Microbial Evolution during Storage of Seasoned Olives Prepared with Organic Acids with Potassium Sorbate, Sodium Benzoate, and Ozone Used as Preservatives

Abstract

The effect of potassium sorbate, sodium benzoate, and ozone in combination with citric, lactic, and acetic acids on the microbial population of seasoned table olives of the olive ‘Aloreña’ cultivar was studied in both fresh (FF) and stored fruits (SF). The inactivation/growth curves were modeled and the biological parameters estimated, with yeast used as the target microorganism. Regardless of the acid added, potassium sorbate showed a general inactivation effect on yeasts in the products prepared from both FF and SF. Sodium benzoate had a rapid inactivation effect with FF, but with SF, it was effective only in the presence of acetic acid. A strain of Issatchenkia occidentalis was found that was resistant to the combination of this preservative with citric or lactic acids. In FF, ozone showed an initial marked inhibition against yeasts, but later, yeasts were again able to grow. In SF, ozone was a strong inactivating agent when it replaced any of the traditional preservatives. Lactic acid bacteria were always absent in products prepared from FF and apparently were not affected by the different preservative agents in those prepared from SF. The behavior of yeasts and lactic acid bacteria populations in commercial products were similar to those found in experimental treatments.