Effects of olive storage and packaging on microbial and fatty acids profiles of olive oil produced in traditional mills in Morocco

The aim of this work was to evaluate the effects of storage time of olive fruits and packaging type on the microbial and chemical quality of virgin olive oil produced in traditional mills in Morocco. 72 samples of olive oil of Moroccan Picholine variety were recovered in PET and dark glass bottles and analyzed after 3 and 6 months of storage. Results indicated that mesophilic and psychrotrophic bacteria, yeasts and moulds showed similar profiles in both containers, while, indices of quality and saturated fatty acids (SFA) increased, and unsaturated fatty acids (UFA) decreased. Significant changes were shown in palmitic, stearic, and oleic acids. Furthermore, accelerated degradations of oils were observed in plastic container. Statistical analysis showed a strong negative correlation between UFA and SFA, free fatty acids contents (FFAs), K232 and K270. Discriminate analysis showed that storing olive fruits plays important role in the classification of olive oil. In fact, long storage linked to the presence of microorganisms was responsible for significant changes produced in fatty acids profile and olive oil quality.