The foam is really strange.  Did you wash your tomatoes in soap and not get all the soap washed off.  Is the foam still on the tomatoes after the jars have cooled?  Sometimes if they were processed in a pressure canner or in a boiling water canner and the water was at a full rolling boil they will foam a little,  but you have a lot,  and it should dissipate once the jars cool.  Also when did you process your tomatoes?  

I would suggest you call the OSU Food Preservation Hotline at <personal data hidden>.  Certified Master Food Preservers are available M-F from 9 am-5pm. to answer your questions.  They can ask you questions about how you canned your tomatoes and help you determine why the foam might be on the top and if they are safe or not.  .  

OR     please send me more information including the variety, how you prepared them for canning and what method you used.  Hot pack or raw pack, did you add lemon juice or citric acid and for how long did your process them.  

Thanks for using Ask an Expert

Nellie Oehler

I processed raw pack for 45 min. In full boiling hotwater bath yesterday, so the jars are cold now when I took the picture today.  I didn't wash the tomatoes in soap, they are regular canning tomatoes from thistledown.  Added lemon juice to the jars.  

I will most likely dump the contents, don't want to chance it.  But I'm curious as to the cause of bubbles.  Thanks for this hotline and quick response!!  

Jean 

Hi Jean,
Were these quarts and did you use the raw pack with water added?  If so then it should not be a safety issue.  Shake the jar and see if the bubbles go away.  You might have had the water boiling too fast and they bubbled a lot in the jar.  You did everything right if you used the water pack so I wouldn't worry about the safety of the tomatoes.  Do shake them and see if the bubbles go away.  

Nellie

Nellie
I did shake the jar, bubbles remained.  I did discover what appears to be a crack in the middle of the glass if that's possible...  i decided to discard the tomatoes and jar!  

thanks for you help!!  

jean

Thanks for the update.  You are probably wise to throw them out.  The jar could have been the problem.  Strange things happen sometime for no reason so don't let it discourage you.  You did everything right.  Happens to all of us.  
I always go by the motto "When in Doubt Throw it Out.

Good luck with the next batch.

Nellie