Separate multiple comma separated values in Numbers
Here is a suggestion from https://discussions.apple.com/message/26532955#26532955


  In order to import comma-separated CSV into Numbers.app properly, you need to set the decimal separator to period in System Preferences. If decimal separator is set to comma, Numbers.app can only import semicolon-separated CSV.
  
  
  Quit Numbers.app;
  Set the decimal separator to period, temporarily, in System Preferences; [/Language &amp; Region/Advanced]
  Launch Numbers.app, import the CSV file and save the resultant Numbers file;
  Quit Numbers.app;
  Reset the decimal separator to the original (presumably, comma) in System Preferences;