http://www.dadooda.com/index.cfm/fa/...ibrary_ID/6046

See photo of problem above.

90% of my plum tomatoes have an internal problem - blackening - appear
to be going rotten. There is nothing wrong with the taste away from
the blackened area - other than there isn't much!!

There is no indication of any problem from the outside whatsoever -
they appear to be in perfect condition.

Ideas please.