Survival of micro-organisms in extra virgin olive oil during storage

When newly produced from the grinding of the olive fruits, olive oil contains solid particles and micro-drops of vegetation water which settle during the preservation of the product. The present research has demonstrated that, together with the suspended material in the extra-virgin olive oil, there are numerous micro-organisms, primarily yeasts. Fungi belonging to the genus Aspergillus, were occasionally observed, while bacteria were not found. When olive oil was artificially inoculated with Candida wickerhamii isolated from the same habitat, it was found that the yeasts were able to grow in the micro-drops of vegetation water or distilled water suspended in the olive oil. Furthermore, it was shown that the partial elimination of the sediments in the oil, carried out with cotton filtration by the bottling companies, allows an appreciable reduction of the number of micro-organisms present in the extra-virgin olive oil.