These days, seasonality has little meaning when you step foot into the grocery store. Our global food market allows us the privilege to choose from a great variety of produce year round. Unfortunately, though, there is some risk involved with imported produce from countries where pesticide use may not follow strict regulations like those enforced in the U.S. This was exactly the case with the 2008 crop of dried wild mushrooms that Europe imported from China.
A recent finding by the European Food Safety Authority regarding the presence of highly detectable nicotine levels found in mushrooms sent red flags sailing in the European Commission. Although this phenomenon currently only concerns Europe, it is still of great interest to consumers and manufactures in the U.S.
Of the wild mushrooms tested by European food companies in 2008, a whopping 99% contained levels of nicotine that exceeded maximum residue limits or MRL – the safety limit set by individual countries regarding tolerable levels of pesticide residue on foods (the European Union and USDA have separate MRL tolerances).
While is it not clear what caused the presence of nicotine in these mushrooms, a number of factors, including accidental contamination during the drying process, are being examined. Another potential culprit is pesticide use.
Nicotine as a Pesticide?
Derived from the tobacco plant, nicotine is an alkaloid that has been used as a pesticide since at least the 15th century. Its main use originally was in greenhouses or enclosed spaces, where a smoke canister was set to allow the nicotine-laced smoke to fill the space. This process targeted pests like whiteflies without harming the plants.
In the U.S., nicotine is no longer acknowledged as an effective commercial pesticide. In fact, the FDA is currently processing the final cancellation for its use on non-food crops. The last U.S. food use registrations were cancelled in 1994, as were the residue tolerance levels. Currently the MRL used in the U.S. is a default 0.01 mg/kg. The EU is phasing out nicotine pesticides as well. They have proposed .035 mg/kg as the natural concentration of nicotine in fresh wild mushrooms that could be acceptable for consumption.
Effect on Humans
Nicotine is usually associated with cigarettes, which also contain up to 4,000 other disease-causing chemicals, giving nicotine – and its addictive properties – a bad reputation. But at trace levels, pure nicotine is virtually harmless and has been thought by some to even provide health benefits.
Those who eat a varied and balanced diet actually consume trace amounts of nicotine on a daily basis. It is a naturally occurring compound (at very low levels) in tomatoes, potatoes, cauliflower, eggplant, chili peppers and some teas.
High levels of nicotine can be very toxic when ingested orally, and its toxicity is dose responsive. Consuming greater than 60 mg/kg (the amount contained in four cigarettes) is potentially lethal in adults. In the case of the Chinese mushrooms, the residual amount detected was minor (.5 mg/kg), though still enough to induce mildly increased heart rate, dizziness, and headache – and therefore not considered to be safe for consumption.
In theory, because of its natural derivation, nicotine should prove harmless to the environment. However, in practice this is not the case. In areas where pesticides containing nicotine were widely used, bees, an insect critical in the pollination and lifecycle of our crops, were abandoning their hives, thus not able to perform their critical function. The effects of nicotine-based pesticides are detrimental to bee colonies, and there has also been a noted decrease in honey production, as well as huge losses in income for beekeepers.
Countries not included in the jurisdiction of the European Union or the United States, like China, continue to use nicotine to combat pests – a practice that will hopefully change in light of these findings. The U.S. screens imported canned mushrooms from China, but it is still a good idea for retailers to advise consumers to thoroughly wash their produce to remove unwanted and potentially harmful residues.