Results of test samples taken from a Hong Kong-style dim sum chain that was shut down last week over food safety concerns have found Salmonella to be present on some of the restaurant’s cakes.

Shanghai Daily reports that the Shanghai Food and Drug Administration (SFDA) ordered LIST to immediately shut down all nine of its chain restaurants, as well as its central kitchen.

This demand for hygiene testing came after customers who ate at the popular chain’s establishments complained of gastrointestinal discomfort after eating. 

At least 71 people suffered from food poisoning and received treatment at nearby hospitals. Most of the diners developed symptoms between July 16 and 18, though all are now said to have recovered. 

Further tests will be conducted on more food samples as the investigation continues, and SFDA has warned of “severe punishment” for the chain once the investigation is complete.