Chia Pet grass safe?

I got a cat chia pet for Christmas, and was wondering if the grass it came with is actually safe? I know it says it is, but not everything is accurate. I think is wheat and oat grass, although I am not sure. It has not sprouted yet, so my babies haven't eaten any yet. Also, is the dirt it comes with safe? Gizmo has a tendency to eat soil/dirt. I would like to know if we should change the dirt when the grass dies, and we plant catnip instead.

I tend to get my grass seeds from a trusted organic supplier and plant them in soil that is sold specifically to plant vegetables. Having said that I've looked at Amazon and wiki and I can see nothing that would worry me. The firm is out of San Fransisco and doesn't have any sort of controversy surrounding it. The unhappy reviewers seem to be upset that it either didn't germinate or the end result did not look like the picture on the cover.

The probable reason for both wheat and oat grass is because although most cats like wheat it can be too rich for some, oat grass may be preferable to these cats.  

Alright, thanks. I am glad they will be alright. I can just never be too careful when feeding odd things to my cat!