Irish Lass,
Did a quick check of the Aldi website. Aldi has some generic information for consumers and their supply chain. They probably give you a lot more as one of their suppliers. If you are supplying food or beverage products you will not go wrong with a GFSI bench-marked program such as BRC or any of the other GFSI recognized programs. If you are referring to social responsibility audits, some requirements can vary from country to country depending on national/local labor laws. SA 8000 is a good place to start to build a decent social responsibility program as long as you remember to plug in local labor law requirements and Aldi code of conduct requirements.
Good luck!