Correctly handling Tabs and Carriage Returns with StreamWriter

I have a very simple form which when submitted writes to a text file.
To create a file that cab be opened as a tab delimited file in Excel I am adding tabs between each input filed something similar to this:
objStreamWriter.WriteLine(txtEmail & " " txtMessage & " " & DateTime.Now.ToString())

Everything is writing to the file as it should.  However since txtMessage is a text box, their is to potential to enter a Tab if a user where to copy and paste input from another applicaiton and even more likely they can enter carriage returns.
 When I test with either Tabs or Carriage returns and then open the file in Excel my columns get all out of synch.  I understand that I need to parse the string (I am guessing that i need ot replace tabs or carriage returns) and modify it before it gets written to the text tile.  I am not sure if there are characters that can be used to replace the ori ...