Supermarket chain Sheng Siong has apologised after a customer found a number of large maggots wriggling in a carton of quail eggs last Tuesday.

The incident comes less than two months after a customer found several maggots in a carton of quail eggs he bought from FairPrice.

And in January this year, another customer was given a refund after finding maggots in the live crabs he bought from FairPrice Finest.

Footage of the most recent incident was uploaded to citizen journalism website Stomp yesterday.

The customer, who wanted to be known only as Amy, told Stomp that she bought the eggs - which were due to expire last Friday - from a Sheng Siong outlet at Junction Nine mall in Yishun on April 11.

When she opened the carton to cook the eggs last Tuesday, however, she spotted "big, fat maggots" wriggling next to one of the eggs.

Amy said that the incident left her "shocked and disgusted", and added that she threw the whole carton away.

Yesterday, a Sheng Siong spokesman told The Straits Times that the chain has offered Amy a refund, and was grateful that she brought the incident to its knowledge.

The spokesman said Sheng Siong conducted a thorough check of the quail eggs on its shelves immediately after receiving Amy's feedback, and will be working with its egg supplier to look into the incident.

He added that given the fragile nature of eggs, any crack in an egg's shell may result in an infestation.

"As we value food safety and quality, we encourage customers to reach out to us when they encounter similar incidents," he said.

On its website, the Singapore Food Agency advises consumers to look for eggs with clean shells when making their purchases, and to handle them carefully.

Consumers are also advised not to buy eggs that have cracked shells as the eggs may be contaminated with bacteria.