I know this is an old thread, but since I recently was looking for similar information, I thought I'd post what I found here.
You can grab the RSS feed for new reviews using this pattern:
https://itunes.apple.com/<countryCode>/rss/customerreviews/id=<appId>/sortby=mostrecent/xml
Then you can either send it through IFTT to get an email or add it to you chat tool of choice.