hey Ann ... great question. I too love Aldi's for things like non-perishables and cheeses tho a small collection. I've just gotten into (again) my own yogurt and YoChee (Yogurt Cheese) making and almost always use only nonfat powdered milk for just about everything cuz I don't drink it maybe ... I use it in cooking, sauces, smoothies, etc.
Aldi's, as far as I know is a German Company that has been around for a long time and is still expanding internationally. I've never had a problem in trusting German made products. Of course their produce doesn't come from Germany or so I am assuming and some of it is par with and even better than the more expensive competitors. Given their selection, I've not had any difficulty with their produce section lately.
Like other ladies have mentioned here, I go to Aldi's first and for what I can't find there, I go to Rainbow or Cub.
I must admit that I also shop at Restaurant Depot for QUANTITY needs: spices, cheese blocks, dairy, juices, vinegars, blah blah blah... but this is like a Sam's club only geared to Food and Food Service accessories. And the only reason I use this 'club' is because I cook for Loaves and Fishes to feed between 300 and 900 people at a time. I do pick up some items for my own use and then move on to Aldi's for the rest for my 'many meals' as I call them. I have 3 1/2 hours to prepare from scratch with a staff of volunteers and one hour to serve. I love it.
I don't know that I've said anything useful here but Aldi's is always my first stop when I'm NOT feeding hundreds at one time.
Also, for anyone reading this ... for fun, should you want information about making and using yogurt and yogurt cheese to replace cream cheese, sour cream, creme fillings, mayonnaise, dips, etc. let me know ... it is so fun and the cheese mixtures freeze beautifully so that you can stock up and have something wonderfully in a hurry ... yummm, a YoChee Alfredo Sauce, and artichoke spinach dip ... possibilities are unlimited ... and the healthiest we can eat.
Bon Appetit ...