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In this work, a total of 72 samples of non-thermally treated commercial table olives were obtained from different markets of the world. Then, prokaryotic diversity in olive biofilms was investigated by metataxonomic analysis. A total of 660 different OTUs were obtained, belonging to Archaea (2.12%) and Bacteria domains (97.88%). From these, 41 OTUs with a proportion of sequences ≥ 0.01% were studied by compositional data analysis. Only two genera were found in all samples, Lactobacillus, which was the predominant bacteria in the biofilm consortium (median 54.99%), and Pediococcus (26.09%). Celerinatantimonas, Leuconostoc, Alkalibacterium, Pseudomonas, Marinilactibacillus, Weissella, and the family Enterobacteriaceae were also present in at least 80% of samples. Regarding foodborne pathogens, only Enterobacteriaceae, Vibrio, and Staphylococcus were detected in at least 91.66%, 75.00%, and 54.10% of samples, respectively, but their median values were always below 0.15%. Compositional data analysis allowed discriminating between lye treated and natural olive samples, as well as between olives packaged in glass, PET and plastic bags. Leuconostoc, Celerinatantimonas, and Alkalibacterium were the bacteria genera with a higher discriminant power among samples. These results expand our knowledge of the bacteria diversity in olive biofilms, providing information about the sanitary and hygienic status of this ready-to-eat fermented vegetable. [ABSTRACT FROM AUTHOR]

In this work, we have used a metataxonomic analysis to study the bacterial biodiversity in three types of commercial dressing and ingredients habitually used in table olive packaging. The bioinformatics analysis showed that salt samples (marine and spring) had the highest biodiversity indexes, followed by the aromatic herbs (thyme, oregano, and fennel) and finally by fermented dressing samples (garlic, pepper, and pepper paste). In salt samples, a significant high presence of Cytophagia , Sphingobacteria, Deltaproteobacteria and Halobacteria classes was observed. On the contrary, the presence of Bacilli class in fermented dressing samples was significantly higher compared to the other samples. Finally, the abundance of Gammaproteobacteria was statistically higher in the samples of herbs. At genus or family taxonomic level, Pseudomonas and diverse non-assigned genus of the Enterobacteriaceae family predominated in many samples of herbs. In fermented dressing samples, a diverse genus belonging to the Enterobacteriaceae family appeared in a high relative abundance in pepper paste and garlic, and the presence of Vibrio sp. was detected in pepper. However, Lactobacillus, Weisella, and Pediococcus were the predominant genera found in many of these fermented samples. Salinibacter was the most representative genus in both types of salt samples. Multivariate analysis (PCA) of the metataxonomic data sets discriminated well the samples belonging to the three different groups, showing a high proportion of sequences shared by samples-group. This survey reports for the first time the presence of new bacterial species not previously related to table olive processing, as well as the presence of others which could compromise the stability of olive packaging. • Metataxonomic analysis has provided a deep knowledge of the microbiota present in olive dressing. • Pseudomonas and diverse non-assigned genus of Enterobacteriaceae predominated in aromatic herbs. • Lactobacillus , Weisella, and Pediococcus were the predominant genera found in many fermented dressing samples. • Salinibacter was the most representative genus found in samples of salt. • Olive dressing includes spoilage microorganisms that may alter the stability of table olive packaging. [ABSTRACT FROM AUTHOR]

This work applies metataxonomic, standard statistics, and compositional data (CoDa) techniques to study the bacterial diversity of spoiled and normal Spanish-style table olive fermentations, analysing a total of 10-tons of industrial fermentation containers from two processing yards. Forty percent were affected by butyric, sulfidic, or putrid spoilage, while 60% followed the ordinary fermentation course. The samples were obtained at 30 days of fermentation, determining their 16S rRNA gene Amplicon Sequence Variant compositions (ASVs). The butyric containers showed a bacterial profile strongly associated with the genera Enterococcus , Leuconostoc , and Atlantibacter , but also with Lactiplantibacillus and Melissococcus , and less confident to Raoultella , Enterobacter , Serratia , and Celerinatantimonas. The sulfidic fermentation was linked to Alkalibacterium and, to a lesser extent, Marinilactibacillus and the absence of Lactiplantibacillus. Putrid spoilage was mainly related to Halolactibacillus and Alkalibacterium. Sulfidic/putrid (together) differed from butyric spoilage by the presence of Alkalibacterium / Marinilactibacillus as well as by Halomonas / Halanaerobium. Lactiplantibacillus dominated normal fermentations, but Vibrio was also frequently found (0–46%), apparently not causing any alteration. These results contribute to a better microbial characterisation of non-zapatera spoiled table olive fermentations. They also suggest using several statistical techniques to discriminate normal vs spoiled fermentations adequately. • Bacterial profiles of spoiled industrial table olive fermentation vessels was studied. • Butyric spoilage was mainly related to Enterococcus , Leuconostoc , and Atlantibacter. • Sulfidic spoilage was primary associated with Alkalibacterium. • Putrid spoilage was linked to Halolactobacillus and Alkalibacterium. • Propionibacterium , Bacillus or Pseudomonas were not detected in the spoiled vessels. [ABSTRACT FROM AUTHOR]