What is E526?

Complete guide to understanding calcium hydroxide in your food

The Quick Answer

E526 is calcium hydroxide, commonly called slaked lime or quenched lime.

It’s used in food production to regulate acidity, fortify with calcium, and stabilize products.

Most people consume it regularly in dairy products, processed foods, and traditional corn-based dishes without realizing it.

What Exactly Is E526?

E526 is calcium hydroxide (Ca(OH)₂), a white powder made by combining calcium oxide (quicklime) with water.

The process is simple and ancient: limestone (calcium carbonate) is heated to high temperatures to produce quicklime, then water is added. This produces slaked lime—calcium hydroxide. The reaction releases heat and is exothermic.

Calcium hydroxide has been used for thousands of years in food preparation, particularly in the traditional nixtamalization process for corn—a technique still used today to make tortillas, corn flour, and other corn-based products. This long history of use supports its safety profile.

In technical terms, it’s a strongly alkaline (opposite of acidic) compound with low water solubility.

Where You’ll Find E526

E526 appears in numerous foods, especially dairy and processed items:

– Dairy products and cheese
– Powdered and condensed milk
– Butter and whey products
– Fat spreads and emulsions
– Sweet creams and ice cream
– Processed and preserved fruits
– Vegetable products
– Meat and fish products
– Soups and broths
– Sauces and salads
– Bakery, pastry, and confectionery products
– Corn flour and tortillas (nixtamalization)
– Parboiled rice and pasta
– Food supplements
– Alcoholic and non-alcoholic beverages

If you’ve eaten processed cheese, ice cream, processed meats, or corn-based products, you’ve likely consumed trace amounts of E526.

Why Do Food Companies Use E526?

E526 serves multiple critical functions in food production.

First, it’s a powerful acidity regulator. By neutralizing acids and adjusting pH, it extends shelf life, prevents spoilage, and maintains optimal taste and texture. Without pH control, foods develop unpleasant flavors and spoil faster.

Second, it provides bioavailable calcium—a mineral essential for bone and dental health. Foods fortified with E526 contribute meaningfully to dietary calcium intake.

Third, it stabilizes products. In ice creams, puddings, and other creamy products, it prevents separation and maintains consistency.

Fourth, it cures and preserves. In egg preservation and meat products, it helps maintain quality.

Fifth, in corn products, it performs nixtamalization—a process that not only improves taste and texture but actually increases the nutritional bioavailability of niacin (vitamin B3) in corn. This is why traditional corn-based diets, when prepared with nixtamalization, provide better nutrition than untreated corn.

Is It Safe?

Regulatory authorities confirm E526 is safe for food use.

The FDA approves it, the EFSA authorizes it under Commission Regulation (EU) No 231/2012, and WHO’s JECFA approves it. No Acceptable Daily Intake (ADI) was established—which indicates no safety concern at approved food use levels.

Calcium is an essential mineral for human health. The Upper Intake Level (UL) for calcium is set at 2,500 mg per day—far above typical food additive consumption. Food-grade E526 contributes small amounts of bioavailable calcium to the diet, well within safe limits.

E526 is used under “Quantum Satis” authorization, meaning manufacturers use only necessary amounts with no absolute maximum specified.

Occupational Hazards vs. Food Safety

It’s crucial to understand the difference.

Industrial workers handling concentrated calcium hydroxide powder face serious hazards:

– Severe skin irritation or burns
– Eye damage including corneal opacity
– Respiratory tract irritation
– In concentrated ingestion: gastrointestinal burns

However, these hazards apply to workers in factories handling pure, concentrated powder—not to consumers eating foods containing trace amounts of E526.

Food-grade calcium hydroxide is used in small quantities and is further diluted during manufacturing. By the time food reaches your table, any E526 presents no irritation or safety risk. The pH shift caused by trace amounts is physiologically irrelevant.

The Unique Nixtamalization Process

One distinctive use of E526 is nixtamalization—an ancient food preparation technique.

Corn is soaked or cooked in a calcium hydroxide solution. This process, used for thousands of years in traditional cooking and still used today, serves multiple purposes:

– Improves texture and taste of corn products
– Increases nutritional bioavailability of niacin (vitamin B3)
– Makes calcium more available in the corn
– Easier grinding and flour production
– Enhanced food safety properties

This traditional use demonstrates the long safety history of food-grade calcium hydroxide and shows that it can contribute nutritional benefits to foods.

Calcium Content and Nutrition

E526 can fortify foods with bioavailable calcium.

Calcium is essential for bone health, dental health, muscle function, and numerous physiological processes. The Upper Intake Level for calcium is 2,500 mg per day. Food-grade E526 provides bioavailable calcium in quantities that contribute safely to daily intake.

This dual function—serving both as a pH regulator and a nutritional supplement—explains why regulatory agencies widely approve it.

Processing Aid vs. Food Additive

An important distinction affects labeling.

Calcium hydroxide can serve as either:

– Processing aid: If removed during food processing, it doesn’t require label declaration and is called a “technical additive”
– Food additive: If retained in the finished food, it must be declared as “Calcium hydroxide” or “E526”

For example, in sugar refining, calcium hydroxide cleans impurities but is removed before sugar reaches consumers. In other products, it remains and must be declared.

Manufacturing and Source

E526 comes from limestone, a natural mineral.

The manufacturing process is straightforward: limestone (calcium carbonate) is heated to produce quicklime (calcium oxide), then water is added to create slaked lime (calcium hydroxide). This ancient chemical process has been used for centuries in construction, agriculture, and food production.

Food-grade E526 meets strict purity standards and must be free from contamination.

Historical and Organic Approval

Calcium hydroxide isn’t a modern food chemical. It has a centuries-long history in food preparation. Additionally, the European Union has recognized it as an essential substance approved for use in organic farming—reflecting the highest level of safety and naturalness standards.

Differences from Related Hydroxides

Don’t confuse E526 with other hydroxide additives:

– E526 Calcium hydroxide: Calcium + water (slaked lime)
– E529 Calcium oxide: Calcium + oxygen (quicklime)
– E527 Ammonium hydroxide: Ammonia + water
– E528 Magnesium hydroxide: Magnesium + water
– E525 Potassium hydroxide: Potassium + water

These are all different compounds with distinct uses and safety profiles.

Vegan, Vegetarian, and Allergen Status

E526 is suitable for:

– Vegan diets ✓
– Vegetarian diets ✓
– Gluten-free diets ✓
– Those with most allergies ✓

Calcium hydroxide is mineral-derived with no animal products or byproducts involved.

The Bottom Line

E526 (calcium hydroxide) is a naturally derived mineral additive used for acidity regulation, calcium fortification, and food stabilization.

Regulatory authorities worldwide classify it as safe for approved food uses.

At trace amounts found in dairy, processed foods, and corn products, E526 poses no documented health risks.

While concentrated calcium hydroxide has serious occupational hazards, these don’t apply to consumers eating foods containing approved amounts of E526.

Its approval in organic farming and thousands-of-years history in food preparation support its safety and naturalness.

As always, food labels must declare E526 when retained in the final product, enabling informed consumer choice.