Like many foodborne illnesses, toxic honey poisoning can be a killer.
Symptoms include vomiting, delirium, giddiness, increased excitability, stupor, coma, and violent convulsions. And it can be a quick tipping point from illness to death.
As little as a teaspoon can have a severe effect on the human nervous system.
Bees feeding on tutu bushes native to New Zealand produce the honey,
which is toxic because of tutin, a naturally-occurring toxin produced by the bush. It makes New Zealand honey risky.
So what level is safe?
The current temporary maximum limits for tutin in honey (2 milligrams per kilogram) and comb honey (0.1 mg/kg) are due to expire on March 31, 2011, but Food Standards Australia New Zealand (FSANZ) wants to retain those same limits for another two years.
It has released the documents for the extension and invites public comment until Nov. 9, 2010.
If extended, the limits for toxin tutin in honey and comb honey would continue to March 31, 2013.
The current limits appear in the Australia New Zealand Food Standards Code and must be complied with by the food industry in Australia and New Zealand.
Tutu is a widely distributed native species found throughout New Zealand, particularly along stream banks and in regenerating native bush.
Although the poison comes from the native tutu bush, toxic honey is not produced by bees gathering nectar or pollen from tutu flowers, but rather when bees gather honeydew produced by the sap-sucking vine hopper insect that feeds on tutu plants.
The honeydew (a sweet exudate) produced from the tutu plant contains tutin, a member of the picrotoxin group. The toxin has no effect on bees and honeydew honey is chemically very similar to floral honey. It cannot be distinguished by taste, sight or smell from other non-toxic honeys.
No heating or other processing step will degrade the toxin.
The toxins are believed to be very stable, and people who ate honey that was several years old have been poisonined.
Both comb honey and extracted honey can be poisonous, but the comb honey poses a greater risk because if eaten directly off the comb the chance of consuming honey with a high concentration of tutin is increased.
Extracted honey is often bulked or blended with other honey, thereby reducing the concentration of toxin.
While tutin and its derivative, hyenanchin, are extremely toxic to humans, only a few areas in New Zealand regularly produce toxic honey.
These areas include the Coromandel Peninsula and Eastern Bay of Plenty (EBOP) and the Marlborough Sounds. To produce toxic honey, all of the following conditions are required:
- concentrations of numerous tutu bushes
- high numbers of vine hoppers
- hot dry weather that allows the honeydew to build up on the tutu plant (rain can wash it off)
- an absence of more attractive food sources for bees, usually caused by drought
- presence of honey bees being managed for honey production
The last outbreak of toxic honey poisoning involving commercial sales occurred in 1974 and involved 13 patients. There have been nine other cases since.
Beekeepers are required to manage the risk that their honey contains tutin by either:
- removing hives and supers containing honey for human consumption before the risk period, or
- by closely monitoring the tutu, vine hopper and foraging conditions in the areas (a 3 km radius) around the apiary while honey is being produced.
Public comments are now being accepted. Details of the Assessment Report for Proposal P1009 can be found at www.foodstandards.govt.nz.
