My son is going to be 7 months in about a week and he has been on solids since he was 4 months old (only rice cereal until 6 months) and had complications with his bowels since he was 5 1/2 months. He is also strictly breast fed, never used formula. When I went to his 6 month check up I had talked to his pediatrician about it and she said it was normal. That babies tend to have changes in their bowels when adjusting to new foods. She told me to stop with the rice cereal and try oatmeal cereal instead, which seems to be much easier for him to pass. Also, she had said that the green veggies were more loosening than the others so maybe try some green veggies to help things along. He has started to regulate a bit, with one bowel a day, still massive, but it seems to be getting better for him. He was straining at the beginning and now he isn't making the strain sound anymore and things are starting to get easier for him to pass.
Obviously, making your own pureed veggies and using organic will be better for him anyways, so that would be a good route to go as well.
But don't worry too much, things should get better for her as her tummy gets used to the different foods.
Oh and the other thing his pediatrician said was to try one veggie at a time for 4-5 days, then switch to another veggie until he has tried 4 or 5 veggies, then go to fruits and do the same system. This will get your baby used to each veggie & fruit separately, you can see how their body reacts to each item and then once they have tried 4-5 veggies and 4-5 fruits you can begin to mix things up a bit. It sounded like a good system to us, so that's what we have been doing and I think it works pretty well.
The other thing was if she is struggling to try a little apple juice or prune juice. I gave my son prune juice (tablespoon) with 2 tablespoons water, but he wasn't a fan of the prune juice so it was hard to get him to drink it. Then we tried apple juice and he seemed to be more tolerant of it. I gave it to him in his sippy cup and let him try to sip it himself (I helped a little). And when he wouldn't quite get it that way since he isn't too fond of the bottle, I used a syringe and squeezed some into the side of his mouth to ensure that he got some.
Hope this helps...good luck...don't worry, I checked with my son's pediatrician and she didn't seem to think anything was odd with the way things were going.