Old wine contains old – now banned – pesticides

What is it about?

Professor Pieter Spanoghe's research group, together with colleague Erik Meers (both faculty of Bioscience Engineering at Ghent University), looked for residues of chemical and biological pesticides in old French wines. Every bottle examined contains double traces of at least one substance that has disappeared from the market for years. The results nicely illustrate the evolution of the use of crop protection products in the last century.

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Photo by Riccardo Bernucci on Unsplash

Photo by Riccardo Bernucci on Unsplash

Why is it important?

Wines are one of the few agricultural products that allow historical use of crop protection products to be mapped. They are like old photographs of how we used to work in the field (or vineyard). The 80 bottles studied all predate the year 2000 - the oldest two were bottled as early as 1937. The grapes for these wines were grown in times when a lot of ancient pesticides were authorised and used to protect wine production from diseases, pests and weeds, a far cry from today's strict legislation. Because of the alcohol in wine, pesticides are preserved there for a long time. Every bottle contained traces of at least one pesticide that has since disappeared from the market for years. We have also seen a shift in the method of plant protection over the years. In the bottles of the 1960s, we detect a few broad-spectrum pesticides. Thereafter, the number of agents per bottle gradually increases. In the 1990s, we find wines containing 10 to more residues. These agents, in use at that time, are very specific and were therefore combined with others to achieve total control. They no longer control all diseases and pests at once, as broad-spectrum agents did before. The results reflect the trend, partly as a result of increasingly stringent regulation, from excessive use of unhealthy substances in high doses with a major impact on ecosystems, towards targeted and dosed use of more specific and less harmful substances. A trend that continues to this day. The survey concludes with a reassurance for all wine lovers. This is primarily about old wines. We do not drink these on a daily basis and certainly not in large quantities. Moreover, the evaluation of the health risk of the presence of traces of pesticides showed that for practically all wines we have nothing to worry about. The percentage of alcohol in wine is many times more toxic than any chemical or biological crop protection agent the research group found in it.

Perspectives

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The study reflects the ambiguous situation of how we as a society view crop protection and pesticide use. Today, nobody turns a blind eye when food products come on the market and contain pesticides that are banned for use. Even if there is no risk to public health, they are immediately taken off the shelves and destroyed. In the case of old wines, it is obvious that controlling their trade is difficult. Therefore, we accept the presence of old pesticides in those wines and do not even consider it at all when we drink a glass.

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