When did purple dried beancurd in Kaizhou District of Chongqing become intangible heritage?

20 15. As a local specialty food brand, Zishui dried beancurd in Kaizhou District of Chongqing is a specialty of Kaizhou. 20 15-year-old dried beancurd has become an intangible cultural heritage protection project in Chongqing, and has participated in various food festivals and local products exhibitions inside and outside the region for many times. After being passed down from generation to generation in the late Qing Dynasty to the early Republic of China, purple water tofu has high cultural value, nutritional value, scientific and technological value and economic value.