Local honey vs store-bought: what a DNA test revealed
I sent two samples of honey to lab. One sample came from a hive we manage in Durham, North Carolina. I harvested and extracted the honey myself on May 1st, 2023.
The other sample was from a bottle I bought at Walmart.
The lab—Jonah Ventures based in Boulder, Colorado—sequenced the plant DNA from the pollen in both samples using a technique known as metabarcoding to determine which plant species were present. A total of 14 species were detected in the local honey sample:
You might have noticed that "cherry" appeared twice on the report. When I inquired with the lab, they explained that metabarcoding is not a perfect science. The two cherries could be the same species, or two closely related species.
Metabarcoding targets specific DNA regions or “barcodes” that are very similar within a species but differ between species. Still, it is possible for two different species to have similar or even identical barcode sequences, especially if they are closely related.
That wasn’t the only anomaly on the report: a few plant species originally detected seemed unlikely for our region. For instance, the report indicated that 2.88% of the pollen came from olive plants. I have never heard of an olive plant growing in our area of the state.
Considering my local plant knowledge, I made these adjustments to the report which are reflected in the graphic above:
Are these plants necessarily where the nectar was collected from?
According to USDA research, a bee's collection of nectar from a plant doesn't match the pollen types in honey on a 1:1 basis. Some plants may be high nectar producers, but weak pollen producers. These plants would be under-represented in a DNA test like the one above.
In an effort to verify information advertised on honey labels, researchers have developed various methods for correcting the pollen data. These methods produce what are known as pollen coefficient (PC) values—but digging into PC values is beyond the scope of this mini experiment.
Now, what about the Walmart honey?
Only one plant species was detected in the Walmart honey: tobacco.
What does this suggest? This is unlikely to be honey from a tobacco farm; it's more probable that this honey underwent ultrafiltration.
Small-scale beekeepers filter their honey through plastic filters to remove bee legs, large bits of wax, wood splinters, and other debris. These mesh filters are typically around 400 microns in size: small enough to remove most unwanted impurities but large enough to allow pollen to pass through.
Ultrafiltration, on the other hand, involves heating the honey and passing it through a polymer-based membrane that removes pollen and enzymes. This results in a smoother and more transparent product that resists crystallization.
The store-bought honey we sent in for testing.
Is ultrafiltration bad?
The American Beekeeping Federation and the FDA don't agree on what defines honey. The FDA defines it as, "a syrupy substance made by bees from nectar or plant secretions."
Most beekeepers emphasize that real honey contains pollen, acting as a unique marker of authenticity, origin, and visited plants.
Ultrafiltration strips away the array of compounds and textures that make honey special.
But consumers vote with their dollars, and they resoundingly vote for light-colored honey that doesn’t crystallize. Unfortunately, this sets the stage for fraudulent honey. Honey ranks as the third-most adulterated food, trailing only behind olive oil and milk.
To boost profits, producers in some countries mix honey with corn or fructose syrup. Due to such concerns, the U.S. bans honey imports from China. But by ultrafiltering their honey, they can relabel it in an intermediary country, masking its real origin.
We're not claiming the Walmart honey we bought is counterfeit, cut with syrup.
However, what we can confidently state is that local honey is tangibly different than what you find in the store-bought bear: in taste, aroma, and yes, pollen content.
In the end, the purchase is yours to make.