Are foods safer than smoking


A report from our everyday laboratory work

Hanna Marks


The CVUA Stuttgart repeatedly finds residues of the pesticide active ingredient nicotine, which is no longer permitted in the EU, in fruit and vegetables. In addition to the targeted use of nicotine as a plant protection agent or as tobacco stock as a supposedly ecological agent, the nicotine levels can also result from the natural levels of the plant itself or from contamination with tobacco dust or smokers' hands. Tests by the CVUA Stuttgart show the extent of contamination.


Application or Contamination?

For unprocessed fruit and vegetables, with the exception of fresh herbs, a maximum residue level for the insecticide nicotine of 0.01 mg / kg set by the EU in Regulation (EC) No. 396/2005 applies. Since the beginning of 2017, the CVUA Stuttgart has examined a total of 259 samples of unprocessed fruit and vegetables (without fresh herbs) for nicotine and found a total of 19 abnormal findings above the legally stipulated maximum residue level. Taking into account the analytical fluctuation range of 50%, 6 of the 19 suspicious samples surely exceeded the maximum amount and were objected to.


Origin of the samples
Total number of samples
> 0.01 mg / kg and ≤ 0.02 mg / kg
> 0.02 mg / kg ***
EU (excluding Germany)
Third countries
Sum of all samples

* Herbs have a different maximum residue level and are not listed in the table.

** 0.01 mg / kg generally corresponds to the limit of quantification and the maximum content

*** The maximum residue level for nicotine has been safely exceeded after taking into account the analytical fluctuation range of 50%.


We can legally judge the samples based on the analysis results, but the measured levels say nothing about how the insecticide got into the sample - through its use as a pesticidal active ingredient, through contamination or through natural production of the plant itself?


Don't forget to wash your hands

Nicotine occurs naturally in the tobacco plant and, to a lesser extent, in other nightshade plants such as potatoes, tomatoes and eggplants. A natural occurrence of nicotine is being discussed for various other plants, such as porcini mushrooms and tea, but there is still no scientific evidence for this. Contamination from nearby tobacco fields or tobacco processing facilities is considered more likely. The use of self-made tobacco stock has already been highlighted in our internet article "Nicotine from tobacco - a" natural "remedy against plant pests?". Even individual cigarette butts in the field can lead to a not inconsiderable content in the food [1]. The cigarette butts get into the field primarily when they are harvested. But what are the possible ways in which food can be contaminated in everyday life?


Fig. 1: Salad - but no cigarette, please!


Perhaps a customer treats himself to a cigarette before doing their weekly shopping. Then the customer looks for the most beautiful head of lettuce - takes the head of lettuce in his hand, turns and turns it until he is sure that this is now the most beautiful head of lettuce of all. The CVUA Stuttgart simulated this situation for lettuce, apples and peaches, among other things, and then measured the nicotine levels. For this purpose, the food was picked up partly in a moist state and partly in a dry state after smoking a cigarette. When smoking before touching the peaches, the glowing side of the cigarette was held close to the palm of the hand between puffs - the hands came into greater contact with the nicotine.


Fig. 2: Nicotine levels in lettuce, apple, peach without or after contact with smoker's hands


The experiment shows that in dry foods no or comparatively little nicotine is transferred to the apple or peach. If, on the other hand, the food is moist, significant nicotine levels can be detected. Nicotine is a very polar pesticide and therefore easily soluble in water. A maximum residue level of 0.01 mg / kg applies to the three foods. This is exceeded for all three foods after contact with the moist food after smoking a cigarette. With more intensive contact by touching and cutting the moist food, somewhat higher levels were found in lettuce and peach.


While apples naturally have a smooth surface, lettuce usually has a fairly large, irregular surface, which also increases the contact with the skin when the food is touched. Due to the larger surface and the resulting increased contact with the hands contaminated with nicotine, a higher degree of nicotine contamination is conceivable in lettuce compared to apples. If one assumes a contamination and not an application, this is also reflected in our test results - 10 of the 19 maximum levels exceeded were found in leafy vegetables.


Even if the experiment of the CVUA Stuttgart is only a model experiment, it shows that after smoking a cigarette, relevant levels of nicotine can be transferred to the food - therefore, the following applies: Don't forget to wash your hands before handling food. This is also recommended from a general hygienic point of view.


When working in the laboratory and handling samples, we naturally wear disposable gloves so that contamination with nicotine is impossible.


Info box

The insecticide nicotine

Nicotine is a neurotoxin and binds to the so-called acetylcholine receptors in the brain, which are specialized binding sites on the cells for certain biochemical signaling processes. The substance causes, among other things, an increase in the respiratory rate, blood pressure and heart rate and also promotes the tendency for blood to clot, which increases the risk of thrombosis [2,3].

Due to its high toxicity, nicotine has not been approved as an active ingredient in pesticides in the EU since 2010. In order to estimate possible acute toxic risks in the event of short-term exposure, the amount of residues ingested when a food is consumed is compared with the so-called acute reference dose (ARfD). The ARfD for nicotine is 0.0008 mg per kg body weight [3].

With a nicotine content of 0.021 mg / kg green lettuce and thus a guaranteed exceedance of the maximum residue level, the ARfD is already used to 99.9% for small children according to the calculation using the EFSA PRIMo model revision 3. If the ARfD is exhausted to more than 100%, then a health impairment due to high consumption of the food cannot be ruled out with the necessary certainty [4].



Anja Barth, Sahra Söhnholz, Bärbel Illg


Photo credit

CVUA Stuttgart, pesticide laboratory



[1] Uptake of nicotine from discarded cigarette butts - A so far unconsidered path of contamination of plant-derived commodities, Selmar et al., Environmental Pollution 238, 2018

[2] German Cancer Research Center: How nicotine works (accessed on January 2, 2019)

[3] EFSA Statement: Potential risks for public health due to the presence of nicotine in wild mushrooms, The EFSA Journal RN 286, 1-47, 2009

[4] EFSA model for chronic and acute risk assessment, in the current version (as of January 2019: "PriMo Revision 3" as MS Excel file)


Article first published on January 29, 2019