What is NPA in Manuka honey?
Did you know that Manuka honey is not the same everywhere? Moreover, batches from one place can also be different. So, what factors vary? For this product, it’s the level of antibacterial activity. In this article we’ll consider the index that defines it.
What is NPA?
It means the non-peroxide activity of honey. This is what gives the product its special antiseptic properties. You may see the abbreviation and a number on the tags of jars. We would like to go further than just using difficult definitions and terms that mean nothing to an ordinary person. That’s why we will try to explain them first, to be as clear as possible.
The key point is that every kind of honey has a sort of antimicrobial qualities. They are caused by peroxide activity. But manuka honey is unique because it also has non-peroxide activity (NPA) that gives it such features. To get the idea and see the difference, let’s learn more about them.
It is peculiar to almost every type of honey. The antibacterial effect is provided by low pH level, high osmolarity and mostly by hydrogen peroxide. It is produced with the help of a glucose oxidase enzyme. The agent uses glucose and oxygen to release antiseptic qualities of hydrogen peroxide. Thanks to this, honey can be used to inhibit minor infections. It doesn’t damage tissue when killing bacteria.
But the problem is that this compound is sensitive to light and heat. One more weak side is breaking down after contacting blood, saliva and serum. Due to this, antimicrobial properties are lost.
This is NPA that gives manuka honey special features. It comes from containing methylglyoxal (MGO) in the nectar of this plant. The agent is generated from dihydroxyacetone (DHA) during the ripening. This quality is also used for another rating - MGO.
Methylglyoxal has an antibacterial effect as well and it is not destroyed under the influence of light, heat or body fluids. That’s why honey saves its antiseptic properties even after hydrogen peroxide is neutralized. This feature is called ‘non-peroxide activity’, which is a base for the same-name rating.
Meaning of NPA rating
This index is marked on tags as an abbreviation and a number near it that shows the strength of manuka honey. The idea is the following: the rating shows the antimicrobial effect that the product has, compared to the effect that a phenol solution of a certain concentration would have. It is measured in %. In other words, the index number is equal to the % of phenol content in water. For example, NPA 10+ means that honey has the same effect on bacteria as a 10% phenol solution.
How is it assessed? For this purpose there is used an agar well diffusion method. The product is placed in a well, made in an agar plate with microorganisms. When the diffusion starts, the researchers see to what extent the activity of bacteria is inhibited. The results are compared with the effect of a certain concentration of a phenol solution. Based on this, they make a conclusion about the strength of manuka honey.
Since NPA depends on methylglyoxal, its level is related to the MGO rating. For example, 10+ non-peroxide activity is peculiar to the honey with MGO 260+. It is supposed that significant antiseptic qualities appear when the activity is 10+. The higher the level, the stronger the product.
What causes different properties? The quality depends on a few factors:
- Plants - in what conditions they grow, environment, climate, etc.
- Bees - their age and colony health.
- Conditions in which the product is processed and stored.
But the most important factor for NPA is whether the nectar was gathered only from manuka bloom or it was mixed with other species. It influences the concentration of MGO since it is present only in this kind of plant.
How to choose manuka honey
First, we would like to mention that not all kinds of this product have non-peroxide activity. Some producers add peroxide activity and NPA scores to achieve higher ratings. They do it for marketing reasons and to raise a price. That’s why read the tags more carefully. Apart from that, there are three rules:
- Make sure that you know what NPA means and choose your type.
- Ask for a certificate. To make sure that this product is genuine, request a document to check if the claimed quality is proven with the laboratory test. You can also examine it by color and smell. If it is dark brown and has a burnt or caramelized flavor, it is highly possible that the honey is old or was heated to increase NPA artificially. It’s important because after such procedures enzymes are destroyed.
- Read ours article about MGO - this will help you to choose the best manuka honey type.
You’ll do it with Biosota
Our honey is gathered on farms in the remote Australian forest. It helps to achieve high quality and provide products with different ratings for various needs. Every batch is properly tested in laboratories, that’s why all the NPA and MGO marks are proved with certificates. So, you can be sure that you pay exactly for what you get.