according to Henrik Krehenwinkel, an assistant professor at the Department for Biogeography at Trier University in Germany, investigation of tea leaves is part of a larger and quite recent discipline known as the study of environmental DNA, or eDNA for short.

Figure 1: The essence of a hundred species of insects can be found in tea bag

Figure 1 shows that there are bugs in your cup of tea. Not whole bugs (hopefully not). But the essence of a hundred species of insects can be found in that tea bag you buy from the store.It’s called environmental DNA, and it’s not just on your tea leaves. It’s also in the air you breathe.Insects leave marks on the plants they interact with, specifically their DNA. Exposed to the elements, DNA can quickly degrade. [1]

It is deformed by the Sun’s ultraviolet rays and chewed up by enzymes. But in plant specimens that were carefully collected and kept in dry and cool storage, this trace has a better chance at surviving. A museum’s plant collection fits the bill, but so do tea leaves.

First, DNA is extracted from the sample. Then a section of it is amplified via the polymerase chain reaction (PCR), which acts like a photocopy machine churning out stacks of duplicates of a specific page. Finally, the amplified DNA is sequenced, and the letter-by-letter sequence is matched to a virtual database to identify the culprit.

Using this technology, the German team tested green tea, dandelion tea, samples from European beech trees, chamomile, mint, and parsley to see which predator, herbivore, pest, and casual visitor might have come into contact with them.

From these plant specimens, they recovered DNA from a total of 1,279 species, with the majority seemingly having been present before harvest and a small number of species typically tagging along during storage. [2]

Krehenwinkel said that out of the commercially available herbs and tea they analyzed using the eDNA analysis, they found DNA of up to 400 different types of insects in a single tea bag.They examined herbs and teas for their study because these commercial products are made from crushed and dried leaves, unlike heavily processed coffee, which probably has little DNA left.

They bought multiple versions of the same product from different brands to ensure each tea had a range of origins and maximize the number of insect species they could find. Their analysis showed that the majority of the DNA in tea leaves is from the tea plant itself, but there is a tiny fraction of insect DNA, which means that the tea is not dripping with pesticides. [3]

References:

1. https://www.mcgill.ca/oss/article/environment/when-drinking-tea-you-get-mouthful-bug-dna
2. https://www.technologynetworks.com/applied-sciences/news/theres-dna-from-hundreds-of-insects-in-your-tea-363969
3. https://www.sciencetimes.com/articles/38892/20220720/over-400-different-insect-species-single-tea-bag-dna-analysis.htm

Cite this article:

Sri Vasagi K (2022), DNA Traces of Bug in a Cup of Tea, Anatechmaz, pp. 382