Is $3m too much for a family recipe in Singapore?

"These last few years I haven't had as much energy, because I've been standing up for nearly 40 years, running this business," says Betty Kong.

Ms Kong and her husband Ha Wai Kay had the same routine every day. They would wake up before dawn and journey to their roast meat shop to start the day's cooking.

Drawing on a secret recipe inherited from his father, Mr Ha would be in the kitchen taking care of roasting the pork and duck, while his wife would prepare the front of house.

From around 11am, customers would start pouring into their modest eatery and would keep coming until closing time after sunset.

Mr Ha started out roasting meat in a small stall in Singapore's Chinatown, but over time the business grew and they moved to a small shop, naming the Kay Lee Roast Meat Joint.

In 2012, at almost 70 years old they decided it was time to retire. But it was only two years later that their fortunes suddenly changed.

In October, a Singapore conglomerate, Aztech, paid $3m (4m Singapore dollars) for their business. And it was largely because of their secret roast meat recipe.

Aztech's founder Michael Mun had tried Kay Lee's roast meat and decided that if he liked it so much then there was a good chance many more people would too.

"We usually have management meetings over lunches," says Michael's son Jeremy, vice president of marketing at Aztech, "and one of the senior managers mentioned this shop was up for sale."

Hoping it was onto a winner, Aztech bought Kay Lee Roast Meat Joint.

Besides the family recipe, the value of the land the roast meat shop was sitting on was also important. Aztech offered the couple $370,000 more than their original asking price because land prices had risen significantly during the intervening period.

Aztech which is also a family business specialises in electronics, and LED lighting. More recently its moved into food distribution and says it has big plans for the roast meat business.

There are now two outlets for the Kay Lee Roast Meat brand. Aztech has also invested in a new centralised kitchen, where all the cooking is done before the food is transported to the various outlets.

As part of the sale agreement, Mr Ha and his wife remain temporarily employed by Aztech, to train the new staff on ways to perfect their family recipe.

Singaporeans love their food. They can spend hours debating on the best places on the island to go to for their favourite dishes, ranging from the spiciest laksa (noodles in coconut broth), to the tastiest of chilli crabs.

Many families dine out at least once a week, often at small restaurants that focus largely on selling staple food dishes.

Aztech's purchase of Kay Lee Roast Meat Joint has raised the hopes of others in the food industry yearning for a break.

At The Bedok Marketplace, a newly renovated hawker centre to the east of Singapore there is a small stall called Uncle Chicken Rice, operated by a second-generation food business owner Niven Leong.

His prized chicken rice recipe was also handed down from his father, who started out with a small food stall in 1971 in one of Singapore's residential estates.

Mr Leong's family recipe is on the market as well, for around $32,000. It is a price tag includes training and a handover process.

He is pinning his hopes on finding a passionate, enthusiastic and energetic "hawkerpreneur" (the local term given to an entrepreneur working in one of Singapore's many hawker centres) to take over the business.

"I think if they can see the potential in our chicken rice my job is done - my father's legacy can carry on," says Mr Leong.

He says that he and his wife do not have children. "We don't have someone to pass this on to and it would be a great pity if this recipe is gone."

Carrying on this kind of family legacy is easier said than done. Generally, Singapore's younger generation is not keen to spend long hours cooking over a hot stove for little financial reward, when there's money to be made elsewhere.

Yet Mr Leong is confident that he has one of Singapore's best chicken rice recipes and remains optimistic that one day someone will come along who shares his passion.

Until that day he says he'll keep selling his chicken rice seven days a week, just as his father did before him.

As for Betty Kong and Ha Wai Kay, they are looking forward to retiring - as soon as they've passed on all their trade secrets to Kay Lee Roast Meat Joint's new owners.