Can you use aluminum can for retortable products?

The simple answer is yes - Aluminium is in regular use for retort packs. You can find retorted packs of petfood (the small square foil-lidded trays) which are all aluminum and you'll also fins some aluminum cans of pate, fish etc all of which are retorted.. The tendency to use steel cans has been, I think, more to do with cost than suitability so cans would be equally good. Plastic materials are also used in retort applications, paticularly in pouches. Once again, you'll find petfood, soups and sauces in this style but they're also the pack of choice for military rations as they're flexible, compact and easy to reheat.