Effects of selected bacterial cultures on safety and sensory traits of Nocellara Etnea olives produced at large factory scale

This work investigates the effects of different combinations of selected lactic acid bacteria strains on Lactobacillus species occurrence, on safety and on sensory traits of natural green table olives, produced at large factory scale. Olives belonging to Nocellara Etnea cv were processed in a 6% NaCl brine and inoculated with six different bacterial cultures, using selected strains belonging to Lactobacillus plantarum, Lactobacillus paracasei and Lactobacillus pentosus species. The fermentation process was strongly influenced by the added starters and the identification of lactic acid bacteria isolated throughout the process confirms that L. pentosus dominated all fermentations, followed by L. plantarum, whereas L. casei was never detected. Pathogens were never found, while histamine and tyrosine were detected in control and in two experimental samples. The samples with the lowest final pH values showed a safer profile and the most appreciated sensory traits. The present study highlights that selected starters promote prevalence of L. pentosus over the autochthonous microbiota throughout the whole process of Nocellara Etnea olives. •The fermentation process was strongly influenced by the mixed cultures added.•L. pentosus species dominated the whole process.•L. casei was never detected, independently from the added starters.•Histamine and tyrosine were detected mostly in control samples.•Sensory analysis confirmed that olives inoculated with L. paracasei plus L. pentosus exhibited the most appreciated traits.