycoon Ranjit Boparan's failure to pledge to deal with the hole in the employee pensions fund.
The Work and Pensions Committee has written to Mr Boparan calling for assurances about jobs and pensions following the takeover deal.
In a letter, chairman Frank Field said: "The committee is especially concerned as the purchase appears not to have including any undertaking to contribute towards repairing the deficit on the employee pension scheme."
Mr Field said administrators at the time of the sale said jobs were being preserved.
He added: "It is to be assumed that the job security assurances were made in good faith. However, the committee is now concerned to learn that some 150 employees are to be made redundant.
"This is bad news and may well be seen by employees as a breach of trust."
The committee has also written to GM's pensions trustees following the announcement that European operations are being sold the PSA Group.
MPs have asked what assurances have been given by the buyers or the Government over the Vauxhall pensions scheme, which has an £840 million deficit.