This document discusses potassium bisulphite as a food preservative. It describes how potassium bisulphite prevents microbial growth through the release of sulfur dioxide. Experiments were conducted to study the effects of varying concentration, temperature, and time on potassium bisulphite's preservative properties in fruit jam. The results showed that increasing concentration, lower temperature, and shorter time periods enhanced its effectiveness at preventing spoilage. Potassium bisulphite is a commonly used food preservative that helps extend the shelf life of various products.