Tests found that samples of the popular Chinese candy sold in four Connecticut stores contain traces of melamine, the chemical responsible for kidney problems in over 50,000 Chinese children when it was mixed with infant formula. Guan Sheng Yuan Co., the producer of White Rabbit, said last week that it halted production of the sweets after melamine was found in the candy around the world. The U.S. Food and Drug Administration also advised that people avoid the candy. In New Haven, the candy is sold at Hong Kong Grocery and at State Fish Farm Market.