Lactobacillus pentosus is the dominant species in spoilt packaged Aloreña de Málaga table olives

• This study reports a new spoilage in olive packages and its characterization.
• The genotypes of the microbial populations were determined by molecular techniques.
• Enterobacteriaceae, yeasts and LAB were initially present, but only LAB counts increased.
• Packaging conditions favour Lactobacillus pentosus growth against the initial Lactobacillus plantarum.
• A specific biotype of Lactobacillus pentosus was predominant in the spoilt product.

The present study focused on investigating a peculiar spoilage of traditional Aloreña de Málaga table olives characterized by the formation of whitish and soft regions on the olive surface. To determine its causes, the main microbiological and physicochemical changes in 50 commercial packages were monitored until the alteration in appearance (63 days). Colour and firmness of fruits deteriorated progressively in the packaged olives during storage. Sugar in brines (7.5 g/L) remained stable during the first month and then decreased gradually (5.0 g/L) while, in parallel, the lactic acid bacteria population and titratable acidity increased. After two months of storage, evidence of spoilage was noticed, coinciding with the maximal lactic acid bacteria populations in fruit (>6.5 log10 CFU/g). The spoilage affected ∼25% of the fruits within packages. The microbial species detected in the product after packaging were Enterobacter gergoviae and Lactobacillus plantarum among bacteria, and Candida tropicalis, Candida parapsilosis, and Lodderomyces elongisporus among the yeasts while Lactobacillus pentosus was the dominant species in the spoilt packages. A specific biotype of L. pentosus was only detected in the damaged fruits. Further studies will be made to confirm the association between the spoilage and the presence of this L. pentosus biotype.