These test strips are used to test low level residual concentrations of peracetic acid used in winemaking and other applications.
Wet the test pad at the end of the strip with deionized water & press against the skin of the fruit, vegetable or poultry in question. If there is any residual peracetic acid, the color of the test pad will change immediately. Compare this to the color chart on the bottle.
Note(1): Bottle is lined with a desiccant to ensure long shelf life. If properly stoppered, strips have a 2 year minimum shelf life & no explicit expiration date.
Note(2): 100 strips per bottle is stated but this is approximate.