The honey sting

As a consumer it’s hard for me not to feel inundated with claims that our food is “all-natural” or “chemical-free” or that we should buy certain “superfoods” for their health benefits.  We read labels and trust that the product we are buying is what we are truly getting.  As a scientist though I know that these claims are not all they promise to be.  Most consumers probably aren’t thinking about the authenticity of their food so it’s important for the scientific community help ensure that the food we eat is exactly what we think it is.  

Food fraud is a global problem.  For example, one of Australia’s largest honey producers and large  supermarket chains were accused of selling fake honey. When tested, almost half the products labeled “pure” and “100% honey” were revealed to have been tampered with or blended with other substances, such as sugar syrup.

“Adulterated honey isn’t honey at all.”
Phil McCabe, President of the International Federation of Beekeepers’ Association (Apimondia)

While this is incredibly disappointing, it was later magnified when the Australian Consumer and Competition Commission (ACCC) criticized the methods used in the study, calling them unreliable.  We know that food adulteration is a major problem in the global food chain, so why are “unreliable” methods being used to test for product authenticity? Let’s take a closer look at the situation.

What is honey exactly?
Honey is a thick mix of fructose and glucose known as nectar that bees extract from flowers. It’s the natural mix of pollens, nutrients and enzymes from both the flower and bee processing that makes honey unique.

So, what are these buzzwords “fake” and “adulterated,” and what do they mean with regards to honey? While not necessarily harmful, it can be deceptive when alternatives such as corn or sugar syrup are labeled the same as actual honey.  Food manufacturers are financially motivated to add fillers and sell the original product at a higher price in order to improve margins.  For example, Manuka honey is a rare honey valued for its unique taste and makeup, making it one of the most expensive honeys in the market. Diluted Manuka honey sold at the price point of the real thing is one real-world example of economically motivated food adulteration practice.

Are regulators paying attention?
The answer is yes.  In Europe for example, the Council Directive 2001/110/EC has one of the most stringent honey regulations. It outlines the legal definition of honey, composition criteria and labeling requirements. The directive also includes sugar content requirements:

• The combination of fructose and glucose should not be less than 60g/100g for blossom honey, and not less than 45g/100g for honeydew honey and related blends. 
• Sucrose content shall not exceed 5g/100g. However, higher limits have been established for several specific botanical sources, such as French honeysuckle, Eucalyptus and lavender¹.

Despite these types of regulations, shelves are still plagued by adulterated or mislabeled honey products.

How do we test for adulterated honey?

C4 Sugar Test
The C4 Sugar Test is an internationally accepted method to detect whether honey has been manipulated by adding sugars, primarily can sugar and high fructose corn syrup.  Essentially sugars produced from plants like sugar cane and corn are produced using a photosynthetic pathway called the “C4” pathway.  Nectar produced by bees, on the other hand, use a different “C3” pathway.  Since there is a measurable difference in the ratios of carbon isotopes arising from these two pathways this the test can identify whether C4 sugars have been added to the sample^2,3. 

Using technology to detect food fraud
Determining the authenticity of a food matrix is an important step. Because of the sensitivity requirements, a mass spectrometry-based solution can help. Utilizing QTOF technology allows us to screen food samples such as honey for all its ionizable constituents. Taking mass spec data through a statistical analysis such as NMR allows for comparison to a database or chemical model of authentic samples⁴.

A principal component analysis (PCA) on the data shows that chemical fingerprints of samples reveal differences in honey from various floral origins. We can also go further and use the data to identify small molecule markers and metabolites unique to certain strains. Some of these include polyphenols and antioxidants that may be desirable or beneficial components⁴.

The ability to spot food fraud is critical to ensuring the safety of products and confirming that we are getting what we pay for.  Regulators are enforcing strict limits on products and scientists are testing samples to validate authenticity.  So as consumers, it is up to us to continue reading labels to be sure that we are informed about what we are eating…now that is sweet!

References

1. https://ec.europa.eu/food/sites/food/files/safety/docs/oc_control-progs_honey_jrc-tech-report_2016.pdf
2. https://www.analytica.co.nz/Tests/Honey-Testing/C4-Sugars
3. https://www.analytica.co.nz/News-Resources/c4-sugars-answers-to-commonly-asked-questions
4. https://www.sciencedirect.com/science/article/pii/S0924224418302449