This means that once failed and disgusted, they become uselessly careful ('Atsumono ni koritarumono, ae wo fuku' (Those who were disgusted with a hot soup blow a marinated food or sashimi) means the same).
つまり、一度失敗した事に懲りて無益な用心をすること（「羹に懲りたる者、あえを吹く」と同意。