Originally, the Zugot were in Consumption of Eggs, Cucumbers, and Nuts; there was a Fourth, and all of the other Zugot are a concern because we don't know the Fourth: Pesachim 110b
In Israel they weren't careful about Zugot: Pesachim 110b
One who is concerned against Zugot will be in danger from them, but people should still be a little careful: Pesachim 110b