Avoiding toxic contamination of your honey
Honey seems so natural and wholesome that it’s difficult to imagine it causing harm. But if your honey is contaminated with another natural substance – tutin – it can be toxic to humans, causing nausea, vomiting, convulsions, and even death.
Tutin is found on the native tutu shrub. A tiny insect called the passion vine hopper feeds on the tutu plant and excretes a substance – honeydew – onto the branches and leaves of the plant. When honeybees feed on this honeydew, they contaminate their honey, making it toxic for humans.
Fortunately, there are ways to avoid tutin contamination. Harvesting early, testing high-risk hives, avoiding some honeycomb, and disposing of contaminated honey can all help keep your honey safe.
Tutu plants and passion vine hoppers are the main culprits behind tutin contamination, but other factors can have an effect as well. For example, hot, dry summers increase the risk because they lead to a build-up of honeydew on tutu leaves and branches, which is then ingested by bees.
It’s important to be aware of the risk factors, and to keep a close eye on your hives, particularly if you’re in one of the high-risk areas – like the Coromandel, the Eastern Bay of Plenty, and the Marlborough Sounds.
Learn to identify tutu plants and passion vine hoppers, so you can keep an eye out for both. If you see your bees feeding on tutu plants, you can assume that they’re eating honeydew and raising the risk of tutin contamination – making testing essential.
Harvest times and testing
Because tutu flowers in late summer, harvesting honey early can help mitigate the risk of contamination. The Ministry for Primary Industries requires testing for honey harvested after December 31st, but beekeepers can avoid the risks – and costs – by harvesting before this time. Comb honey, which is unprocessed and therefore has the highest levels of tutin, can only be sold if it is harvested before December 31st.
If you do choose to harvest later in the season, you must test and provide results before you can sell your honey for the year. In fact, even if you simply plan to give away or eat your own honey, testing is essential. The risks are just too high. Not only are beekeepers liable for prosecution if they poison someone with tutin, but the toxin can cause serious harm and even death in extreme cases.
The maximum level of tutin contamination is 0.7mg per kg. If your tutin level is higher, you can choose to dilute the affected harvest with uncontaminated honey to bring the concentration down.
However, if levels are particularly high it may not be worth trying to dilute your crop. Some beekeepers simply dispose of toxic honey, while others choose to feed it back to their hives. If you do decide to do this, be aware that the honey produced in the next season could also be affected.
Smart choices for safe honey
Early harvests and testing help mitigate the risks of tutin contamination, but some risky honey can always slip through the cracks.
If you’re in a high-risk area, avoid eating honeycomb or pure extracted honey between mid-December and March, from your own hives or others. Avoid buying honey from smaller producers who may be unregistered and unaware of the standards. Unfortunately, it’s also smart to be wary of friends and neighbours giving honey away – home beekeepers are even less likely to be aware.
Tutin contamination sounds alarming – and it can be – but because we live in a country with robust food regulations and testing standards, tutin poisonings are not very common. Most contaminated honey is caught before it’s sold, and more and more producers are harvesting early to avoid issues.
Whether you’re a large producer, a hobbyist beekeeper, or simply a consumer of honey, always it’s better to be aware of the risks.