New insights into microbial diversity of the traditional packed table olives Aloreña de Málaga through metataxonomic analysis

Aloreña de Málaga is a table olive speciality characterised by its natural freshness and short shelf life. In this work, we have applied a metataxonomic approach to unravel the microbial diversity of bacterial and fungi populations through the shelf-life of traditional packed Aloreña de Málaga. A significant increase of lactic acid bacteria and mesophilic aerobic populations was observed during shelf life, reaching the maximum population levels (4-5 log10 CFU) at the end of study (260 days). On the contrary, it was reported a rapid reduction of yeast & mould populations. The use of a metataxonomic analysis based on the amplification of 16S (bacteria) and ITS (fungi) regions, revealed a low diversity for both microbial groups. Lactiplantibacillus (65.05 ± 8.65% in brine vs 58.70 ± 15.70% in fruit), Pediococcus (28.17 ± 7.36% in brine vs 27.20 ± 15.95% in fruit), and Celerinatantimonas (4.64 ± 1.08% in brine vs 11.82 ± 18.17% in fruit) were the main genera found among bacteria, noticing an increase in Lactiplantibacillus and a reduction in Celerinatantimonas populations through shelf-life. On the other hand, Citeromyces was the dominant fungi genus (54.11 ± 2.00% in brine vs 50.91 ± 16.14% in fruit), followed by Candida (8.80 ± 2.57% in brine vs 12.32 ± 8.61% in fruit) and Penicillium (6.48 ± 1.87% vs 8.48 ± 4.43% in fruit). No food-borne pathogen genera were detected in any of the samples analysed, indicating the high level of food safety found in this ready-to-eat fermented vegetable. Data obtained in this work will help to design new strategies for the control of microbial populations during the shelf-life of Aloreña de Málaga.