OS X V10.6 Snow Leopard :: Exclude Dotted Files From Zip?

How do you make the exclude file option on zip, or unzip, work for dotted files? For example,  

zip -r foo ~/foo/ -x *.txt 

will zip all files in ~/foo/ that do not have the extension txt.  But this doesn't work for "hidden" files, those that start with ".", like ".txt".  So, 

zip -r foo ~/foo/ -x /.txt 

still gets all the .txt files in foo zipped up, not excluded. 

unzip foo -x /.txt 

has the same problem: it happily includes any .txt files in foo.zip in the unzipping

Info:
Mac OS X (10.6.8)