Checks on Halal meat in Derby have found items - described as lamb burgers and kebabs - which contained beef and chicken.
This means that the undeclared food might not have been prepared in the right way.
The recent operation also found lamb doner kebabs, made mostly of chicken and halal sweets, missing labelling which would help trace where ingredients came from.
Trading standards officers at Derby City Council took 20 samples of foods.
Two traders have been interviewed for offences under the Food Safety Act 1990 and received warnings, where they were told to change their practices or face charges.
Referrals were also made over the results for food from six other non-Derby based firms to trading standards teams in their areas.
A council spokeswoman said this was because of things like “minor labelling issues”
She said the names of the companies could not be revealed for legal reasons.
Followers of Islam are only permitted to eat Halal food which must have been slaughtered following a prayer to Allah.
It must be prepared in certain way – involving a cut to the jugular vein and the animals must be healthy at the time of slaughter.
A council spokeswoman said the problem with having undeclared meat mixed in with lamb is that there was no way of telling if it was Halal or not.
She said: “Following the horsemeat scandal, the trading standards team would have expected all traders to be compliant but some manufacturers haven’t replied to requests and others failed.”
Councillor Asaf Afzal, cabinet member for Streetpride and neighbourhoods, added: “Consumers rely on accurate food descriptions.
“Some foods are not permitted to be eaten by some religions and cultures and consumers should be able to have confidence that if they are buying an expensive product such as lamb, that they are not getting chicken instead, a meat that is half the price.
“When consumers visit their local takeaway, they may think they are eating local produce when in fact we have found Halal meat imported from Australia, Holland, New Zealand, Ireland, Thailand and Turkey.”
Some consider the process of preparing Halal meat controversial as it can involve slaughtering animals which have not been stunned to prevent them from experiencing pain or suffering.