mime type for CSV files incorrectly detected as text/plain

Mime type autodetection returns "text/plain" for CSV files, for example:

% tika -m foo.csv
Content-Encoding: ISO-8859-1
Content-Length: 78
Content-Type: text/plain; charset=ISO-8859-1
resourceName: foo.csv

This occurs regardless of whether the filename has the appropriate *.csv extension or not.