As an employee of a national brand manufacturer, I can advise that even if the national brand co. makes the store brand product, the quality of the store brand product can be much lower.
Many national brand companies already sell products under multiple brand names (different quality levels appeal to different market segments). So, it is no problem having a lesser quality for store brand manufactuered product, and a higher quality for the national branded companies product(s).
Many national brand companies already sell products under multiple brand names (different quality levels appeal to different market segments). So, it is no problem having a lesser quality for store brand manufactuered product, and a higher quality for the national branded companies product(s).