Does Honey Lose Antibacterial Properties When Heated?

January 11, 2026 •

4 min read

Multiple studies have shown that honey possesses significant antimicrobial activity due to a complex interplay of its unique components. However, a common question arises regarding how stable these beneficial properties are, particularly when exposed to heat, a process often used in cooking and commercial pasteurization.

Quick Summary

Heating honey, especially at high or prolonged temperatures, can cause it to lose many of its antibacterial properties. This is due to the degradation of key heat-sensitive compounds like enzymes and certain phytochemicals. The severity of the loss depends on the temperature and duration of heating.

Key Points

Heat degrades enzymes: Honey's hydrogen peroxide-producing enzymes are heat-sensitive and are largely destroyed during high-temperature heating, such as pasteurization.
Manuka honey is more heat-resistant: The primary antibacterial agent in Manuka honey, methylglyoxal (MGO), is more heat-stable than the enzymes in most other honeys, though high heat will still reduce its potency.
Osmotic effect remains intact: Honey's high sugar content and low water activity, which dehydrates bacteria, is a physical property that is not affected by heat.
High-heat cooking is most damaging: Excessive or prolonged heat, like in baking, causes the most significant loss of honey's therapeutic compounds.
Raw honey is best for medicinal use: For maximum antibacterial benefits, it is best to use raw, unpasteurized honey in applications that do not involve high temperatures.
Adding to warm liquids is safer: To preserve benefits in hot drinks, let the liquid cool slightly before adding honey to avoid destroying sensitive enzymes.

The Science of Honey's Antibacterial Power

To understand how heat affects honey, one must first grasp the multifaceted nature of its antimicrobial action. Honey’s ability to fight bacteria is not due to a single compound but a synergy of several factors working together.

Key Components of Honey's Antibacterial Activity

High Sugar Content and Low Water Activity: Honey is a hypertonic solution, meaning its high sugar concentration draws water out of bacterial cells, causing them to dehydrate and die. This osmotic effect is a fundamental antibacterial mechanism that is largely unaffected by heat.
Acidic pH: With a typical pH ranging from 3.2 to 4.5, honey's natural acidity creates an unfavorable environment for the growth of many bacterial pathogens. This acidic nature is relatively stable against moderate heat.
Hydrogen Peroxide: When honey is diluted, the enzyme glucose oxidase, secreted by bees, produces hydrogen peroxide. This is a potent antiseptic, but the enzyme that produces it is highly heat-sensitive and is easily destroyed by heating.
Phytochemicals: Honey contains a variety of plant-derived compounds, including phenolic acids and flavonoids, which contribute to its antioxidant and antimicrobial effects. The concentration and type of these compounds vary with the honey's floral source. While some phenolic compounds are more heat-stable, many are susceptible to degradation at high temperatures.
Methylglyoxal (MGO): This compound is responsible for the unique, powerful non-peroxide antibacterial activity found in Manuka honey. MGO is formed from dihydroxyacetone (DHA), which is present in the nectar of Manuka flowers. MGO is much more heat-stable than the glucose oxidase enzyme found in other honeys, which is why Manuka retains more of its potency when heated.

The Impact of Heating on Antibacterial Properties

Heating honey, whether for pasteurization or cooking, diminishes its antibacterial effectiveness by breaking down several crucial, heat-sensitive components. The specific effect depends on the temperature and the duration of heating. For most honeys, the loss of antibacterial action is primarily due to the destruction of the glucose oxidase enzyme, which eliminates the hydrogen peroxide mechanism.

In a study, Bangladeshi honey samples heated to 50ºC, 70ºC, and 90ºC for 12 hours showed a reduction in antimicrobial properties as the temperature increased, even though their antioxidant potential actually improved due to other chemical changes. This confirms that heat-sensitive antimicrobial agents are being compromised. For Manuka honey, while its MGO is more heat-stable, exposure to high temperatures (above 140-158°F or 60-70°C) for prolonged periods will still cause a significant reduction in its overall potency.

Raw vs. Pasteurized Honey: A Comparison


Feature	Raw Honey (Unpasteurized)	Pasteurized Honey (Regular)
Processing	Filtered to remove large debris like wax and pollen. Not heated beyond hive temperature (approx. 95°F/35°C).	Heated to high temperatures (e.g., 160°F or 71°C) to kill yeasts, improve shelf life, and prevent crystallization.
Appearance	Often cloudy or opaque due to containing natural particles.	Clear, smooth, and uniform due to fine filtering and heat treatment.
Health Benefits	Retains all natural enzymes (like glucose oxidase), pollen, propolis, and antioxidants.	Many beneficial compounds, including enzymes, antioxidants, and pollen, are destroyed or significantly reduced by heat.
Antibacterial Activity	Full spectrum activity from multiple mechanisms, including hydrogen peroxide production.	Significantly reduced, primarily losing the hydrogen peroxide-producing enzyme. Manuka honey's non-peroxide activity (MGO) is more resistant but still affected by high heat.
Crystallization	Crystallizes naturally over time due to high glucose content.	Crystallization is delayed, keeping it liquid for longer periods.
Flavor Profile	Retains a more complex and robust flavor, varying by floral source.	Has a milder, more uniform taste as heating can alter delicate flavors.

Practical Recommendations for Preserving Honey's Benefits

If your goal is to utilize honey for its antibacterial properties, keeping it in its raw, unheated form is the best practice. For culinary applications, there are strategic ways to minimize the damage from heat:

Add to warm (not boiling) drinks: If you put honey in tea or coffee, let the beverage cool for a few minutes first. Pouring honey directly into boiling water will immediately destroy its heat-sensitive enzymes.
Use in raw recipes: Incorporate honey into uncooked dishes such as salad dressings, smoothies, or dips to preserve its full range of beneficial compounds.
Drizzle after cooking: For dishes that require cooking, such as glazes or baked goods, add the honey at the end, just before serving. This allows you to enjoy the flavor without sacrificing the antimicrobial benefits.

The Broader Context of Heating Honey

It's important to remember that heating honey does not make it toxic, a persistent myth that lacks scientific evidence. The health risks associated with honey, such as infant botulism, are not altered by standard pasteurization, as the spores that cause it are resistant to the temperatures used.

For most home cooks, the mild heat of a warm beverage will have a less severe impact than the high, prolonged heat of baking. Commercial pasteurization, however, involves sustained high temperatures specifically designed to denature enzymes and prevent crystallization, which also wipes out many of the natural, therapeutic compounds. If you're seeking honey for its medicinal qualities, always opt for raw, unpasteurized varieties and use them without high heat. For high-temperature cooking where the primary purpose is sweetening, using a lower-grade or regular pasteurized honey is a sensible approach.

In conclusion, while honey retains some of its basic antimicrobial power (like high sugar content) when heated, the more sensitive, potent components, such as hydrogen peroxide-producing enzymes and various phytochemicals, are significantly reduced or destroyed. This loss is especially true for pasteurized honey, making raw honey the superior choice for those seeking its full antibacterial benefits. Protecting honey from high temperatures is key to preserving its unique medicinal gifts. Learn more about honey's antibacterial mechanisms from the National Library of Medicine.

Frequently Asked Questions

Most of honey's heat-sensitive antibacterial components, especially enzymes, begin to degrade when heated above hive temperature, which is around 95°F (35°C). Prolonged heating or temperatures above 140°F (60°C) will significantly reduce its potency.

Pasteurized honey has significantly reduced antibacterial properties compared to raw honey. The heating process kills the yeast that causes fermentation but also destroys many of the beneficial enzymes and phytochemicals responsible for its antimicrobial effects.

While Manuka honey's active compound, methylglyoxal (MGO), is more heat-stable than the enzymes in regular honey, prolonged high heat will still cause a significant reduction in its antibacterial properties. To preserve maximum benefits, it is best to use it raw or add it to warm (not hot) foods.

Yes, but with care. Avoid adding honey directly to boiling water. Allow your tea to cool for a few minutes first. The warmth will not completely destroy the benefits, but boiling temperatures will break down heat-sensitive enzymes.

Raw honey is unfiltered and unpasteurized, retaining all its natural enzymes, pollen, and antioxidants. Regular honey is heated and filtered, which removes some beneficial compounds, but results in a clearer, smoother texture and delayed crystallization.

Honey's antibacterial properties are a combination of several factors: high sugar content (osmotic effect), low pH (acidity), the enzymatic production of hydrogen peroxide, and the presence of various phytochemicals and compounds like methylglyoxal (MGO) in Manuka honey.

No, it is a myth that heated honey is toxic. While heat can alter its chemical composition and reduce its health benefits, it does not make it poisonous. However, high heat can cause the formation of a compound called 5-hydroxymethylfurfural (HMF), which has potential side effects when ingested in high quantities over a long period of time.