title: Assessment of the bacterial community in directly brined Aloreña de Málaga table olive fermentations by metagenetic analysis.
abstract: 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 20km in Guadalhorce Valley (Málaga, Spain) were analysed for obtaining both brines and fruit samples at different moments of fermentation (0, 7, 30 and 120days). 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 low frequencies (<0.02% of total sequences). Results show the 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.
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), University Campus Pablo de Olavide, Building 46, Ctra, Utrera, km 1, 41013 Seville, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Medina
authors.affiliation: Regulatory Council of PDO Aloreña de Málaga Table Olives, C/ Dehesa, 80, 29560 Pizarra, Malaga, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Ruiz-Bellido
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), University Campus Pablo de Olavide, Building 46, Ctra, Utrera, km 1, 41013 Seville, Spain; Regulatory Council of PDO Aloreña de Málaga Table Olives, C/ Dehesa, 80, 29560 Pizarra, Malaga, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Romero-Gil
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), University Campus Pablo de Olavide, Building 46, Ctra, Utrera, km 1, 41013 Seville, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Rodríguez-Gómez
authors.affiliation: Crop Protection Department, Institute for Sustainable Agriculture (IAS-CSIC), Avenida Menéndez Pidal s/n, Campus Alameda del Obispo, 14004 Cordoba, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Montes-Borrego
authors.affiliation: Crop Protection Department, Institute for Sustainable Agriculture (IAS-CSIC), Avenida Menéndez Pidal s/n, Campus Alameda del Obispo, 14004 Cordoba, Spain. Electronic address: blanca.landa@ias.csic.es.
authors.forename: B B
authors.initials: BB
authors.lastname: Landa
authors.affiliation: Food Biotechnology Department, Instituto de la Grasa (IG-CSIC), University Campus Pablo de Olavide, Building 46, Ctra, Utrera, km 1, 41013 Seville, Spain.
authors.forename: F N
authors.initials: FN
authors.lastname: Arroyo-López
mesh_terms: D001419:Bacteria / Q000235:genetics*; D044822:Biodiversity; D005285:Fermentation; D005516:Food Microbiology; D006801:Humans; D054892:Metagenome; D031658:Olea / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S; D012492:Salts; D013030:Spain; D015003:Yeasts / Q000235:genetics*
chemical_list: D012336:RNA, Ribosomal, 16S; D012492:Salts; C017082:brine
keywords: Aloreña de Málaga; Bacterial ecology; Celerinatantimonas; Olive fermentations; Pyrosequencing