Three kinds of food additive citric acid were produced by (1) TRPO, (2) by TBP and (3) by the calcium salt method. Their LD50 were 8250 mg/kg, 12 100 mg/ kg and 6520 mg kg respectively, in female rats when the drug was administered by gayage.

• 柠檬酸(1)、(2)、(3)分别由三烷基氧膦(TRPO)萃取法、磷酸三丁酯(TBP)萃取法和钙盐法生产所获产品,其对雌性大鼠经口的LD_(50)分别为8250 mg/kg、12 100 mg/kg、5620mg/kg,均属实际无毒类食品添加剂。