Can you exclude a URL from mod_deflate gzip rules?

I have added the following code in my .htaccess file:

<ifmodule mod_deflate.c>
AddOutputFilterByType DEFLATE text/text text/html text/plain text/xml text/css application/x-javascript application/javascript
</ifmodule>

However, I have one URL “http://www.example.com/foo/” that doesn’t behave well when gzipped.

This is for a wordpress site, so the /foo/ isn’t a real folder/directory — it’s just the permalink slug. I’ve found the following code to exclude folders but I can’t get it to work and I think it’s because /foo/ is not an actual directory?

 SetEnvIf request_uri ^/foo(.*) no-gzip dont-vary

Is there a way to exclude any URL that contains /foo/* from being deflated?

Thank you!