In this brief guide, we will answer the query,” Does honey ever go bad?” and will discuss what factors in honey make it last longer.
Does honey ever go bad?
Yes, honey does go bad. If the beekeeper or the buyer mishandles the honey, it will spoil. The microbes found in honey and honeycomb are bacteria, molds, and yeast; they come from the bees, nectar or from external sources. Pollen, honey bee intestine, human equipment, containers, winds, and dust are possible sources of microbial contamination (1).
Bees remove moisture from nectar by flapping their wings inside of the hive, which results in honey. Bees remove so much water from nectar that it becomes viscous and inherently acidic, which can destroy practically everything that attempts to grow in it. Due to the lack of microorganisms, your jar of honey is guaranteed to last for years to come! However, spore forming microorganisms can survive in honey at low temperature (1).
If you want to keep your honey fresh, this is the most important thing you can do: Keep your honey in the jar. A jar of honey will absorb water from the air, making it easier for germs to thrive. To prevent this from occurring, close your lid to the fullest extent.
There are Several Reasons for Honey’s Long Shelf Life
Because of its high sugar content and low moisture level, as well as its acidic nature and the antimicrobial enzymes generated by bees, honey has a long shelf life. Due to various reasons, most bacteria and other microbes cannot grow or reproduce in honey. Honey has antimicrobial properties that prevent the growth of many microorganisms. In addition, honey has a low water activity, preventing the multiplication and the survival of bacteria. Basically, microbes cannot replicate in honey and the existence of high numbers of vegetative bacteria might be due to recent contamination (1).
Honey has a high sugar content and a low water content.
One of the most effective ways to prevent the formation of germs and mold is to use honey, which contains roughly 80% sugar.
Honey has a high osmotic pressure because of its high sugar content. Microbes’ development and reproduction are halted as a result of water leaking from their cells. Honey’s water activity is also quite low, despite its approximately 17–18% water content.
The higher the water content of the honey the more likely is fermentation and spoilage. The absolute water content is not responsible for the metabolism of the yeast but the amount of free water, described as water activity. The water activity of honey is within a range of 0.5–0.65, which inhibits most of the microorganisms. The water activity needed for development of microorganisms is around 0.70 for mold; 0.80 for yeast and 0.90 for bacteria (2).
Honey can’t ferment or break down because the sugars interact with the water molecules, preventing microbes from using them. Oxygen cannot readily penetrate honey because of its density. This, too, hinders the growth and reproduction of several bacteria. However, osmophilic yeast are specialists which have an obligate need for high sugar concentrations and are able to grow to a minimal water activity until 0.6. Such osmophilic yeast are causing honey fermentation (2).
As a result of its wide pH range and average pH of 3.9, honey is classified as acidic by the International pH Scale (IPHS). nectar’s natural ability to preserve itself is further enhanced by the presence of gluconic acid. The pH of honey ranges between 3.5 and 5.5 depending on its botanical source, the pH of nectar, soil or plant association, and the concentration of different acids and minerals such as calcium, sodium, potassium and other ash constituents. Altered values may indicate fermentation or adulteration (2).
Honey’s acidic atmosphere was formerly assumed to be the cause of its antimicrobial properties. Antimicrobial activity was not found to vary significantly across cultivars with lower and higher pH levels. C. diphtheriae, E. coli, Streptococcus, and Salmonella, on the other hand, are unable to thrive in an acidic environment. Due to the variations of some organic acids and inorganic ions such as phosphate and based on different sources of nectar, honey acidity can result from the action of the enzyme glucose oxidase produced in the hypopharyngeal glands of bees, producing gluconic acid (2).
Indeed, honey is so good at killing specific types of bacteria that it is even applied to burns and ulcers to prevent and cure infections there. As a result of their unique enzymes, bees may inhibit the growth of bacteria. The antimicrobial activity of honey, may be because of the acidity (low pH), osmotic effect, high sugar concentration, presence of bacteriostatic and bactericidal factors, such catalase, antioxidants, lysozyme, polyphenols, phenolic acids and flavonoids, methylglyoxal (formed by conversion of dihydroxyacetone during honey maturation), bee peptides; increase in cytokine release (tumor necrosis factor-alpha) as well as to immune modulating and anti-inflammatory properties of honey. In addition, because honey contains some propolis and bee pollen, part of the antimicrobial activity of honey may be because of the presence of antimicrobial substances present in these components (3).
Bees inject an enzyme called glucose oxidase into the nectar during honey production to help preserve the honey. This enzyme helps to preserve the honey. Sugars in honey are converted into gluconic acid and hydrogen peroxide when the honey ripens. This enzyme remains active even during storage affecting the honey after processing due to the quantity of minerals present, and by bacteria during maturation. Organic acids from honey represent less than 0.5% of solids, but have a considerable effect on taste (2).
Bee honey is considered to contain hydrogen peroxide, (generated by endogenous glucose oxidase), which may contribute to the honey’s antibacterial characteristics and hinder the development of microbes. Additional antimicrobial chemicals discovered in honey include polyphenols, flavonoids, methylglyoxal, and bee peptides, all of which may contribute to honey’s antibacterial properties.
When Is Honey Unusable?
Despite honey’s antibacterial capabilities, it can go bad or cause illness under specific conditions. Some examples include contamination, adulteration, improper storage, and deterioration over time.
Honey may be contaminated
Bacteria, yeast, and molds are some of the germs found naturally in honey. Pollen, the bees’ digestive system, dust, air, soil, and flowers may all be sources of these. Since these organisms are normally found in extremely low quantities and cannot grow, they should not pose a health risk since honey has antibacterial qualities. Even yet, C. botulinum spores have been discovered in as little as 5% to 15% of honey samples in extremely low levels. Besides, honey consumption was associated with 15% of the reported cases of infant botulism to the Centers for Disease Control and Prevention. Up to 25% of the honey products in the US contain spores of Clostridium botulinum (1).
Babies under the age of one are at risk of developing baby botulism, which may lead to paralysis, respiratory failure, and damage to the neurological system. Because of this, honey is not recommended for children under the age of two.
The presence of huge numbers of microorganisms in honey might also suggest secondary contamination during processing by people, equipment, containers, winds, dust, insects, animals, and water.
Plant poisons may be transmitted into honey when bees gather nectar from some kinds of flowers.
Grayanotoxins in nectar from Rhododendron ponticum and Azalea pontica are well-known examples of this. It may induce dizziness, nausea, and difficulties with the heart rhythm or blood pressure if honey is made from these plants. It may lead to cardiac toxicity by augmenting sodium channel permeability and vagus nerve activation (1).
Additionally, during the processing and maturing of honey, a chemical known as hydroxymethylfurfural (HMF) is created. Even while some studies have shown HMF to be harmful in terms of cell and DNA damage, others have found it to be beneficial in terms of antioxidative, allergy, and inflammation qualities. However, final goods should contain no more than 40 mg of HMF per kg of honey.
Hydroxymethylfurfural is an intermediate product of the Maillard reaction, and is formed by the direct dehydration of sugars under acidic conditions, mainly by the decomposition of fructose during heat treatment applied to food. It can be a toxic compound when found in high amounts. In honey, HMF is an indicator of quality which assists in the identification of freshness when in low concentrations. Higher than permitted concentrations may mean that the product has undergone adulteration through the addition of inverted sugar (syrup), has been stored under inappropriate conditions, undergone prolonged storage, been heated, or affected by acidity, water or minerals (2).
Honey may be tainted
To manufacture honey is a costly and time-consuming endeavor. As a result, it has long been a target for fraudsters. Adding inexpensive sweeteners to boost volume and lower prices is known as adulteration.
With the help of sugar syrups made of sugar cane and sugar syrups from maize, honey bees can be fed more cheaply. Honey may sometimes be gathered before it is ripe to speed up processing, resulting in greater and potentially hazardous water content.
Honey is typically stored in the hive and dehydrated to a moisture content of less than 18%. Honey can include as much as 25 percent water if it’s gathered too early. This increases the danger of unpleasant taste and fermentation.
In addition, The formaldehyde content in honey represents, predominantly, amino compounds, allowing the evaluation of peptide content, protein and amino acids. This is an indicator of the presence of nitrogen in honey and is an important adulteration indicator. When low, it can suggest the presence of artificial products, while when excessively high it can show that the bees were fed hydrolyzed protein. Thus, formaldehyde content can be used to prove the authenticity of honey (2).
Storing honey improperly
Honey can lose some of its antibacterial qualities if it is kept improperly. There is a higher danger of fermentation if it is kept open or inadequately sealed since water content might climb beyond 18 percent.
Additionally, unsealed jars and containers might enable bacteria from the surrounding environment to contaminate the honey that is stored within. If the water content becomes too high, they might grow.
Honey’s color and taste may degrade faster and the HMF level can rise as a result of high-temperature heating.
Honey may crystallize and degrade overtime
Even if honey is properly kept, it is not uncommon for it to crystallize. There are more sugars in it than can be dissolved, which is why it’s so sweet. A change in the process does not always signify that the product has gone bad.
The hue of crystallized honey lightens and becomes whiter. It also seems grainy, since it gets considerably more opaque than clear. It’s safe to consume, according to the FDA. However, during the crystallization process, water is released, which raises the danger of fermentation. During crystallization of honey mainly glucose crystallizes by forming glucose monohydrate, fructose is more soluble and stays in solution for longer time. The water fixed to glucose in solution is set free during the crystallization process which means that the water activity increases. Honeys having higher water contents sometimes separate into a crystallized phase at the bottom and a liquid phase on top. This layer containing high water contents increases the risk for spoilage of honey via fermentation (4).
In addition, honey that has been kept for a long period may darken and lose its taste and scent. This isn’t harmful to your health, but it’s not as appetizing or pleasant as other options.
Other FAQs about Honey that you may be interested in.
In this brief guide, we answered the query,” Does honey ever go bad?” and discussed what factors in honey make it last longer.
- Al-Waili, Noori, et al. Antibiotic, pesticide, and microbial contaminants of honey: human health hazards. sci world J, 2012.
- Sereia, Maria et al. Techniques for the Evaluation of Physicochemical Quality and Bioactive Compounds in Honey. Honey Analysis, ed Vagner de Alencar Arnaut de Toledo, IntechOpen, 2017.
- Israili, Zafar H. Antimicrobial properties of honey. Am j therap, 2014, 21, 304-323.
- Gleiter, R. A., H. Horn, and H-D. Isengard. Influence of type and state of crystallisation on the water activity of honey. Food chem, 2006, 96, 441-445.