Twenty-eight female guards were unfairly dismissed by a security company because the client‚ Metrora.
An ex-chef where another cook was fired last week after pieces of glass were found in the food she had prepared claims he experienced the same problem when he was employed at the same Pretoria restaurant.
Sowetan reported on Tuesday that Sarinah Singo, 33, of Lotus Gardens, Pretoria West, was dismissed after pieces of broken glass were found in the lasagne she had prepared.
Hezekiel Mokwape, of Phake, Mpumalanga, said he trained Singo.
He said there was no way she would have intentionally put glass in the food.
"She is the victim of a scam in which somebody puts a foreign object in the food after eating a large portion of it and then insists that the bill be cancelled," he said.
She had nothing to gain by putting glass in that dish and she is a responsible family woman."
Mokwape asked whether management had looked at that day's surveillance recordings.
The restaurant's manager, Vernon Gebhardt, said there was glass in all the the lasagne products Singo had prepared.
"If a customer had intentionally put glass in the food the lasagne still in the kitchen would not have had glass in it," he said.
Gebhardt said she might have been cross with him because they had had a heated argument a few days earlier.
He said that the surveillance camera does not cover the area where food is prepared.
Singo is taking the matter to the commission for conciliation, mediation and arbitration to charge her boss with unfair dismissal.
"I prepared the food and left it in the oven when I knocked off that Monday afternoon.
"I honestly do not know how the glass got in the food. What worries me is that the glass was discovered the same day but I was only informed two days later.
"I was charged and dismissed without any investigation."