New manuka honey con

€110-a-jar ‘liquid gold’ may lose its healing powers before you open it

EXPENSIVE manuka honey may have lost its healing powers before customers even get it home, a scientist has warned.

The honey, known as ‘liquid gold’ because it costs up to €110 per jar, is sought after for antibacterial properties that come from a naturally occurring, bug-fighting chemical.

But this chemical can be destroyed by prolonged exposure to heat – such as during shipping or even sitting in shop windows – according to Professor Merilyn Manley-Harris. The honey chemist, of Waikato University, New Zealand, warned some manuka honey may be wrongly labelled as stronger than it really is because it has been damaged by heat.

Popular with celebrities, manuka honey is made from the nectar of the native New Zealand manuka bush. The honey contains the chemical methylglyoxal (MGO), which has antibacterial properties. Jars carry a label detailing the honey’s strength – or how much of this chemical it contains.

But research suggests around half of the honey sold as ‘manuka’ may not be genuine, and some contains less MGO than stated on the label. The honey is tested for strength before it leaves New Zealand, but Professor Manley-Harris said: ‘It’s a minimum of four to six weeks to ship, the containers are not refrigerated and the inside of a hull can get quite hot.’ She added that ‘the way honey is handled in the shop could also affect it’.

This is because heat speeds up the rate at which MGO diminishes. She added: ‘If you’re buying honey that has been shipped, buy one which has also been tested when it arrives. Don’t buy the jar sitting in the window, get one... sitting in the cool.’