1 research outputs found
Assessment of the bacterial community in directly brined Aloreña de Málaga table olive fermentations by metagenetic analysis
This study uses an ¿omics¿ approach to evaluate the bacterial biodiversity changes during fermentation process
of natural green cracked Aloreña de Málaga table olives, from raw material to fermented fruit. For this purpose,
two industries separated by almost 20 km in Guadalhorce Valley (Málaga, Spain) were analysed for obtaining
both brines and fruit samples at different moments of fermentation (0, 7, 30 and 120 days). Physicochemical
and microbial counts during fermentation showed the typical evolution of this type of processes, apparently
dominated by yeasts. However, high-throughput barcoded pyrosequencing analysis of V2¿V3 hypervariable region
of the bacterial 16S rRNA gene showed at 97% identity the presence of 131 bacterial genera included in 357
operational taxonomic units, not detected by the conventional approach. The bacterial biodiversity was clearly
higher in the olives at the moment of reception in the industry and during the first days of fermentation, while
decreased considerably as elapse the fermentation process. The presence of Enterobacteriaceae and
Lactobacillaceae species was scarce during the four months of study. On the contrary, the most important
genus at the end of fermentation was Celerinatantimonas in both brine (95.3% of frequency) and fruit (89.4%)
samples, while the presence of well-known spoilage microorganisms (Pseudomonas and Propionibacterium)
and halophilic bacteria (Modestobacter, Rhodovibrio, Salinibacter) was also common during the course of fermentation. Among the most important bacterial pathogens related to food, only Staphylococcus genus was found at lowfrequencies (b0.02% of total sequences). Results showthe need of this type of studies to enhance our knowledge of the microbiology of table olive fermentations. It is also necessary to determine the role played by these species not previously detected in table olives on the quality and safety of this fermented vegetable.The research leading to these results has received funding from Junta de Andalucía Government through the PrediAlo project (AGR-7755: www.predialo.science.com.es) and FEDER European funds. FNAL wishes to express thanks to the Spanish government for his RyC postdoctoral research contract while VRG would like to thank ceiA3, Spanish Government, Bank of Santander, IG-CSIC and ‘Aloreña de Málaga’ Olive Manufacturing Association for her pre-doctoral fellowship.Peer Reviewe