There may be many reasons why Wujiang Fuling mustard cannot be found in supermarkets. One possibility is supply chain and production issues, resulting in insufficient supply. In addition, it may also be due to fierce market competition that other brands of pickled mustard occupy most of the market share, resulting in a decrease in the sales share of Wujiang Fuling pickled mustard in supermarkets. In addition, it may also be because consumers have reduced demand for Wujiang Fuling mustard and are choosing other brands or healthier foods.

Specific reasons may require further understanding of market conditions and supply chain conditions. If you are interested in Wujiang Fuling mustard, you can try to contact the manufacturer or supermarket for more information.