E529 · Calcium oxide
- WHO
- Safe
- FDA
- Safe
- EFSA
- Safe
- FSANZ
- Safe
- Japan
- Safe
- UK FSA
- Safe
- Health Canada
- Safe
What is E529?
Calcium oxide (E529), also known as quicklime, is used in food processing as an acidity regulator and processing aid, for example in sugar refining and in some baking applications. In water it converts to calcium hydroxide, and residual levels in finished food are low.
Also appears on labels as: Calcium Oxide, CaO, Quicklime, Burnt Lime, Lime, Calcined Lime, Unslaked Lime, Calx, Calcium Monoxide, Calcium Oxide (E529), Calcium Oxide CAS 1305-78-8, Food Grade Calcium Oxide.
What the evidence says
- Generally recognized as safe at typical food-use levels; concentrated quicklime is caustic and reacts strongly with water, but this is a handling concern for manufacturers, not a risk from trace amounts in finished food.
Research behind the verdict
- Calcium Oxide in Food Processing: Regulatory Framework and Safety Evaluation — FDA Regulatory Compliance Team, Code of Federal Regulations - Food Safety Standards (2024). A regulatory assessment of calcium oxide (E529), also known as quicklime, examining its approved uses as a firming agent, flour treatment agent, and pH regulator. The FDA evaluation confirmed calcium oxide meets safety requirements under CFR Title 21 when used according to specified guidelines. The study noted its historical use in food processing and confirmed adequate safety margins for approved applications. The research supports its continued use in specific food categories including baked goods, dairy products, and processed foods under proper handling procedures.[safe]
Frequently asked questions
Is E529 safe?
Our overall verdict for E529 (Calcium oxide) is “Safe”, based on the most cautious of the major regulators’ positions — FDA: safe; WHO: safe; EFSA: safe; FSANZ: safe; Japan: safe; UK FSA: safe; Health Canada: safe.
Is E529 vegan, halal or gluten-free?
According to our ingredient data for Calcium oxide — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E529 and why is it used?
Calcium oxide (E529), also known as quicklime, is used in food processing as an acidity regulator and processing aid, for example in sugar refining and in some baking applications. In water it converts to calcium hydroxide, and residual levels in finished food are low.
Does E529 contain allergens?
No known allergens are recorded for Calcium oxide.
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.