Rancidification may be prevented by the following:

• Proper storage of the fats in air-light non-metallic receptacles kept in cool place, away from light, moisture, and warmth. Storing in non-metallic vessels is necessary because metals like copper and lead catalyse rancidity.
• Addition of antioxidants like Vitamin C and E.

Kries test is a delicate test used to detect oxidative rancidity. In this test, the fat is treated with ether, phloroglucinol, and hydrochloric acid. Positive test is indicated by the development of a red colour. This is due to the presence of epihydrin aldehyde, which is one of the oxidation products.