Review by the International Honey Commission
Key words: honey, quality, standard, norm, Codex Alimentarius, EU
Stefan Bogdanov (chairman, Switzerland), Cord Lüllmann (vice-chairman, Germany), Peter Martin (secretary, UK), Werner von der Ohe4, Harald Russmann, Günther Vorwohl (Germany); Livia Persano Oddo, Anna-Gloria Sabatini, Gian Luigi Marcazzan, Roberto Piro, (Italy); Christian Flamini, Monique Morlot, Joel Lhéritier, Raymond Borneck (France); Panagyotis Marioleas, Angelica Tsigouri (Greece); Jacob Kerkvliet (Netherlands), Alberto Ortiz (Spain), Tzeko Ivanov (Bulgaria), Bruce DArcy, Brenda Mossel (Australia) and Patricia Vit (Venezuela))1. Bee Department, Federal Dairy Institue, Liebefeld, 3003 Bern, Switzerland, firstname.lastname@example.org, corresponding author
International honey standards are specified in a European Honey Directive and in the Codex Alimentarius Standard for Honey, both of which are presently under revision. In this paper the present knowledge on the different quality criteria is reviewed. The standard drafts, mentioned above include standards and methods for the determination of the following quality factors: moisture, ash, acidity, hydroxymethylfurfural, apparent reducing sugars, apparent sucrose, diastase activity and water-insoluble matter. However, during the last 30 years there are very few published works on reducing sugars and ash content of honey. Instead, specific sugars and electrical conductivity are mostly used. Based on this data, international honey standards for the sum of fructose and glucose content, the sucrose content and electrical conductivity are proposed. Besides, the use of other quality factors, like invertase activity, proline and specific rotation, additionally used in many countries, is also discussed.
Honey quality criteria are specified in a European Directive (1) and in the Codex Alimentarius standard (2), both presently under revision (3,4). The authors of this review are members of the International Honey Commission (IHC), which was formed in 1990 to revise the methods and standards for honey. The commission compiled the methods of analysis currently used in routine honey control and carried out ring trials in collaboration with the honey commission of the Swiss Food Manual (SFM). The methods were first published in the SFM (5) and then in a slightly modified form elsewhere (6). This work of the commission was chaired by Stefan Bogdanov. Presently, the IHC deals with compositional criterea for unifloral honeys under the chairmanship of Werner von der Ohe.
As new, better and faster analytical methods are available nowadays, introduction of new norms, using these new methods is necessary. In recent publication we reviewed extensively the specific sugar content and the electrical conductivity of honey, as well as and the methods, used for the determination of honey quality (7). In this work we focus our discussions on the standard drafts of the Codex Alimentarius and of the EU. In general, the Codex Alimentarius Standard is valid for honey trade in the whole world, while other regional norms, as the European Honey Regulation, can also be established, if there are regional quality requirements, differing from the Codex Alimentrius.
Drafts for Codex Alimentarius and EU honey standards
The last draft for Codex Alimentarius Honey Standard is given in full in the appendix below. If adopted, this standard should be applied by the governments in honey trade all over the world. On the other hand, the specific compositional criteria, given in table one are intended for voluntary acceptance by the honey trade partners.
Are there differences between the Codex and the EU Standards?
The proposed draft for a honey standard in the EU is very similar to the Codex standard, but it contains fewer specific details. Contrary to the EU draft, in the Codex draft there are specific paragraphs, dealing with contamination, hygiene and sugar adulteration, all of these being important quality factors nowadays. On the other hand, there is an important point, contained in the EU standard, but lacking the Codex draft. Thus only the EU proposal contains a definition of "industrial" or "bakery"-honey:
"Honey, which is convenient for human consumption, but which can have unspecific taste or odour, be fermented, was overheated or which has a lower diastase activity or higher hydroxymethylfurfural content than prescribed in the norm".
A paragraph for a honey quality is necessary, as honey for industrial use is often sterilized because of hygienic reasons.
Another important point is the question of honey pollen. The European draft states, that no essential honey components can be removed from honey, while the Codex paragraph 3.2 says, that honey should not be processed to such an extent, as to change its essential composition (see also Appendix). Both statements are ambiguous. There could be different interpretations as to the question, whether honey pollen is an essential honey component. While from nutritional point a view it is of no importance, as honey pollen content is less than 0.01 % of the total, it is important for the determination of the botanical and the geographical origin of honey. Also, honeys is used in some cases for pollen desensitisation, due to its low pollen content. The argument of the honey industry is, that a fine filtration is often necessary for the removal of small foreign particles, impeding honey quality. On the other hand, paragraph 6.1.7. of the Codex says, that honey, subjected to a fine filtration process to improve its clarity should bear a label to inform the consumer about this process. The best solution would be to include a paragraph, stating, that honey should be filtered with filters with a mesh-size, not smaller than 0.2 mm, which will keep the pollen in the honey, but will remove most of the honey impurities. Different European beekeeping federations prescribe the use of such filters for their honey regulations.
The moisture content is the only composition criteria, which as a part of the Honey Standard has to be fulfilled in world honey trade. Honey having a high water content is more likely to ferment. A maximum value of 21 g/100g is suggested in the draft for a new standard. The exception for clover honey is not justified by measurements during recent years. Accordingly, the maximum water content for clover honey should also be 21 g/ 100 g. In practice, values as high as 21 g/100 g are very seldom attained. In routine honey control carried out by the IHA during the years 1989-97 on ca. 30,000 honey samples 91-95 % of all honeys had a water content of less than 20 g/100g (8) Also in Switzerland a standard of 20 g/100 g was successfully used in the past 20 years, until the last revision of the Swiss Food Ordinance, where the European Union maximum value of 21 g/100 g had to be accepted. Many national beekeeping organisations (e.g. Germany, Belgium, Austria, Italy, Switzerland, Spain or others ?) have moisture content maximum values of 17.5 to 18.5 g/100 g for special classes of quality honey.
Specific quality criteria
Table 1 summarises the composition criteria of the EU and the Codex drafts. According to Codex Alimentarius these quality standards are not compulsory for governments and can be voluntarily agreed upon, while according to the EU draft they have to be fulfilled by all commercial retail honeys. As it can be seen, there are only minor differences in both drafts and they both do not contain such important quality criteria as the specific sugar content and electrical conductivity (see Proposal for a New Honey Standard).
Apparent sugar content
In most blossom honeys apparent reducing sugars" represent the great majority of honey sugars, but in honeydew honeys, the situation is often very different. Indeed, many honeydew honeys have high amounts of non-reducing oligosaccharides such as melezitose, maltotriose and raffinose. Because of these findings, the standard for apparent sugars has been modified in the Codex draft, compared with the previous standard: a minimum of 45 g/100 g has been proposed, compared to the old standard with a minimum of 60 g/100 g. The European draft keeps the old norm of 60 g/100g. "Apparent sucrose" is measured indirectly as the difference between total and reducing sugars and can often be different from true sucrose. Here both drafts are similar, the Codex draft including more honey types than the European one. The IHC proposes, that an exception for the apparent sucrose content of rosemary honey be made. Indeed, measurements of 33 Spanish rosemary honeys showed, that a significant portion of these honeys had more than 5 % apparent sucrose.
The measurement of reducing sugars detects only the difference between blossom and honeydew honeys, but this difference can be determined much easier by other methods, e.g. by electrical conductivity determination. There are many arguments for replacing the measurement of the reducing sugars with that of specific sugars (see next section).
Water insoluble solids content
The measurement of insoluble matter is an important means to detect honey impurities that are higher than the permitted maxima. It was set in the times, when a significant portion of world honey was harvested by pressing the combs. However, nowadays almost all commercial honey is harvested by centrifugation. It seems to us that the permitted maximum in the Codex and European standards of 0.1 g/100 g is too high. Mostly lower values, in the range of 0.005 to 0.05 g/ 100 g are found. Wax, which is not determined by the Codex method, is a major source of water-insoluble contamination. For this purpose other filtration technique can be used, e.g. with paper filter, but such a method has not been officially proposed yet.
Mineral content (ash)
The ash content is a quality criterion for honey botanical origin, the blossom honeys having a lower ash content than honeydew honeys (9). At present, this measurement is generally replaced by the measurement of electrical conductivity. The ash content could be kept as a quality factor during a transition period, until conductivity is accepted as a world-wide standard.
Acidity is an important quality criteria. Honey fermentation causes an increase of acidity and because of this a maximum acidity value has proven useful, although there is a considerable natural variation. The old standard fixed a maximum of 40 milliequivalents/kg, which has been increased to 50 milliequivalents/kg in the Codex draft, as there are some honeys, which have a higher natural acidity (10).
Honey diastase activity is a quality factor, influenced by honey storage and heating and thus an indicator of honey freshness and overheating. Although there is a large natural variation of diastase, the present standard of a minimum DN value of 8 has proven to be useful. In long-term routine honey control at the IHA more than 92 % of the raw honey samples (n = ca. 20,000) and more than 88 % of the retail honey samples (n = ca. 1000) had a DN greater than 8 (8). When interpreting diastase results one should take into consideration that certain unifloral honeys have a naturally low diastatic activity. Although the minimal requirements for diastase activity in the Codex and the EU drafts are the same, in practice there is an important difference between the two: while the Codex norm refers to honey after processing and blending, the EU norm is valid for the whole retail honey. In reality this means that the EU norm is more severe than the Codex norm, as diastase activity is expected to diminish upon storage.
This major honey quality factor is an indicator of honey freshness and overheating. In fresh honeys there is practically no hydroxymethylfurfural (HMF), but it increases upon storage, depending on the pH of honey and on the storage temperature. Some European bee federations (Germany, Belgium, Italy, Austria, Spain) market a part of their honey as "quality honey", having a maximum of 15 mg/kg. In international trade, a maximum value of 40 mg/kg has proven satisfactory. In long term routine honey control at the IHA during the last 10 years, more than 90 % of the raw honey samples (n = 30,000) and more than 85 % of the retail honey samples (n = 2000) had less than 30 mg HMF/kg (8). The Codex proposal is a maximum of 60 mg/kg. The proposal for a higher maximum value is based on the experience that HMF increases on honey storage in warm climate countries. The latest EU standard proposal demands a maximum of 40 mg/kg, as under European conditions this standard has proven to be valid. Here too, as in the case with diastase, there is an important difference between the two norms: while the Codex norm refers to honey after processing and blending, the EU norm is valid for the whole retail honey. In reality this means that the EU norm is much more severe than the Codex norm, as HMF is expected to increase upon storage.
Proposal for a new international standard
Conductivity is a good criterion of the botanical origin of honey and today it is determined in routine honey control instead of the ash content. This measurement depends on the ash and acid content of honey; the higher their content , the higher the resulting conductivity (9). There is a linear relationship between the ash content and the electrical conductivity (11):
C = 0.14 + 1.74 A
where C is the electrical conductivity in milli Siemens cm-1 and A the ash content in g/100 g.
Extensive conductivity data on thousands of commercial honeys has been recently published (7). Based on this data we propose that blossom honeys, mixtures of blossom and honeydew honeys should have less than 0.8 mS/cm and honeydew and chestnut honeys should have more than 0.8 mS/cm (see table 2). Exceptions are Arbutus, Banksia, Erica, Leptospermum, Melaleuca, Eucalyptus and Tilia honeys as well as their blends, having an extremely high variation in their conductivity (7).
The conductivity measurement is easy and fast and needs only inexpensive instrumentation. It is very widely used for discrimination between honeydew and blossom honeys and also for the characterisation of unifloral honeys. Thus an introduction of an international conductivity standard is recommended as urgent.
Specific sugar content
Based on the extensive data, that we published recently (7) , a general standard for a minimum content of the sum of fructose and glucose of 60 g/100 g for all blossom honeys and 45 g/100 g for all honeydew honeys can be proposed (table 5). This standard could be fulfilled in more than 99 % of the analysed honeys. For sucrose the situation is more complex. Here the general standard of 5 g/100 g could be fulfilled in more than 99 % of the analysed honeys, with the exception of some unifloral honeys like Banskia, Citrus, Hedysarum, ;Medicago and Robinia honeys with up to 10 g/100 g and Lavandula honeys with up to 15 g/100 g sucrose. The sum of the fructose and glucose content is very close to the sum of all reducing sugars, as fructose and glucose represent mostly more than 90 % of all reducing sugars. Indeed, the proposed minimum standard for the sum of glucose and fructose of 45 and 60 g/100 g for honeydew and blossom honeys is almost identical to the proposed standards for apparent reducing sugars of 45 and 65 g/100 g respectively. On the other hand, the proposed standard for true sucrose is very similar to the one for apparent sucrose (table 2). Exceptions are differences for honeydew honeys, where the "apparent sucrose standard" is 15 g/100 g, while the specific sucrose standards is only 5 g/100 g and for some Australian and New Zealand honeys, which figure in the standard for reducing sugars (table 2), but not in the proposed standard for specific sugars (table 5) as no specific sugar data is available for these honeys.
The introduction of a standard for specific sugar contents will have other positive consequences for routine honey control. Thus, the fructose/glucose ratio and the sucrose concentrations are good criteria for differentiating between different unifloral honeys. Also, the content of different higher sugars as melezitose, maltotriose are good indicator of the honeydew content of honey. The specific sugar spectrum yields also information on honey authenticity and sugar adulteration.
Additional quality factors outside the standards
There are some useful quality criteria, used for the determination of honey quality outside the international honey regulations.
Invertase activity is particularly sensitive to heat and storage damage and is used as a freshness indicator. It was proposed that fresh and unheated honeys should have an invertase number (IN) more than 10; for honeys with low enzymatic activity a IN of more than 4 is recommended (12). Although, like honey diastase, the activity of invertase has a great natural variation (13) its use has been proven in honey quality control. A freshness invertase standard is also used in the honey standards of the beekeepers associations of Germany, Belgium and Spain.
The honey proline content is a criterion of honey ripeness and in some cases, also of sugar adulteration (14). A minimum value for genuine honey of 180 mg/kg is accepted in honey control laboratories. However, it should be taken into account that there is considerable proline variation, depending on the honey type (15).
The overall value for the optical rotation is a resultant of the values of the different honey sugars. The measurement of specific rotation is currently used in Greece; Italy and UK to distinguish between blossom and honeydew honeys. In Italy it was found that blossom honeys (16,17) have negative values of optical rotation, while honeydew honeys have a positive one (16). Whether this method is capable of differentiating these honeys in other geographic regions remains to be examined in future studies.
The present review summarises the present state of knowledge on the quality factors, which should be used in the international honey regulations for the determination of honey quality. As these quality factors are valid all over the world, it is not possible that they satisfy the quality standards of all countries. Some criteria, which are valid only in separate countries can be specified. Also, some European beekeepers associations specify more severe quality criteria for the honey sold under their label than the ones valid for general retail honey. For instance, maximum values of 17.5 -18.5 % for humidity and 15 mg/kg for hydroxymethylfufural content and a minimum value of 10 invertase number units are specified.
Apart from the composition criteria, discussed in this review, specialised honey laboratories use also a number of other quality criteria to determine the botanical and geographical origin of honey, especially the characterisation of unifloral honeys. In its further work the IHC is going to compile and harmonise the methods and criteria, used for this purpose. Indeed, up to now chemical quality criteria for unifloral honeys are valid only in separate countries, but they are not officially recognised in the international honey trade.
Dr. Stefan Bogdanov, Bee Department, Federal Dairy Research Institute, 3003 Bern, Switzerland
Codex Alimentarius: DRAFT REVISED STANDARD FOR HONEY
at Step 6 of the Codex Procedure
1.1 This Standard applies to all honeys produced by honey bees and covers all styles of honey presentations which are processed and ultimately intended for direct consumption. It does not cover industrial honey or honey used as an ingredient in other foods.
1.2 The Standard also covers honey which is packed/or sale in bulk containers, which intended for repacking into retail packs.
Honey is the natural sweet substance produced by honey bees from nectar of plants or from secretions of living parts of plants or excretions of plant sucking insects on the living pans of plants, which honey bees collect, transform by combining with specific substances of their own, deposit, dehydrate, store and leave in the honey comb to ripen and mature.
2.1.1 Blossom Honev or Nectar Honev is the honey which comes from nectars of plants.
2.1.2 Honevdew Honev is the honey which comes mainly from excretions of plant sucking insects (Hemiptera) on the living parts of plants or secretions of living parts of plants.
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. The colour of honey varies from nearly colourless to dark brown. The consistency can be fluid, viscous or , partly to entirely crystallised. The flavour and aroma vary, but are derived from the plant origin.
3. ESSENTIAL COMPOSITION AND QUALITY FACTORS
3.1 Honey sold as such shall not have added to it any food ingredient, including food additives, or other substance foreign to honey. Honey shall not have any objectionable matter, flavour, aroma, or taint absorbed from foreign matter during its processing and storage. The honey shall not have begun to ferment or effervesce.
3.2 Honey shall not be heated or processed to such an extent that its essential composition is changed and/or its quality is impaired.
3.3 Chemical or biochemical treatments shall not be used to influence honey crystallisation.
3.4 Moisture Content
(a) Honeys not listed below - not more than 21%
(b) Heather honey (Calluna) - not more than 23%
(c) Clover honey (Trifolium) - not more than 23%
The following provisions in respect of contaminants, other than pesticide residues are subject to endorsement by the Codex Committee on Food Additives and Contaminants.
4.1 Heavy Metals
Honey shall be free from heavy metals in amounts which may represent a hazard to human health.
4.2 Pesticide Residues
The products covered by this standard shall comply with those maximum residue limits for honey established by the Codex Alimentarius Commission.
The following provisions in respect of food hygiene of this product are subject to endorsement by the Codex Committee on Food Hygiene.
5.1 It is recommended that the products covered by the provisions of this standard be prepared and handled in accordance with the appropriate sections of the Recommended International Code of Practice - General Principles of Food Hygiene recommended by the Codex Alimentarius Commission (CAC/RCP 1-1969, Rev 3-1997), and other Codes of Practice recommended by the Codex Alimentarius Commission which are relevant to these products.
5.2 To the extent possible in good manufacturing practice, the honey when sold as such to the final consumer shall be free from objectionable organic and inorganic matter such as insects, insect debris, brood or grains of sand.
5.3 When tested by appropriate methods of sampling and examination, the product:
(a) shall be free from microorganisms in amounts which may represent a hazard to health;
(b) shall be free from parasites which may represent a hazard to health; and
(c) shall not contain any substance originating from microorganisms and plants in amounts which may represent a hazard to health.
In addition to the provisions of the General Standard for the Labelling of Pre-packaged Foods (CODEX STAN 1-1985), the following specific provisions apply:
6.1 The Name of the Food
6.1.1 Products conforming to the standard shall be designated 'honey'.
6.1.2 For products described in 2.1.1 the name of the food may be supplemented by the term "blossom " or "nectar".
6.1.3 Products described in 2.1.2 the name of the food shall be in close proximity to the word "honeydew".
6.1.4 Honey may be designated by the name of the geographical or topographical region if the honey was produced exclusively within the area referred to in the designation.
6.1.5 Honey may be designated according to floral or plant source if it comes wholly or mainly from that particular source and has the organoleptic, physicochemical and microscopic properties corresponding with that origin.
6.1.6 Where honey has been designated according to floral or plant source (6.1.5) then the common name or the botanical name of the floral source shall be in close proximity to the word "honey".
6.7.7 Honey which has been subjected to a fine filtration process to improve its clarity- shall bear a description to inform the consumer of this process. _The subsidiary designations listed in 6.1.8 may not be used unless the honey conforms to the appropriate description contained therein. The styles in 6.1.9 (b) and (c) shall be declared.
6.1.8 Honey may be designated according to the method of removal from the comb.
(a) Extracted Honev is honey only obtained by centrifuging decapped broodless combs with or without the application of moderate heat.
(b) Pressed Honey is honey obtained by pressing broodless combs with or without the application of moderate heat.
(c) Drained Honev is honey obtained by draining decapped broodless combs with or without the application of moderate heat.
6.1.9 Honey may be designated according to the following styles:
(a) Honev which is honey in liquid or crystalline state or a mixture of the two;
(b) Comb Honev which is honey stored by bees in the cells of freshly built broodless combs and which is sold in sealed whole combs or sections of such combs;
(c) Honev with comb which is honey containing one or more pieces of comb honey;
6.2 Labelling of Non-Retail Containers
6.2.1 Information on labelling as specified in The General Standard for the Labelling of Pre-packaged Foods and in Section 6.1 shall be given either on the container or in accompanying documents, except that the name of the product, lot identification and the name and address of the manufacturer or packer shall appear on the container.
Table 1 Honey Quality Standard according to the draft CL 1998/12-S of the Codex Alimentarius and to the Darft 96/0114 (CNS) of the EU
* - the European draft refers to honeydew honey and mixtures of honeydew and blossom honey, acacia, Banksia and Citrus honeys
** - The IHC proposes also that Rosemarinus be included in this list (see text)
Industrial or bake-honey
|Apparent Reducing Sugars Content
Honeys not listed below
honeydew honey or blends of honeydew honey and blossom honey
³65 g /100 g
³45 g /100 g
³53 g /100 g
³65 g /100 g
³60 g /100 g
³53 g /100 g
|Apparent Sucrose content
Honeys not listed below
Robinia , Lavandula, Hedysarum, Trifolium, Citrus, Medicago,
Eucalyptus cam., Eucryphia luc. Banksia menz.* Rosemarinus**
Calothamnus san., Eucalyptus scab., Banksia gr., Xanthorrhoea pr., honeydew honey and blends of blossom with honeydew honey
£5 g/100 g
£10 g/100 g
£15 g/100 g
£5 g/100 g
£10 g/100 g
|Water-Insoluble Solids Content
£0.1 g/100 g
£0.5 g/100 g
£0.1 g/100 g
£0.5 g/100 g
|Mineral Content (ash)
honeydew or blends of honeydew and blossom honey or chestnut honey
£0.6 g/100 g
£1.2 g/100 g
£0.6 g/100 g
£1.2 g/100 g
|Diastase Activity (diastase number
in Schade scale)
after processing and blending (Codex)
general for all retail honey (EU)
honeys with natural low enzyme content
after processing and/or blending (Codex)
for all retail honey (EU)
Table 2. Sugar content and electrical conductivity: proposal for a new honey standard
Suggested New Quality Criteria proposed Value
Sum of fructose and glucose
honeydew honey or blends of honeydew honey and blossom honey
honeys not listed below
Banksia, Citrus, Hedysarum, Medicago, Robinia. Rosemarinus
³60 g / 100 g
³ 45 g / 100 g
£5 g/ 100 g
£10 g/ 100 g
£ 15 g/ 100 g
Blossom honeys excepted the honeys listed below and blends with them; blends of honeydew and blossom honey
Honeydew and chestnut honey, excepted the honeys listed below and blends with those
Exceptions: Arbutus, Banksia, Erica, Eucalyptus, Eucryphia, Leptospermum, Melaleuca, Tilia.
Last update: 10/08/01
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