The mistake - which occurred on December 12, last year - has left Muslim parents fuming at the multi-faith secondary school forcing the headteacher into an apology.
All meat served to the 1,400 students at the school is Halal, regardless or race or religion.
On Monday parents received a letter from headteacher Carl Jansen, who apologised for the 'unintentional error'.
But despite the action, parents were still furious.
One father, who did not want to be named, told the local news service: "It is a disgrace that this could be allowed to happen and we demand more action is taken.
"It could not just be the error or one lady, there must be people at the top responsible too who also need to be sacked. It is an insult to our faith."
Another parent added: "The school have failed the children. How did this meal get into the school system to be fed to the children?
"It's just shocking that dietary requirements haven't been met. We don't know what was actually served. Non-Halal is a very ambiguous term.
"They need to explain what it means but we doubt we are going to get answers."
But father-of-three Barry Jackman, 45, added: "It's a little bit harsh to sack somebody because of one little mistake.
"Yes, we have to respect religions and standards which are expected - but it was a one-off and surely the lady doesn't deserve to lose her job."
School meals in Birmingham are provided by the council department Direct Services.
Sheila Walker, head of Direct Services, wrote to the headmaster last month to confirm the mistake.
She said: "This was found to be due to an error and was unintentional, nevertheless, we have failed to ensure the integrity of Halal only food at Moseley School."
A Birmingham City Council spokesperson added: "We of course apologise for any concerns this has caused.
''We do have robust procedures in place and the caterer successfully provides thousands of meals daily to schools. A letter has been sent to all parents to alert them to what happened."
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