PART OF THE LANDSCAPE: Shao Wan Sheng on East Nanjing Road as it was in the 1910s, and as it is today. [Photo provided to Shanghai Star]

But traditions are hard to keep up.

"As the environment becomes more polluted, there are almost no huangni luo in Ningbo anymore because the creature only lives on clean beaches. Now we have to bring them in from the east pennisula of Liaoning, and even from North Korea," says Fan Fenxiao, general manager of the Shanghai Shao Wan Sheng Food Company.

The production time is around the middle of the fourth lunar month, when the snails are fresh and fat, and devoid of sandy sediments. The sea snails will be salted three times, rinsed with distilled water, and preserved with high-quality rice wine.

The soft, sweet snails, fresh and fat and salty, have won the hearts of many, especially those with their culinary roots in Ningbo and Shaoxing cities. There was a slump in the 1960s and 1970s, but in the mid-1980s Shao Wan Sheng restored production of its famous pickled shrimp sauce, alcohol-preserved whelks, crabs and cooked chicken, as well as meats and fish marinated with distiller’s grains. Production has since been moved to the Pudong New Area.

"We now have more than 10,000 square meters of space in Kangqiao in Pudong New Area, which is 100 times larger than that in 1985," says Fan. The Nanjing Road store’s revenue has grown at a rate of 20 percent year-on-year since 1999, and it reached 120 million yuan ($19.5 million) in 2013, according to Fan.

A growing number of Shanghai people are living in suburban areas as a result of the city’s urbanization. To meet that trend and cater to customers, Shao Wan Sheng started 12 franchises across the city in Baoshan, Pudong and Yangpu districts. Two more are in the pipeline.

"A 400-square-meter store will open in Yangjing in Pudong by the end of this year, and another branch will start in Baoshan next year," says Fan. Shao Wan Sheng has also developed new products.

In April this year, a 2,000-square-meter production space was used for producing traditional breakfast foods including stuffed buns, fried dumplings and steamed dumplings.

A contract for cooperation was signed in July with a Taiwan-based company which specializes in making vegetarian food.

"The food will be made from organic beans and taste like dried beef or pork," says Fan, adding that production will start in a couple of months.

To supplement its range of drunken products, sold from November to April due to seasonal and regulatory factors, Shao Wan Sheng is also looking to launch a new series of cooked food products marinated in distiller’s grains in August.

"These products wil be packed in specially made containers that can extend the shelf-life to 10 days, and the portions can serve a family of three."