By Elena Zioga
Honey is a complex natural product produced by many social insects such as bees (Apinae, Meliponinae, and Bombinae), honey wasps (Polistinae), and honey ants (Formicinae and Dolichoderinae). However, the most important source of honey sold commercially comes from only few of the 20,000 bee species – the honey bees (Apis spp.).
Honey benefits for humans
Honey has been exploited by humans since ancient times, and nowadays is a widely consumed product, appreciated for its taste and its health benefits. It contains a variety of ingredients, such as sugars, amino acids, minerals, enzymes and vitamins, which are beneficial to humans. The main sugars of honey (fructose and glucose) are digested more easily and quickly by the human body compared to other sugar types. In addition, glucose is the only form of sugar that can be used by muscles, so honey is an excellent source of energy for children and athletes. The minerals (potassium, calcium, copper, iron, magnesium, manganese, phosphorus, sodium, zinc and selenium) in honey help the body’s cells function, maintain healthy bones and teeth and prevent blood clotting. The main naturally occurring enzymes in honey (diastase, invertase, and glucose oxidase) enhance the digestion of food substances, especially carbohydrates such as sugars and starch. Also, honey contains many vitamins, such as ascorbic acid (C), thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), and pyridoxine (B6), etc., which contribute to the absorption of sugars by the body and to its proper functioning.
What is honey?
As a natural product, honey, even when it comes from a single hive, varies in terms its physicochemical characteristics. A recent study on Irish honeys demonstrated that the physiochemical properties varied according to floral origin, and whether hives were placed in urban or rural sites. The botanical origin and ripening conditions of honey are the main factors responsible for this variance, affecting its natural properties (e.g. colour, aroma, taste, tendency to granulate or ferment, density, viscosity and fluidity, hygroscopicity), but also its antioxidant and antibacterial action. Thus, by studying all the physicochemical, organoleptic and microscopic characteristics that define a specific honey category, we can assign an identity to honey and evaluate it qualitatively in accordance with the international legislation. It is important for the consumer to know how the quality of honey is determined, and to maintain a good value for money, given the widespread practice of adulteration in imported honeys.
According to the broader definition given by Codex Alimentarius (2001), honey is defined as “the natural sweet substance produced by honey bees from the nectar of plants or from secretions of living parts of plants or excretions of plant sucking insects on the living parts of plants, which the bees collect, transform by combining with specific substances of their own, deposit, dehydrate, store and leave in the honey comb to ripen and mature“. On a European level, the Council Directive (2001/110/EC), defines honey as “the natural sweet substance produced by Apis mellifera bees (“bees”). Honey consists essentially of different sugars, predominantly fructose and glucose, as well as other substances such as organic acids, enzymes and solid particles derived from honey collection“.
Based on those definitions, honey can be divided into two main categories:
- Blossom or Nectar honey, produced from the nectar of either one kind of flowers – uni-floral (e.g. oilseed rape, brambles, orange, cotton, sunflower, heather etc), or of the combinations of various kinds of flowers – multi-floral.
- Honeydew honey, produced from secretions of living parts of plants or plant sucking insects on the living parts of plants (e.g. honey of pine, fir, oak and other forest plants).
A notable difference occurs between the two honey definitions. While Codex Alimentarius (2001) mentions that honey is produced by “honey bees“, which is more generic term, the European Directive mentions specifically the species “Apis mellifera L.”. This is because A. mellifera is the honey bee species that occurs and is domesticated for honey production in European Union (EU), while other honey bee species may occur and are being exploited for honey production in other parts of the world (e.g. A. cerana in South Asia).
Honey production by the species A. mellifera
A worker honey bee, after emerging from its cell as a mature adult, lives for almost six weeks in the summer, spending the first three weeks of its life inside the hive as a “domestic honey bee”. After this period, she becomes a collector and works the second half of her life outside the hive collecting nectar, pollen and water (Fig. 1). Honey production is the most important work of honey bee collectors. They fly diligently and tirelessly from morning to dusk in all directions and at various heights and distances up to 10 km from the hive in search of plants that produce nectar. When the nectar source is found, the honey bee sucks the nectar from the flower with her proboscis and temporarily stores it in a special receptacle inside her body, called the honey stomach, foregut or crop. To gather a full crop load of nectar, a bee forager may visit up to 1,000 flowers, and may make around 10 trips per day. When the honey stomach is full, the forager honey bee returns to the hive. Upon her return, she adds the enzyme invertase to the collected nectar. This action initiates the process of turning nectar into honey. The enzyme breaks down the sucrose found in nectar into simpler and more digestible sugars for honey bees, which are mainly glucose and fructose. Back in the hive, the honey is delivered to the nurse honey bees, who store it in the honeycomb cells. Once it enters the cells, the water must be evaporated, for the dehydration process to begin. In order to do that, nurse honey bees flutter their wings, dissipating the extra moisture and turning it into honey. Once this process is completed, the nurse honey bees will cover the top of each filled cell with a thin layer of wax and close it airtight for future use.
Figure 1. A forager honey bee (A. mellifera) collecting pollen and nectar from a Cistus sp. plant.
Honey fraud
According to Food and Agriculture Organization of the United Nations (FAO), despite the overall increasing trends in the number of managed western honey bee hives, important seasonal colony losses are known to occur in some European countries and in North America, while data for other regions of the world are largely lacking. On the other hand, honey demand has increased worldwide, due to recognition of its natural medicinal and nutritional properties and its wide range of applications in food industry.
Hence, honey is becoming an increasingly scarce commodity and, as a natural product with a relatively high price, honey is among the top 10 foods with the highest adulteration rate in the European Union. Consumers, often unknowingly, do not receive the natural product they paid for, while adulterated honey found in the market may pose a threat to food safety, food security, and ecological sustainability. A conscious consumer should be aware of the problem of honey fraud and how to get suspicious of it.
The general term “food fraud” can be taken as encompassing a wide variety of activities referred to adopting the wording contained in European Regulation (2017/625) as “fraudulent or deceptive practices” by businesses or individuals for the purpose of gaining some form of undue advantage and/or causing harm. The EU Commission has also developed a criterion for identifying instances of food fraud that accounts for features such as identifiable violations of EU rules (as set out in Article 1(2) of Regulation (EU) 2017/625), deception, economic gain and intention. Directive 2001/110/EC limits human intervention that could alter the composition of honey and thereby allows for the preservation of the natural character of honey. It prohibits the addition of any food ingredient to honey, including food additives, and any other addition other than honey. Similarly, that Directive prohibits the removal of any constituent particular to honey, including pollen, unless such removal is unavoidable in the removal of foreign matter. Those requirements are in line with the Codex Alimentarius standard for honey (2001). Νon-compliance with the above mentioned guidelines constitutes honey an adulterated product.
Types of honey fraud
- Indirect honey adulteration pre-harvest
Anything that suggests improper feeding of honey bees with sugar during honey production or addition of sugars to honey falls into this category (Fig. 2). The sweeteners that can be used for this purpose are invert sugar syrups, high fructose corn syrups, syrups of natural origin such as maple, cane, sugar beet, molasses, etc. At present, these sweeteners are mainly feed syrups, produced by the hydrolysis of corn starch, cane sugar or sugar beet. Good beekeeping practice ensures that sweeteners used to feed the honey bees in the context of the stimulant feeding during the main nectar flow period should not be made to such an extent as to distort the honey. Nevertheless, the additional feeding in order to increase the yields in honey production is a serious form of fraud. Even untimely stimulant feeding may cause adulteration to the final product. This happens because sucrose syrup or isoglucose and other commercial feeds when administered to honey bees during the time they collect nectar and store it, are incorporated into honey and degrade its quality, distorting the final product. In general, the over-feeding of honey bees with syrup during the flowering period is a form of honey adulteration which is easily detected by the chemical characteristics of the product. In their attempt to increase the amount of honey produced, beekeepers sometimes feed the honey bees with sugar syrup in a ratio of 1:1. When this quantity exceeds the established standard limits, the quality characteristics of the honey are altered and if a relevant control is carried out – based on the quality criteria for a certain honey type, then the beekeeper will have to face serious penalties. Thus, feeding of this kind should be stopped at least one month before the forthcoming flowering period. Intense feeding during the summer months in order to fill the “gap of flowering”, may also affect the quality of the honey collected in the first harvest of autumn.
Figure 2. Supplementary feeding of honey bees with sugar solution during a research experiment.
2. Direct honey adulteration post-harvest
There are two cases in this category both aiming for higher commercial profits for honey producers. The first case concerns the possibility of blending the produced honey with various cheap sweeteners (like the ones already mentioned above), under the use of heating in order to achieve homogenization of the final product. Then, this blended mixture is resold as “genuine” honey. At a European level, almost a year ago, a supermarket chain withdrew pots of its own-brand honey amid concerns that it contains adulterated ingredients. In the second case, the honey production industry, uses glucose, caramel color or simply adds honey aroma to syrup through chemical treatments in order to produce a sweet substance resembling to honey. Another form of post-harvest adulteration is when honey is filtered or pasteurized in order to extend the shelf life. During this process, pollen is removed and along with it, all the benefits of its consumption.
3. Different botanical or geographical origin from that written on the label
Since honey bees visit various plant species, the honey produced is a mixture of different plant sources. Usually, honey is classified as being unifloral when at least 45% of pollen grains arise from a single species (with few exceptions). Consumer’s choice is linked to unique organoleptic and aromatic properties of honey that depend principally on the botanical and geographical origins of the product. Hence, the geographical categorization of honeys can raise its commercial value and contribute to the micro economy of the region. When certain types of honey (due to the varying preferences of consumers) are sold under higher prices in the market, honey producers may often provide the wrong botanical source of honey in order to mislead the consumer.
According to the European Directive 2001/110/EC, if honey originates from more than one member state or a country outside the European Union, this should be indicated in the product label as “blend of EU honey”, “blend of non-EU honey” (Fig. 3), or “blend of EU and non-EU honey” (Fig. 3). This provision is not valid in Codex (2001) leaving room for fraudulent listed information on the label. As for the so-called “local honey” it may not always be “local honey”, but cheap or low-quality honey imported from other countries, and then packaged and distributed locally (Fig. 4). Generally, legal standards and specifications for food, including the quality of honey, as well as tests for controlling honey adulteration vary widely between countries and continents.
Figure 3. Honeys with the indications “Blend of Non EU honeys” and “Blend of EU and Non EU honeys” on their labels.
Figure 4. The indication on this label is “Non-blended EU honey”. This closely resembles the indications that should be provided according to the guidelines of the European Directive 2001/110/EC, however, it does not clearly indicate the European country of origin.
4. Misbranding
Honey that contains misleading information on the label. In 2011, a multinational investigation on honey market fraud, uncovered the largest food industry fraud – Fifteen people across multiple countries were indicted for illegally diverting more than $80 million worth of honey from China to the United States. The practice of re-labelling the product with the intent to hide the country of origin is a considerable problem in the case of honey imported into the US, and is referred to as “honey laundering“. Another example is a honey that may deceitfully be labelled as “organic” notwithstanding the presence of antibiotics, pesticide, heavy metals or pesticide residues in the final product. Given the widespread use of chemical products in crops, it is difficult to guarantee that the honey produced by honey bees is “pure” (Fig. 5). When choosing honey in a store, it is almost impossible to distinguish pure from adulterated honey by simply looking at the contents in the jar or from the label. Unfortunately, a label with the indication “pure honey” on it, does not guarantee the content. Names such as “fresh” or “raw” honey may indicate that the honey in question is freshly harvested and has not been heat treated. Also, many honey production companies add high fructose corn syrup to their honey, which is made from genetically modified corn, and this may never be recorded on the label of the final product. According to the Irish Department of Agriculture, Food and the Marine, honey offered for sale to the consumer must comply with the European Communities (Marketing of Honey) Regulations 2003 (SI No. 367 of 2003). These regulations aim to ensure the honey is of acceptable quality and accurately labelled, especially in terms of origin.
Figure 5. Honeys with the indication “pure” on their labels.
General malpractices reducing honey quality
In addition to the various counterfeits that honey can suffer, there are other manipulations that beekeepers must pay special attention to, in order to avoid degrading the quality of the product produced; for example, the unorthodox use of chemical interventions in the hive and in the warehouse for the treatment of honey bee pathogens and diseases (e.g. to protect against varroa mites and nosemiasis). All the chemical treatments used in the hive encumber both honey and other honey bee products with residues that degrade the quality of the final product. The season and frequency of application, its type, the presence of open honey cells in the hive, and the rate of nectar secretion significantly affect the presence and concentration of chemical residues in honey. The EU has established limits for the maximum quantities of residues in EU honey and these limits should not be exceeded. However, many honeys sold in supermarkets are imported from countries outside the EU (e.g. China and India), and it is common for such products to be withdrawn because they contain banned and even carcinogenic antibiotics.
Harvest of unripe honey
Normally the water content of honey harvested in countries with mild climates is less than 18%. However, in some countries the collected honey has more than 20% humidity due to climatic or collecting conditions. Directive 2001/110/EC stipulates that honey bees dehydrate and store honey, leaving it in the honeycomb to mature after having sealed the cells. When the beekeeper harvests before the honey bees have time to “store, dehydrate and let it mature”, the water content can be as high as 25%. Asian beekeepers frequently harvest unripe honey with high water content, reducing the work of non-forager honey bees, who become foragers at an earlier age, thus, increasing the harvesting capacity of the colony and the producer’s yields. This honey is easily fermented before it is even transported to the place of artificial evaporation (honey factory), a practice that is not in accordance with the directions of Codex Alimentarius (2001). Moreover, the resulting product does not have the desired characteristics of an authentic honey.
Overheating of the product
Nowadays most commercial honeys are produced by centrifugation at 25-32˚C, similarly to the temperatures in the honeycomb cells. The use of heating for sterilization and liquefaction can adversely affect the quality of honey, such as the evaporation of volatile compounds and the reduction of enzyme activity. Alteration of the quality characteristics of honey can be performed by submitting it post-harvest to high temperatures, as well as during transport for international trade. When a producer wishes to mix his/her honey with another honey type in order to obtain more desirable characteristics for the consumer and thus facilitate its promotion on the market, he/she may use heating to facilitate the blending process, risking to alter the quality characteristics of the final honey blend.
Generally, it is difficult to be certain of the authenticity of honey without evaluating the samples in a scientific laboratory by performing specialized analyses with scientific methods such as magnetic resonance, Raman spectroscopy, DNA-based, carbon isotopes, electronic nose or electronic tongue etc. Nevertheless, if you try one of the methods discussed above or have a reason to suspect that the honey you bought is adulterated, I suggest staying away from that honey. Adulteration with cheaper sugars reduces the natural high quality of honey and constitutes this product not safe for consumption. According to a recent review study, six sugar based honey adulterants (cane sugar, corn syrup, palm sugar, invert sugar, rice syrup, and inulin syrup) were found to have a negative impact human health. Specifically, they impair the proper function of many body organs (liver, kidney, heart and brain), by increasing human’s blood sugar levels, causing diabetes, abdominal weight gain and obesity, raising blood pressure and lipid levels, and leading to arterial stenosis. However, the exact adverse effects of adulterated honey consumption on human health, are not fully established yet, due to the absence of systematic and scientific studies and lack of public awareness.
Two myths and two truths about honey
Two myths
“My honey granulates, I am pretty sure it is authentic good quality honey”.
In many cases a honey granulates, and from a liquid form it becomes a solid and a bit crunchy sweet mass. Honey is a super-saturated solution of sugars, so it is only a matter of time before it will become granulated. In addition, some honeys from nectar of certain flowers are particularly prone to granulation (e.g. oilseed rape, clover, orange etc.). Buying honey in the honeycomb is (perhaps) a way to be more certain of the quality of the product as consumers can be sure that the honey has not been adulterated with sugar solution post-harvest (Fig. 6). However, this does not eliminate the possibility of an indirect pre-harvest honey fraud. Ultimately, these practices have an impact on the viscosity of honey produced, which resembles the viscosity of syrup – but this is not the rule.
Figure 6. Acacia honey sold along with the honey comb.
“I bought this expensive honey. It must be of good quality“.
Prices are not always a good indication of the quality of honey. In cases of honey fraud, which have occurred in Chinese honey exports in the past, traders had combined different types of cheap and low-quality honey with expensive honey in order to increase the yield. On the other hand, the emergence of large quantities of adulterated honey, is driving prices down through the abundance of cheap, so-called “honeys”. A study conducted by the Canadian Government in 2019 found almost a quarter of commercial honey brands had been adulterated. Illicit products are eroding market prices and consumer trust, while causing significant damage to the beekeeping industry.
Two truths
“Honey with darker color shade is richer in nutrients”.
Honey color depends on the flowering vegetation of the area where honey bees forage for nectar (Fig. 7). The color of honey can also be affected by the management practices of the beekeeper (e.g. how frequently the wax is changed), or by contact with metals and exposure to high temperatures and light. Thus, the color of honey may not be a good indication of its quality. However, darker honeys usually have a stronger flavor and are often richer in antioxidant agents than lighter honeys.
Figure 7. Various honey types and their respective color palette (Image modified from http://tzoumerkabees.blogspot.com/2011/06/blog-post.html).
“Honey does not really have an expiration date“.
Due to the current legislation, companies are obliged to assign an expiration date to the final product. But the truth is that unprocessed honey can be stored for long periods of time. So, once honey becomes granulated, it can be restored it to its previous state using the bain-marie heating method.
To conclude, it is up to you and your personal taste to choose the type of honey you want to consume. However, my advice is to always pay attention to all the information provided on the label (especially when you buy honey from the supermarket or if it is imported honey). I personally prefer consuming honey produced and packed in my local area, from the beekeeper of my town or from the official beekeeping organization in my country of residence.
Speaking about Irish honey, a recent study has shown that Irish heather honey had similar physiochemical characteristics to Manuka honey. So, why import 4,086 tons of honey from the other side of the world? Be a smart consumer, now you know!
About the author:
“Since I was a young child, I grew up close to my grandfather who was a beekeeper himself. Close to him, I inherited his passion and respect for the honey bee community and witnessed the amazing natural process of honey making. Later on, during my undergraduate studies (School of Agriculture, Forestry and Natural Environment), I pursued doing my thesis on a honey bee related subject. It was when I learned about the different ways of honey adulteration and came across food fraud issues for the first time. Ever since, I became very sensitive in terms of what ends up in our table and how we, the consumers, can be more aware of our food choices.
Nowadays, I am also very sensitive in terms of what ends up in bees’ food, and I am still trying to figure that out with my study on ‘Characterizing pesticide residues in floral resources for bees’.“
Elena Zioga is a 3rd year PhD student at Trinity College Dublin, working on the PROTECTS project, under the supervision of Jane Stout and Blanaid White.
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