A supermarket has apologised after a student found a park sausage roll in a packet of vegetarian pastries.

The student cannot eat the meat on religious grounds, so she said she was appalled when she opened the opened the packet of cheese and onion rolls and found one contained meat.

Supermarket staff have since apologised, but the company said it cannot understand how it happened after carrying out detailed investigation.

It said only cheese and onion rolls had been processed on that particular production run, and the one previous to that, and there had been no other complaints.

The 20-year-old, who is studying optometry at the University of Bradford, bought the pack of ten 'Chosen By You' branded cheese and onion rolls at Asda in Cemetery Road, Lidget Green.

She said: "This is not acceptable. I'm a Muslim so wouldn't eat sausage rolls, but what about vegetarians too?

"Vegetarian labelled packing should contain vegetarian food.

"I complained to Asda asking them to check their production lines, but they told me it will take up to 40 days to respond to the complaint. When I rang they didn't say anything about checking the store and taking any more off the shelves.

"I'm concerned that other people could have eaten one by mistake."

She said she realised the filling was the wrong colour after she cooked the roll in a microwave, but spotted the error before she had taken a bite.

A spokesman for Asda said: "We’re at a loss to understand how this happened and are confident this is an isolated incident.

"We’re sorry for any upset caused and we’ll be in touch with her shortly with the details of our full investigation."