E519 – Cupric sulfate

Description

Blue crystalline solid

Risks

Notes

Copper sulfate is a bright blue crystalline compound made from copper and sulfur combined with oxygen. It's produced industrially by treating copper metal or copper-containing ores with sulfuric acid, creating distinctive blue crystals that dissolve readily in water. While copper sulfate has many industrial uses, the food-grade version is specially purified to meet strict safety standards for consumption. In food processing, E519 serves as both a firming agent and a color fixative, meaning it helps foods maintain their shape and prevents colors from fading or changing. You'll primarily find it in certain preserved vegetables, some pickled products, and occasionally in processed olives where it helps maintain their firm texture and natural green color. It's used in very small quantities due to its potency. This is a synthetic additive that's technically suitable for vegetarian and vegan diets, as it contains no animal products. However, its use in food is quite limited and heavily regulated because copper, while an essential trace mineral our bodies need, can be harmful in larger amounts. Many countries have strict limits on its use, and some have banned it entirely in food applications. Consumers following organic diets should note that E519 is not permitted in organic food production.