Alternate adding each fruit to a juicer. It's best to use green Granny Smith apples. They are the healthiest and Granny Smith's have the lowest amount of salicylates among all the apple varieties. Some kids do well with Granny Smith apples but not with other apple varieties. I really like this juice but I think it was a little too sour for my kids. You can try using Fuji apples to make it sweeter but I think it's good as is. You can also add some grapes for variety.
We use an Omega juicer that I got 10 years ago. This is what Dr. Mercola was recommending back then because the motor is very slow so it does not destroy the vitamins and nutrients like some other more powerful juicers might do. I've used it to make baby food too.
I got this recipe from Donna Pliner Rodnitzky's book.
Feingold Stage 2