Are these safe for a two year old? And do children typically like the flavor?

I am looking for a probiotic for my 5 year old. Would this be recommended?

Anyone tried this? I need to get my son some

What is the youngest age this is safe for?

I would like to know which stores carry the Yum-V's Probiotic? I received a sample but I can not seem to find them at my local Walmart. So I am curious if you may have a list of stores that carry them or if it's just easier to order online? Thank you!!