The supermarket is planning to wash all its bagged salads in spring water prior to packing; most packaged salads are currently washed in chlorinated water to remove soil and ensure that they are safe to eat.
Sainsbury's is redesigning its existing packaging to draw attention to the modification to promote the change.
The new system will be launched across the supermarket's salad range, which comprises nearly 30 bagged salads, over the next 12 to 18 months.
The move follows Sainsbury's overhaul of its healthy Be Good to Yourself range in January, when it developed 150 new product lines and packaging as part of a drive to increase sales.