TDK conference 2019

Chemical plant protection is one of the most polluting areas in agricultural production. Due to their use, pesticides can get into the vegetables during primary production and thus into the food chain, therefore they constitute a potential risk to the consumer’s health. Non-compliance with the legal regulations of pesticide use, their excess quantities, inadequate spraying techniques, and non-compliance with their withdrawal period will increase the pesticide content of the cultivated vegetables. It is extremely important from point of view of consumer health that the levels of pesticides do not exceed the MRLs in the vegetables and their products intended for consumption.

In our experiments, the plants were treated with Movento (spirotetramate) insecticide and Amistar Top (azoxystrobin, difenoconazole) fungicide at officially authorized concentrations and amounts. The depletion of pesticides was monitored in the food chain after individual and simultaneous application in the treated tomatoes and their product prepared from them (tomato juice), to investigate whether there is a kinetic interaction between them, changes in the elimination of each component, and thus corresponds to the official MRLs. Tomato cultivation was performed by hydroculture in a closed greenhouse, avoiding the influence of possible external environmental factors. Samples were prepared using the QuEChERS method and the chemicals were analysed by LC/MS method.

The concentrations of pesticides applied alone or simultaneously were below the MRL values after the withdrawal period in all investigated tomato samples.

In all cases, the concentration of spirotetramate in the tomato juice was very low (<1 g/kg), whether the product was used alone or in combination and whether the samples were exposed to heat or not. Azoxystrobin was below the detection limit in both untreated and heat-treated samples after the individual treatment, but trace amounts of it (<1 g/kg) were present in the untreated product after the combined treatment. The concentration of difenoconazole showed a decreasing tendency in the untreated tomato juice after individual and simultaneous application, but it was already below the detection limit in the heat-treated tomato juice.

In all samples of tomatoes and tomato juice tested, the pesticide residues were below the MRL, but the co-presence of pesticides modified the elimination of the individual compounds.

Summarising, the simultaneous application of the investigated pesticides can be safely used, their concomitant presence does not pose risk to the consumers’ health.