The bitter truth about pine nuts

Did you know that certain pine nut species are unsuitable for human consumption? In fact, some pine nuts leave people with a bitter or metallic taste in their mouth that can last for days, or even weeks!

In this article, Nina Constantine, Director of Food & Environment at Eurofins Genomics, explains how DNA-based testing techniques can prevent inedible pine nuts ending up in restaurant dishes or on supermarket shelves.

You may be familiar with pine nuts – these teardrop-shaped delights have a sweet, buttery flavour and are frequently used in pesto-making or sprinkled on top of pasta dishes and salads.

Unfortunately, certain types of these tiny nuts can cause dysgeusia, commonly known as taste distortion. While they usually taste normal upon consumption, some people may notice a bitter taste lingering in their mouth one to three days after the meal, that is worsened by consuming other food and drinks. The intense metallic taste, similar to the flavour of coins, can remain for up to two weeks!

Therefore, it’s vital to know what species of pine nuts you’re selling or buying. Well, Nina Constantine from Eurofins Genomics is here to debunk the world of pine nuts and explain how DNA testing can reduce the chances of dishing up dodgy pine nuts.

“DNA-based methods are becoming more popular in the food testing industry,” says Nina. “They are routinely used to identify genetically modified organisms of pathogens within food products, as well as for the identification of a variety of fungal, microbial, animal, and plant species used in food production. As such, DNA-based methods can also be very helpful in combatting food fraud or other deceptive practices,” Nina describes.

“Eurofins Genomics frequently receives requests to test pine nut samples and ensure that certain pine nut species are not present, namely P. armandii, P. massoniana, and P. tabulaeformis, which are not suitable for human consumption,” says Nina. “Clients are particularly concerned about P. armandii, as this species is widely believed to cause taste distortion. We also use DNA-based methods to check that varieties of pine nuts such as P. gerardiana are not being passed off as more expensive species such as P. pinea,” Nina adds.

So, how does pine nut DNA testing work? “Our method of testing analyses DNA markers, or known sequence differences, that have been identified between various species of pine nuts,” Nina explains. “It was a challenge for Eurofins Genomics to find reliable DNA markers that would allow us to differentiate between edible and inedible pine nut species. We gathered and analysed reference material of known origin for dozens of species across Europe, North America, and Asia,” Nina reflects. The outcome was a DNA-based method that can accurately distinguish between pine nut species.”

“Trusted testing techniques such as DNA-based methodologies are necessary to help food buyers make informed and safe decisions. In addition to pine nuts, Eurofins Genomics can test numerous varieties of rice, wheat, spices, and other food products,” Nina concludes.

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To learn more about Eurofins Genomics’ DNA-based food traceability and safety solutions, visit our website.