Japanese food experts have developed a food anti-tamper packaging technology. With this technique, as soon as the lid of the food container is opened, the round mark on the transparent lid changes color.
This kind of food anti-tamper packaging technology is: Put a small package of ferrous oxide into the packaging container, and install another oxygen indicator round logo on the transparent bottle cap. Once the bottle cap is opened, the oxygen-deficient atmosphere inside the container is destroyed, and the ferrous oxide is converted into iron oxide, and the color of the round mark also changes.
It is said that this food anti-tamper packaging technology can be applied to granular, powdered, baked and canned foods.