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© 2015 Medina-Pradas and Arroyo-López. Table olives have an enormous importance in the diet and culture of many Mediterranean countries. Albeit there are different ways to produce this fermented vegetable, brining/salting, fermentation, and acidification are common practices for all of them. Preservation methods such as pasteurization or sterilization are frequently used to guarantee the stability and safety of fermented olives. However, final products are not always subjected to a heat treatment. Thus, microbiota is not always removed and appropriate levels of acidity and salt must be obtained before commercialization. Despite the physicochemical conditions not being favorable for the growth of foodborne pathogens, some illness outbreaks have been reported in the literature. Street markets, inappropriate manipulation and storage conditions were the origin of many of the samples in which foodborne pathogens or their metabolites were detected. Many authors have also studied the survival of pathogens in different styles of table olive elaboration, finding in general that olive environment is not appropriate for their presence. Inhibitory compounds such as polyphenols, low availability of nutrients, high salt content, low pH levels, bacteriocins, or the addition of preservatives act as hurdles against undesirable microorganisms, which contribute to obtaining a safe and good quality product. ; This paper has received funding from Junta de Andalucía regional Government through the PrediAlo project (AGR-7755: www.predialo.science.com.es) and EU's Seventh Framework Program (FP7/2007-2013) under grant agreement n°243471 (PROBIOLIVES: www.probiolives.eu). FA-L wishes to express thanks to the Spanish government for his Ramón y Cajal postdoctoral research contract, while EM-P would like to thank The Junta de Andalucía for his postdoctoral research contract. ; USD 875 APC fee funded by the EC FP7 Post-Grant Open Access Pilot ; Peer Reviewed

7 pages, 2 figures, 3 tables.-- Printed version published May 2009. ; In this study, we performed an analysis of the ability of four Saccharomyces cerevisiae and one S. bayanus var. uvarum strains, isolated from different industrial processes, to ferment increasing amounts of fructose (from 0 to 70%, w/v). Overall yeast growth was estimated by integration of the area under optical density vs. time curves. Subsequently, this parameter was modeled by means of a substrate inhibition model. All strains showed a similar behavior against fructose concentration in spite of their different origins, but with slight differences. The optimum fructose concentrations to stimulate yeast growth were obtained between 4.33 and 6.05%, while the maximum concentrations above which growth was completely inhibited were attained between 59.56 and 63.85%. Statistically, model parameters calculated for wine yeast strains were significantly different than those obtained for yeasts from Agave and table olive fermentations, except for the maximum inhibitory concentration. The methodology used in this work could be useful for the industry in general as a first procedure to select yeast strains with higher fructose preferences or tolerances, and especially for winemakers, where the risk of spoilage increases by the presence of a marked residual fructose concentration in the finished wine. ; This work was supported by Generalitat Valenciana (project GV2008-037) and the Spanish Government (projects AGL2006-12703-CO2-01 and 02/ALI). ; Peer reviewed

A probabilistic/logistic model, based on binary data (growth/no growth), was used to assess the effects of sodium metabisulphite (SM) and cinnamaldehyde (CIN; 0-1000 mg/L) against the main microbial groups found in table olive environment [lactic acid bacteria (LAB), yeasts, and Enterobacteriaceae], according to pH (range 3.5-5.0), and type of acidifying agent (HCl or pyruvic acid). The inhibitory effect of SM depended on the pH while that of CIN was scarcely influenced by it (except for LAB). LAB were more sensitive to SM, while yeasts were to CIN. The use of pyruvic acid for correction of pH always produced a reduction (compared to HCl) of the inhibitory power of both preservatives. The in silico models for HCl showed that, at pH 4.0, and growth probability 0.01, the LAB population might be inhibited by the presence in the medium of 150 mg/L SM or 1000 mg/L CIN, while in the case of yeasts, 450 mg/L SM, or 150 mg/L CIN are required. No growth of Enterobacteriaceae was observed at this (or lower) pH level. The results obtained may contribute to the stabilization of non-thermally treated table olive packaging. ; This research has received funding from INTERACEITUNA (Organización Interprofesional de la Aceituna de Mesa, Spain) and the Junta de Andalucía. FNAL thanks to the Spanish Government and CSIC for his Ramón y Cajal postdoctoral research contract, while VR thanks the AgriFood Campus of International Excellence (ceiA3), Bank of Santander, Spanish Government and "Aloreña de Málaga" Olive Manufacturing Association for her pre-doctoral fellowship (training and formation program of Ph.D. in companies). ; Peer Reviewed

This study investigates the application of electro-coagulation and ozonation technologies for the partial depuration of ferrous solutions deriving from the color fixation stage of ripe olive processing. Different operational conditions were investigated along with the possibilities of combining the two techniques sequentially. In electro-coagulation the best depuration conditions were obtained using a current density of 25 mA cm-2 for 40 min; COD elimination reached 30%, the phenols and color of the solutions were also considerably reduced and the dissolved Fe was completely removed. On the contrary, the microbial population mainly composed of lactic acid bacteria and yeasts, hardly decreased. The application of ozonation also reduced the total phenols, color and COD of solutions, but did not decrease the iron concentration. However, it considerably affected the microbial population in a higher proportion than electro-coagulation. In light of the results obtained, the best working conditions consist of applying 40 min electro-coagulation with aluminum in the anode and iron in the cathode at 25 mA cm-2 current density, followed by the storage of a partially purified solution bubbling ozone to reduce the microorganism population and even eliminate it completely when 6 g O3 L-1 were added. This would allow for a possible reuse of these solutions for preparing new fixing color solutions or as cover brine in packaging. © 2014 Elsevier B.V. All rights reserved. ; This work was supported by the Spanish Government (project AGL2010-15494 partially financed from European regional development funds, ERDF) and Junta de Andalucía (through financial support to group AGR-125). ; Peer Reviewed

This work reports the survival (challenge tests) of foodborne pathogen species (Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica) in Aloreña de Málaga table olive brines. The inhibitions were fit using a log-linear model with tail implemented in GInaFIT excel software. The olive brine had a considerable inhibitory effect on the pathogens. The residual (final) populations (Fp) after 24 h was below detection limit (<1.30 log cfu/mL) for all species assayed. The maximum death rate (k) was 9.98, 51.37, 38.35 and 53.01 h, while the time for 4 log reductions (4D) was 0.96, 0.36, 0.36 and 0.24 h for E. coli, S. aureus, L. monocytogenes and S. enterica, respectively. Brine dilutions increased Fp and 4Dr, while decreased k. A cluster analysis showed that E. coli had an overall quite different behaviour being the most resistant species, but the others bacteria behaved similarly, especially S. aureus and S. enterica. Partial Least Squares regression showed that the most influential phenols on microbial survival were EDA (dialdehydic form of decarboxymethyl elenolic acid), HyEDA (EDA linked to hydroxytyrosol), hydroxytyrosol 4-glucoside, tyrosol, and oleoside 11-methyl ester. Results confirm the adverse habitats of table olives for foodborne pathogenic microorganisms. ; The research leading to these results has received funding from the Junta de Andalucía through PrediAlo Project (AGR7755: www.predialo.science.com.es) and FEDER European funds. Thanks to Copusan S.C.A (Alozaina, Málaga, Spain) for supplying the fruits and facilities for the development of experiments. FNAL wishes to thank the Spanish Government and CSIC for his Ramón y Cajal postdoctoral research contract, while VRG thanks the AgriFood Campus of International Excellence (ceiA3), Bank of Santander, Spanish Government and 'Aloreña de Málaga' Olive Manufacturing Association, for her pre-doctoral fellowship (training program of Ph.D. in companies). Authors also express their gratitude to F. Rodríguez-Gómez, M. Brenes, and C. Romero from Instituto de la Grasa (CSIC, Seville) for their invaluable help during HPLC analyses. ; Peer Reviewed

In the present study, a dose-response model was used to investigate the susceptibility (NIC) and resistance (MIC) of the lactic acid bacteria and yeast populations with respect to five chemical preservatives (fumaric and pyruvic acids, cinnamaldehyde, sodium metabisulphite and natamycin) with potential application in table olives. Results were compared with respect to potassium sorbate, a well-known preservative habitually used in olive packaging. Sodium metabisulphite was the most efficient preservative to control lactic acid bacteria growth (MIC, 50 ppm), followed by cinnamaldehyde (1060 ppm) while pyruvic acid required higher concentrations (3211 ppm). Natamycin (25 ppm) was highly efficient against yeasts, followed by cinnamaldehyde (125 ppm), potassium sorbate (553 ppm), sodium metabisulphite (772 ppm) and pyruvic acid (3038 ppm). Fumaric acid, in the range assayed (0–2000 ppm), did not show any inhibitory effect against these two microbial groups. This survey presents for the first time a comparative study of the efficiency of potential preservatives to control the growth of table olive related microorganisms. Further studies should be performed to validate their effects and interactions in the food matrix. ; The research leading to these results has received funding from INTERACEITUNA (Organización Interprofesional de la Aceituna de Mesa, Spain) and the Junta de Andalucía. FNAL thanks to the Spanish Government and CSIC for his Ramón y Cajal postdoctoral research contract, while VRG thanks the AgriFood Campus of International Excellence (ceiA3), Bank of Santander, Spanish Government and 'Aloreña de Málaga' Olive Manufacturing Association for her pre-doctoral fellowship (training and formation program of Ph.D. in companies). ; Peer Reviewed

21 Pa´ginas.-- 10 Figuras.-- 3 Tablas ; Table olives can suffer different types of spoilage during fermentation. In this work, a multi-statistical approach (standard and compositional data analysis) was used for the study of the volatile organic compounds (VOCs) associated with altered (butyric, sulfidic, and putrid) and non-altered (normal) Manzanilla Spanish-style table olive fermentations. Samples were collected from two industrial fermentation yards in Seville (Spain) in the 2019/2020 season. The VOC profiles of altered (n = 4) and non-altered (n = 6) samples were obtained by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Ninety-one VOCs were identified and grouped into alcohols (30), esters (21), carbonyl compounds (12), acids (10), terpenes (6), phenols (6), sulfur compounds (2), and others (4). The association of the VOCs with spoilage samples depended on the standard or compositional statistical methodology used. However, butyric spoilage was strongly linked by several techniques to methyl butanoate, ethyl butanoate, and butanoic acid; sulfidic spoilage with 2-propyl-1-pentanol, dimethyl sulfide, methanol, 2-methylbutanal, 2-methyl-2-butenal, ethanol, 2-methyl-3-buten-2-ol, and isopentanol, while putrid was mainly related to D-limonene and 2-pentanol. Our data contribute to a better characterisation of non-zapatera spoiled table olive fermentations and show the convenience of using diverse statistical techniques for a most robust selection of spoilage VOC markers. ; This research was funded by Spanish Government (TOBE Project: grant number RTI2018-100883-B-I00). ; Peer reviewed

13 Páginas.-- 2 Tablas.-- 5 Figuras ; 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. ; The research has received funding from the Spanish Government (Project TOBE RTI2018-100883-B-I00: www.tobeproject.csic.es). ; Peer reviewed

The effect of the main environmental factors governing wine fermentation on the fitness of industrial yeast strains has barely received attention. In this study, we used the concept of fitness advantage to measure how increasing nitrogen concentrations (0 to 200 mg N/liter), ethanol (0 to 20%), and temperature (4 to 45°C) affects competition among four commercial wine yeast strains (PDM, ARM, RVA, and TTA). We used a mathematical approach to model the hypothetical time needed for the control strain (PDM) to out-compete the other three strains in a theoretical mixed population. The theoretical values obtained were subsequently verified by competitive mixed fermentations in both synthetic and natural musts, which showed a good fit between the theoretical and experimental data. Specifically, the data show that the increase in nitrogen concentration and temperature values improved the fitness advantage of the PDM strain, whereas the presence of ethanol significantly reduced its competitiveness. However, the RVA strain proved to be the most competitive yeast for the three enological parameters assayed. The study of the fitness of these industrial strains is of paramount interest for the wine industry, which uses them as starters of their fermentations. Here, we propose a very simple method to model the fitness advantage, which allows the prediction of the competitiveness of one strain with respect to different abiotic factors. © 2014, american Society for Microbiology. All Rights Reserved. ; This work has been financially supported by grants AGL2010-22001-C02-01 and PROMETEO/2009/019, from the Spanish government and Generalitat Valenciana respectively, awarded to JMG. EGR also wishes to thank the Spanish government for her FPI grant, while FNAL thanks the Spanish government for his Ramon y Cajal postdoctoral contract. ; Peer Reviewed

11 pages, 3 figures, 3 tables.-- Article first published online: 8 SEP 2010 ; In this work, we apply statistical modelling techniques to study the influence of increasing concentrations of ethanol on the overall growth of 29 yeast strains belonging to different Saccharomyces and non-Saccharomyces species. A modified Gompertz equation for decay was used to objectively estimate the noninhibitory concentration (NIC) and minimum inhibitory concentration (MIC) for the assayed strains to ethanol, which are related to the susceptibility and resistance of yeasts to this compound, respectively. A first ANOVA analysis, grouping strains as a function of their respective Saccharomyces species, revealed that S. cerevisiae was the yeast with the highest, and statistically significant, ethanol resistance value. Then, a second factorial ANOVA analysis, using the origin of strains (wild or fermentative) and their taxonomic classification (S. cerevisiae, S. paradoxus or S. bayanus var. uvarum) as categorical predictor variables, showed that no significant differences for the NIC and MIC parameters were found between both ecological niches within the same species, indicative that these physiological characteristics were presumably not modified throughout the adaptation to human-manipulated fermentative environments. Finally, differences among selected strains with respect to ethanol tolerance were correlated to the initial contents of unsaturated fatty acids, mainly oleic acid. ; This work was supported by Generalitat Valenciana (project PROMETEO/2009/019) and the Spanish Government (projects AGL2009-12673-CO2-01, AGL2009-12673-CO2-02 and AGL2007-65498-C02-02, to A.Q., E.B. and J.M.G., respectively). F.N. Arroyo-López also thanks the Spanish Government (MICINN) for his 'Juan de la Cierva' postdoctoral research contract. ; Peer reviewed

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. ; 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). 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 Reviewed

This work focuses on the persistence of the putative probiotic bacteria Lactobacillus pentosus TOMC-LAB2 on green Spanish-style Manzanilla olives according to different packaging conditions and storage temperatures. The lactic acid bacteria population decreased with time but the highest survival counts (and lowest yeasts) at the end of storage (8 months) were observed in plastic pouches under nitrogen atmosphere and glass jars with brine stored at 20°C. Molecular techniques showed a 100% presence of the putative probiotic bacteria in biofilms adhered to olive epidermis, while it was absent in PPB (plastic pouches with brine) and in olives stored at 7°C. No changes in NaCl, pH or combined acidity were observed during the storage except for a slight increase in titratable acidity at 20°C. The color of the fruits was stable but degraded at 20°C for olives in plastic pouches with brine. ; The research leading to these results has received funding from the EU's Seventh Framework Program (FP7/2007-2013) under grant agreement n°243471 (PROBIOLIVES) and the Junta de Andalucía (through financial support to group AGR-125). Thanks to JOLCA for supplying the fruits and the packages and to ASEMESA for its support. FNAL thanks the Spanish Government and CSIC for his Ramón y Cajal postdoctoral research contract, while VRG wishes to thank the AgriFood Campus of International Excellence (ceiA3), Bank of Santander, Spanish Government, and 'Aloreña de Málaga' Olive Manufacturing Association for her predoctoral fellowship (training program of PhD in companies). ; EUR 1,172 APC fee funded by the EC FP7 Post-Grant Open Access Pilot ; Peer reviewed

Yeasts are unicellular eukaryotic microorganisms with a great importance in the elaboration on many foods and beverages. In the last years, researches have focused their attention to determine the favourable effects that these microorganisms could provide to table olive processing. In this context, the present study assesses, at laboratory scale, the potential technological (resistance to salt, lipase, esterase and β-glucosidase activities) and probiotic (phytase activity, survival to gastric and pancreatic digestions) features of 12 yeast strains originally isolated from Greek natural black table olive fermentations. The multivariate classification analysis carried out with all information obtained (a total of 336 quantitative input data), revealed that the most promising strains (clearly discriminated from the rest of isolates) were Pichia guilliermondii Y16 (which showed overall the highest resistance to salt and simulated digestions) and Wickerhamomyces anomalus Y18 (with the overall highest technological enzymatic activities), while the rest of strains were grouped together in two clearly differentiated clusters. Thus, this work opens the possibility for the evaluation of these two selected yeasts as multifunctional starters, alone or in combination with lactic acid bacteria, in real table olive fermentations. © 2014 Elsevier Ltd. ; The research leading to these results has received funding from the Spanish Government (Ramón y Cajal program), and the Junta de Andalucía (through financial support to group AGR-125). S. Bonatsou and F.N. Arroyo-López wish to express thanks to the European Erasmus program and Ramón y Cajal postdoctoral research contract (Spanish Government), respectively. ; Peer Reviewed

© 2014 Society of Chemical Industry. BACKGROUND: Zinc chloride has been used previously as a preservative in directly brined olives with promising results. However, this is the first time that the effects of ZnCl 2 addition (0-1gL -1 ) on green Spanish-style table olive (cv. Manzanilla) packaging has been studied. RESULTS: The presence of ZnCl 2 affected the physico-chemical characteristics of the products; the presence of the Zn led to lower pH values (particularly just after packaging) and titratable and combined acidity values than the control but did not produce clear trends in the colour parameters. No Enterobacteriaceae were found in any of the treatments evaluated. At the highest ZnCl 2 concentrations, the lactic acid bacteria were inhibited while, unexpectedly, its presence showed a lower effect than potassium sorbate against the yeast population. Regardless of the use of potassium sorbate or ZnCl 2 , the packages had a reduced microbial biodiversity because only Lactobacillus pentosus and Pichia galeiformis were found at the end of the shelf life. With respect to organoleptic characteristics, the presentations containing ZnCl 2 were not differentiated from the traditional product. CONCLUSION: Zinc chloride was less efficient than potassium sorbate as a yeast inhibitor in green Spanish-style olives, showing clear presentation style dependent behaviour for this property. Its presence produced significant changes in chemical parameters but scarcely affected colour or sensory characteristics. ; This work was supported by the Spanish Government (projects AGL2009-07436/ALI and AGL2010-15494/ALI, partially financed by European regional development funds, ERDF), and Junta de Andalucía (through financial support to group AGR-125). J. Bautista-Gallego and F.N. Arroyo-López wish to thank the CSIC and the Spanish government for their JAE predoctoral fellowship and Ramón y Cajal postdoctoral research contract, respectively. ; Peer Reviewed

© 2014 Elsevier Ltd. Zygosaccharomyces rouxii is an osmophilic yeast responsible for a large amount of economic loss in high sugar food production. Statistical modelling techniques were used in the present study to assess the individual effects of different chemical preservatives (potassium sorbate, sodium benzoate, dimethyldicarbonate, vanillin, ferulic, p-coumaric and caffeic acids) to control the growth of a cocktail of five yeast strains belonging to this species and isolated from spoilt concentrated grape juices. None of the preservatives assayed were able to completely inhibit the Z. rouxii growth. However, the mathematical models obtained in a high sugar culture media showed that especially four preservatives (potassium sorbate, sodium benzoate, dimethyldicarbonate and vanillin) were the best options to control the growth of this microorganism, obtaining a maximum reduction on yeast growth of approximately 40%. On the contrary, p-coumaric and caffeic acids were the preservatives with the lower effects, which only showed a maximum growth reduction percentage of approximately 15%. Results obtained in this paper could be very useful for industry for a better control of this spoilage yeast in concentrated grape juice. ; This research was supported by the Technological ProjectMZASJ51007: Support for Regional Viticulture Development – INTA. The authors wish to kindly thank to Dra. Amparo Querol (IATA-CSIC) for her generous scientific advice. M.C. Rojo is a Doctoral student Fellow of CONICET. F.N. Arroyo-López wants to thank CSIC and Spanish government for his Ramón y Cajal postdoctoral research contract. ; Peer Reviewed