Impact of Olive Leaf Yellowing Associated Virus on Olive (Olea europaea L.) Oil

Among the 15 virus species detected in olive trees, Olive leaf yellowing associated virus (OLYaV) is found with high incidence and frequency in Southern Italy in particular. Effects of OLYaV on virgin olive oil yield and quality of Leccino and Ottobratica cultivars in the Calabria region (Southern Italy) are analyzed. Oil yield, free acidity, number of peroxides, spectrophotometric indices, total content of chlorophylls and carotenoids, total phenol content, composition of the fatty acids, total tocopherols, and total sterols content are determined on oil obtained from olive fruits collected in healthy/virus-free and OYLaV-infected trees. Almost all analyzed oil parameters are not statistically different with some exceptions. Oils derived from 'Ottobratica' OLYaV-infected plants have free acidity significantly lower than oil from healthy plants. K-232 of oil from virus-free 'Leccino' trees is significantly lower than oil from infected trees. Even though some quality parameter differences between healthy and OLYaV-infected oils are found, it is important to highlight that all oils can be considered in extra virgin olive oil category, within the UE maximum limit acceptance range. Results suggest a no negative interference by OYLaV in oil yield and quality, except for K-232 values, whereas surprisingly suggest a positive effect of virus infection on free acidity parameter. Practical Applications: Based on the evidence that OYLaV does not interfere negatively in oil yield and quality parameters, it seems appropriate that the European Union Council Directives (2014/96/EU, 2014/97/EU, 2014/98/EU) introduced in the last olive certification scheme only ArMV, CLRV, and SLRSV. The application of compulsory EU directive, in Italy as in other countries, will improve the facilities of olive plants commercialization, guaranteeing enough their sanitary status. The findings here reported support the suggestion that the Italian Ministry of Agriculture could be less restrictive in voluntary Italian regulation (D.M. 20/11/2006).