Fast judging method for DMF of mildew preventive

The invention discloses a fast judging method for DMF of mildew preventive. The method comprises the steps that firstly, an appropriate amount of fodder mildew preventive to be detected is weighed and placed in a detection container; secondly, a condenser pipe is additionally arranged at the upper end of the detection container, water is injected and condensed, and the detection container is bathed in a water bath kettle at the temperature ranging from 90 DEG C to 102 DEG C for 1-3 h; thirdly, after water bathing, whether there is a white needle-shaped crystal at the lower end of the condenser pipe or not is observed, if not, it is proved that a sample does not contain DMF, and if yes, the sample is suspected to contain the DMF. Devices used in the method are familiar and easy to obtain, and additive is not needed. The operation is easy, the DMF can be rapidly detected, the accuracy can reach more than 95%, and the method is particularly suitable for a feed mill to detect the fodder additive before the fodder additive enters the feed mill.