Tomato fruit: friend or foe? Lessons learnt on emerging safety issues

Tomatoes are a star ingredient of the Mediterranean diet and evoke a powerful association with health benefts related to the content of benefcial compounds as lycopene. However, their consumption might hide some threats related to the contami nation by fungi able to produce toxic metabolites. In fact, in a recent investigation, samples of fresh and dried tomatoes pro duced in the Apulia region (southern Italy) and sent to Euro pean markets proved to be contaminated by Alternaria spp. and related mycotoxins. These fnding prompted the assess ment of the contamination by mycotoxigenic fungi of tomatoes cultivated in a conducive (warm and humid) environment as the greenhouse, which is growing in popularity to counter act seasonality and extreme weather events. It was found that Alternaria, Aspergillus, and Penicillium were the most repre sented genera. Particularly, Alternaria strains were mostly A. alternata morphotype alternata, able to produce alternariol and alternariol monomethyl ether. Aspergillus strains included species A. westerdijkiae, A. ochraceus, and A. occultus, able to produce ochratoxin A (OTA), and A. welwitschiae, able to pro duce OTA and fumonisins. The majority of Penicillium strains was represented by P. olsonii, not able to produce regulated mycotoxins. Commercial formulations were tested in order to control those pathogens and related decays. Potassium bicar bonate and the combination peracetic acid+hydrogen peroxide proved to prevent fungal growth completely. The same formu lations applied by dipping on tomato fruit against A. alternata, the most aggressive pathogen, were efective against disease incidence and severity. These promising results support their use in larger-scale trials.