No new food poisoning case has been recorded since the Centre of Food Safety recently banned the import and sale of Horng Ryen Jen sandwiches.
Secretary for Food & Health Dr Ko Wing-man said although new clusters were still being identified recently, the people involved purchased or consumed the sandwich before the ban was imposed.
The centre has also traced three importers and more than 100 Taiwanese food retail outlets, and found no Horng Ryen Jen sandwiches on sale.
Contamination can happen during the production, import, retail or storage stages, he said, adding the Centre for Health Protection and the Centre for Food Safety will investigate the contamination source.
The Government will also review the regulation on informal food import channels, such as online purchases, to formulate more effective means to control and regulate this type of import in future, he added.
Meanwhile, the Centre for Health Protection announced tonight that one more food poisoning cluster related to the sandwich, involving two women, has been identified, bringing the total to 30 clusters with 86 people affected.
