The blue liquid box that comes with a refrigerator is typically a product called "FreshFlow™ Produce Preserver." This is a special technology developed by Whirlpool Corporation (and may be present in some other refrigerator brands as well) to help extend the freshness of fruits and vegetables stored in the refrigerator's crisper drawers.
The FreshFlow™ Produce Preserver works by absorbing ethylene gas, which is a natural gas produced by certain fruits and vegetables as they ripen. Ethylene gas can accelerate the ripening process and cause nearby produce to spoil faster. By using the FreshFlow™ Produce Preserver, the ethylene gas is neutralized, helping to slow down the ripening of fruits and vegetables and extending their shelf life.
The blue liquid inside the box is a mixture of potassium permanganate and water, which is the active ingredient responsible for absorbing the ethylene gas. Over time, the liquid will change color, indicating that it's time to replace the Produce Preserver. The frequency of replacement varies depending on the refrigerator model and usage, but it's usually recommended to change it every six months.
To use the FreshFlow™ Produce Preserver, simply place the blue liquid box in the designated holder or compartment in the refrigerator, often located in one of the crisper drawers or a nearby area. Follow the instructions provided by the refrigerator manufacturer for the specific model you own.
Please note that not all refrigerators come with this technology, and it's mainly available in higher-end or newer models. If you are unsure about the purpose of the blue liquid box in your refrigerator, consult the refrigerator's user manual or contact the manufacturer for clarification.