These can be added by beekeepers, processors or packers. The possibilities include:

• Sugars and other carbohydrates (for example, high-fructose corn syrup, invert-sugar syrup, glucose, molasses, flour and starch).

• Water.

• Environmental contaminants such as pesticides and lead (for example, from vehicle-exhaust fumes).

• Bee and hive medications (such as antibiotics and fungicides).

• Chemicals from plastic (if honey has been heated in plastic pots).

Legal standards for honey quality and tests for adulteration vary from country to country. However, the Codex Alimentarius, compiled by the United Nations Food and Agriculture Organization, requires there to be no adulteration with sugar or water of honey sold to the public.

Batches of honey can be tested for hydroxymethylfurfural (HMF), produced when simple sugars, especially fructose, break down in acidic conditions. A high level may indicate adulteration with sugar syrup, overheating or lengthy storage. Hot climates can raise HMF to over 100mg/kg. Certain countries require a limit of 100mg/kg in imported honey. Bulk-traded honey must usually have an HMF below 10–15mg/kg so as to enable further processing and a longer shelf life before the 40 mg/ kg level is reached.

Invert-sugar syrup (including high-fructose corn syrup)

This contains fructose, glucose and, for high-fructose corn syrup, a little maltose. It's cheap to make, so adding it to honey increases profits. This is most likely in the production of cheap imported blended honeys. Indeed, in certain countries syrup-adulterated, or 'stretched', honey is widely available. Astonishingly, stretched honeys containing up to 80 per cent corn syrup are sometimes labelled 'pure honey'! This dupes consumers into buying what they think is honey, but is actually sugar syrup plus honey.

In 2009, the state of Florida prohibited the addition of adulterants such as sugar syrup to products labelled 'honey'. The US now needs a similar federal law. Strict labelling regulations are required in certain other countries, too.

High-fructose corn syrup (HFCS) is produced by milling corn, processing the resulting corn starch to yield corn syrup, which is almost entirely glucose, then adding enzymes to convert some of this glucose into fructose. The most common, HFCS 55, contains 55g of fructose, 41g of glucose and 4g of maltose per 100g and is 25 per cent sweeter than sugar. Next most common is HFCS 42, with 42g of fructose, 53g of glucose and 5g of maltose and roughly as sweet as sugar.

Another sort of invert-sugar syrup is produced by heating sucrose from sugar cane or beet with acid, or adding invertase, to convert it into glucose and fructose.

Testing for HMF (see page 34) indicates whether a honey is likely to have been adulterated with syrup.

Officials can also test by measuring the activity of the enzyme diastase. This also indicates quality because activity is low if a honey has been:

• Adulterated with syrup (as this dilutes diastase).

• Damaged by overheating (as this destroys diastase).

• Stored a long time (as this gradually reduces diastase).

Some honey adulterers, though, disguise the fall in diastase by adding foreign diastase.

Antibiotics, fungicides and mite-killing medications

Beekeepers use medications to prevent or treat infestation of bees with Varroa mites or to treat bacterial or fungal disease. Various measures can minimize the amounts entering honey.

Interestingly, as mites dislike the scent of certain essential oils, they are less likely to infest a hive if its honey and propolis originate from plants producing these oils. Such plants include coriander and lavender, so it's worth planting these near hives.

Ongoing concern about honey from China dates from certain of their beekeepers using the antibiotic chloramphenicol to treat an epidemic of the bee disease foulbrood that began in 1997. They then exported chloramphenicol-contaminated honey. This antibiotic is toxic to humans, causing a potentially fatal disease called aplastic anaemia in a few of those exposed to even small amounts. Other potentially dangerous antibiotics, including ciprofloxacin, have also been found in Chinese honey.

Regulations were tightened following the scandal over imports of contaminated honey into the EU (European Union) and US. The EU, for example, now requires imported honey to be free from prohibited residues such as certain antibiotics, pesticides and heavy metals.

However, officials suspect very large amounts of honey continue to enter from China into the EU and the US via countries such as India and Vietnam. One reason for this suspected 'honey laundering' is that countries such as India export vastly more honey than they could possibly produce.

In 2008, the US imposed steep anti-dumping trade tariffs on Chinese honey, and its Customs Border Protection stepped up testing of imported honey. The EU has prohibited imports of honey from non-EU countries that are not on the 'Third Country Listing'. Countries on this list must test samples of honey destined for export. In 2010, the EU banned honey from India because there was insufficient clarity about its origin and possible adulteration with invert-sugar syrup or contamination with antibiotics and heavy metals.

Ever-improving measures are vital to prevent fraud.


Bees can make contaminated honey if pesticides have been sprayed on open flowers or systemic pesticides have been applied to a crop. Systemic pesticides spread into nectar. Consuming contaminated nectar can damage bee health. And consuming contaminated honey could, at worst, and if done regularly, damage human health.

Several measures can prevent or reduce pesticide contamination (see page 17).

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