The bees secret to pristine Manuka Honey and how bees conserve their food

Have you ever wondered why honey can last for years, decades or even centuries? How do bees make this sugary substance that nearly lasts forever? At the end of the day honey is mainly sugar. So why then does honey not spoil? Why is it that bacteria cannot grow in this “sweet” environment? Also why do bees even “manufacture” honey?

Not your usual flying insect

This golden tale begins with one of the most fascinating creatures in nature - the honey bee. The honey bee is an insect that has evolved a complex social structure tasked with building large communities that can achieve amazing things. There are solitary bees which don’t have social structures, however, these bees live in small holes they dig for themselves, make no honey, no comb and none of the amazing things the honey bee with their complex social structure build.

How do bee’s store “fat”?

Unsurprisingly, like many other animals on Earth, one of the biggest challenges for a bee is to make it through the cold winter months, when only a few flowers are around. Animals typically store fat in their bodies to ensure they have enough energy stored for winter. However for a small insect like a bee, storing fat is not an option. Bees have evolved a way of outsourcing energy storage, from the body of an individual bee, to the whole colony. In this sense, the honey is the “stored fat” that all bees can use in winter months, just as a bear hibernating through winter relies on the fat accumulated through the summer and autumn months. Honey, therefore, is the energy rich food bank saved for long winter nights.

Defending their community

Unfortunately, banks can get robbed and while fat in the body of an animal can be protected by the animal’s immune system, the honey is stored in the comb and terribly exposed to the elements from the environment. While the bees can defend their food storage against other animals through their painful stings, bacteria and yeast can easily spoil sugar rich foods. Because of the susceptibility of nectar to spoil, bees cannot store the nectar they collect directly in the hive. Bees therefore modify the nectar by incorporating their own in-built defence mechanisms. A product that can withstand the elements and the test of time. That product is honey!

Bees transform nectar through an elaborate procedure in which they reduce its water content, add enzymes to change the composition and mix it all together. The end result is the honey in the comb we know. A well-defended superfood that is protected against microbial spoilage. This defence consists of several layers, as one layer might be broken or circumvented by hungry microbes.

The defence layers of honey:

1. The high sugar content reduces the available water present in the honey drying out bacteria.
2. The low pH of honey makes it too acidic for the taste of most microbes.
3. Bees add the enzyme glucosoxidase to honey that produces hydrogenperoxide, a natural bleach. This destroys yeast that could have dealt with a lack of water and the acidic environment.
4. Special bee proteins such as “Bee Defensin-1” guard against microbial incursion. All these levels combined provide honey with its own in-built defence.

Bee’s Unique Secret Weapon

There are a few honey varieties which have even more protection. They have a special secret. Manuka honey from New Zealand contains the Unique Manuka Factor™ (UMF™), which is derived from a plant component found in the nectar of the Manuka flower. The nectar of Manuka flowers contains Dihydroxyaceton (DHA), which during the ripening of honey converts to Methylglyoxal (MGO), a natural antibacterial. That gives Manuka honey its extra punch against microbes and makes it the most durable honey in the world.

The next time you reach for a spoonful of honey, contemplate the dedication that went into creating these golden decadent energy stores, and say a quick thank you to the bees.

References:
Kwakman PHS, te Velde AA, de Boer L, Vandenbroucke-Grauls CMJE, Zaat SAJ (2011) Two Major Medicinal Honeys Have Different Mechanisms of Bactericidal Activity. PLoS ONE 6(3): e17709.doi:10.1371/journal.pone.0017709.
Van Eaton, C. (2014). Manuka: the biography of an extraordinary honey. Auckland: Exisle Publishing

Article: Gregor Steinhorn

Photographs: Dr Ralf Schlothauer"