One of these is sodium bisulfite, also known as sodium hydrogen sulfite or E222. When a small amount is added to packaged potato chips, it prevents the potatoes from browning and inhibits the growth of bacteria that can lead to spoilage. It serves the same purpose with instant mashed potatoes and packaged shrimp. What's slightly alarming is that sodium bisulfite is also used in household cleaning products. In larger quantities, it's an active ingredient in dish soap, laundry detergent, and stain removers.