In silico logistic model for table olive related microorganisms as a function of sodium metabisulphite, cinnamaldehyde, pH, and Type of acidifying agent

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 Reviewe

Lactic Acid Bacteria and Yeast Inocula Modulate the Volatile Profile of Spanish-Style Green Table Olive Fermentations

In this work, Manzanilla Spanish-style green table olive fermentations were inoculated with Lactobacillus pentosus LPG1, Lactobacillus pentosus Lp13, Lactobacillus plantarum Lpl15, the yeast Wickerhanomyces anomalus Y12 and a mixed culture of all them. After fermentation (65 days), their volatile profiles in brines were determined by gas chromatography-mass spectrometry analysis. A total of 131 volatile compounds were found, but only 71 showed statistical differences between at least, two fermentation processes. The major chemical groups were alcohols (32), ketones (14), aldehydes (nine), and volatile phenols (nine). Results showed that inoculation with Lactobacillus strains, especially L. pentosus Lp13, reduced the formation of volatile compounds. On the contrary, inoculation with W. anomalus Y12 increased their concentrations with respect to the spontaneous process, mainly of 1-butanol, 2-phenylethyl acetate, ethanol, and 2-methyl-1-butanol. Furthermore, biplot and biclustering analyses segregated fermentations inoculated with Lp13 and Y12 from the rest of the processes. The use of sequential lactic acid bacteria and yeasts inocula, or their mixture, in Spanish-style green table olive fermentation could be advisable practice for producing differentiated and high-quality products with improved aromatic profile.Gobierno de España-OliFilm-AGL-2013-48300-

Survival of foodborne pathogens in natural cracked olive brines

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 Reviewe

Susceptibility and resistance of lactic acid bacteria and yeasts against preservatives with potential application in table olives

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 Reviewe

Effect of green Spanish-style Manzanilla packaging conditions on the prevalence of the putative probiotic bacteria Lactobacillus pentosus TOMC-LAB2

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 PilotPeer reviewe

Understanding the transcriptomic response of Lactiplantibacillus pentosus LPG1 during Spanish-style green table olive fermentations

Lactiplantibacillus pentosus (Lbp. pentosus) is a species of lactic acid bacteria with a great relevance during the table olive fermentation process, with ability to form non-pathogenic biofilms on olive epidermis. The objective of this work is to deepen into the genetic mechanisms of adaptation of Lpb. pentosus LPG1 during Spanish-style green table olive fermentations, as well as to obtain a better understanding of the mechanisms of adherence of this species to the fruit surface. For this purpose, we have carried out a transcriptomic analysis of the differential gene expression of this bacterium during 60 days of fermentation in both brine and biofilms ecosystems. In brines, it was noticed that a total of 235 genes from Lpb. pentosus LPG1 were differentially expressed during course of fermentation and grouped into 9 clusters according to time-course analysis. Transport and metabolism of carbohydrates and amino acids, energy production, lactic acid and exopolysaccharide synthesis genes increased their expression in the planktonic cells during course of fermentation. On the other hand, expression of genes associated to stress response, bacteriocin synthesis and membrane protein decreased. A total of 127 genes showed significant differential expression between Lpb. pentosus LPG1 planktonic (brine) and sessile (biofilms) cells at the end of fermentation process (60 days). Among the 64 upregulated genes in biofilms, we found genes involved in adhesion (strA), exopolysaccharide production (ywqD, ywqE, and wbnH), cell shape and elongation (MreB), and well as prophage excision. Deeping into the genetic bases of beneficial biofilm formation by Lpb. pentosus strains with probiotic potential will help to turn this fermented vegetable into a carrier of beneficial microorganisms to the final consumers

Fortification of table olive packing with the potential probiotic bacteria Lactobacillus pentosus TOMC-LAB2

© 2014 Rodríguez-Gómez, Romero-Gil, García-García, Garrido-Fernández and Arroyo-López. Dairy products are currently the main carriers of probiotic microorganisms to the human body. However, the development of new matrices for probiotic delivery is convenient for intolerant to milk (or its derivatives) and those requiring low-cholesterol diet consumers. The present work focused on the fortification of previously fermented green Spanish style olives with the autochthonous putative probiotic bacteria Lactobacillus pentosus TOMC-LAB2. The fortification was carried out by inoculating the bacteria into the packing brines using Manzanilla fruits from three different processes: (i) spontaneously fermented (F1), (ii) fermented using L. pentosus TOMC-LAB2 as starter (F2), and (iii) spontaneously fermented and then thermally treated (F3). Data showed that all inoculated treatments had higher population levels (5.49, 4.41, and 6.77 log10 cfu/cm2) than their respective controls (1.66, 4.33, and 0.0 log10 cfu/cm2, for F1, F2, and F3 treatments, respectively). The presence of L. pentosus TOMC-LAB2 on olive surface was confirmed by rep-PCR, with a recovery frequency at the end of the shelf life (200 days) of 52.6, 57.9, and 100.0% for F1, F2, and F3 treatments, respectively. Thus, results obtained in this work show the ability of this microorganism to survive under packing conditions for long period of times as well as to colonize the olive surface which is the food finally ingested by consumers. This opens the possibility for the development of a new and simply probiotic fortified olive product.he research leading to these results has received funding from the EU’s Seventh Framework Programme [FP7/2007-2013] under grant agreement no 243471 (PROBIOLIVES). We also thank the Spanish Government for financial support (projects AGL2009-07436/ALI, and AGL2010-15529/ALI partially financed by European regional development funds, ERDF), and the Junta de Andalucía (through financial support to group AGR-125). Thanks to JOLCA and ASEMESA for supplying the fruits and their own expertise for the development of this work. Francisco N. Arroyo-López wishes to express thanks for his Ramón y Cajal postdoctoral research contract (Spanish government).Peer Reviewe

Use of a D-optimal design with constrains to quantify the effects of the mixture of sodium, potassium, calcium and magnesium chloride salts on the growth parameters of Saccharomyces cerevisiae.

The combined effect of NaCl, KCl, CaCl(2), and MgCl(2) on the water activity (a (w)) and the growth parameters of Saccharomyces cerevisiae was studied by means of a D-optimal mixture design with constrains (total salt concentrationsor = 9.0%, w/v). The a (w) was linearly related to the concentrations of the diverse salts; its decrease, by similar concentrations of salts, followed the order NaClCaCl(2)KClMgCl(2), regardless of the reference concentrations used (total absence of salts or 5% NaCl). The equations that expressed the maximum specific growth (mu (max)), lag phase duration (lambda), and maximum population reached (N (max)) showed that the values of these parameters depended on linear effects and two-way interactions of the studied chloride salts. The mu (max) decreased as NaCl and CaCl(2) increased (regardless of the presence or not of previous NaCl); however, in the presence of a 5% NaCl, a further addition of KCl and MgCl(2) markedly increased mu (max). The lambda was mainly affected by MgCl(2) and the interactions NaCl x CaCl(2) and CaCl(2) x MgCl(2). The further addition of NaCl and CaCl(2) to a 5% NaCl medium increased the lag phase while KCl and MgCl(2) had negligible or slightly negative effect, respectively. N (max) was mainly affected by MgCl(2) and its interactions with NaCl, KCl, and CaCl(2); MgCl(2) stimulated N (max) in the presence of 5% NaCl while KCl, NaCl, and CaCl(2) had a progressive decreasing effect. These results can be of interest for the fermentation and preservation of vegetable products, and foods in general, in which this yeast could be present

Microbiological and Physicochemical Changes in Natural Green Heat-Shocked Aloreña de Málaga Table Olives

11 Páginas; 5 Tablas; 6 FigurasPreserving the highly appreciated natural freshness of Aloreña de Málaga table olives and preventing their progressive darkening during processing is a major challenge. In this work, heat-shocked (60°C, 5 min) fruits were processed according to the three denominations referred to in the Protected Designation of Origen (cured, fresh green, and traditional) and their characteristics compared with those that followed the habitual industrial process (controls). The results revealed that the effects of the heat treatment on the evolution of pH, titratable acidity, salt, sugar, organic acid, ethanol content, texture, and color of fruits as well as on microbial populations (yeasts and lactic acid bacteria) were slight in the case of the fresh green and cured presentations. However, the differences between heat-shocked and its control were remarkable in the traditional process. Notably, the heat treatment favored lactic acid fermentation, retention of the green appearance of the fruits, stability during packaging, and led to the highest sensory evaluation. The metagenomic analysis carried out at the end of the fermentation revealed the presence in all samples of three genera (Lactobacillus, Pediococcus, and Celerinatantimonas) which encompassed most of the sequences. The number of Lactobacillus sequences was statistically higher (p ≥ 0.05) in the case of traditional heat-shocked fruits than in its control.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. FA-L wishes to express thanks to the Spanish government for his RyC postdoctoral research contract while VR-G would like to thank ceiA3, Spanish Government, Bank of Santander, IG-CSIC and ‘Aloreña de Málaga’ Olive Manufacturing Association for her predoctoral fellowship. Authors express their gratitude to Dr. Borja Sánchez (IPLA-CSIC) for his invaluable help in the metagenomic analysis.Peer reviewe

Microbial stability and quality of seasoned cracked green Aloreña table olives packed in diverse chloride salt mixtures.

This work was conducted to determine the effect of the partial replacement of NaCl by KCl and CaCl2 (expressed as percentages, wt/vol) on the microbial stability and physicochemical characteristics of seasoned cracked olives using a simplex centroid mixture design. Neither Enterobacteriaceae nor lactic acid bacteria were found during the 50 days that olive packages were monitored. Therefore, microbial instability was considered due to the growth of yeasts, which were the only detected microorganisms; Saccharomyces cerevisiae and Pichia membranifaciens were the most relevant species. Yeasts decreased during the first 21 to 30 days after packing, but their populations rose to 3.5 log CFU/ml by the end of the storage period, clearly causing product deterioration. The partial substitution of NaCl with the other chloride salts slightly altered the phase of microbial inhibition and regrowth. Most of the quality characteristics were not affected by the use of the alternative salt mixtures, but the pH values and Cl(-) concentrations in brine decreased as the CaCl2 concentration increased. Hence, seasoned cracked table olives can be produced using a lower proportion of NaCl without causing significant changes in the shelf life and product quality, although further detailed studies are necessary to guarantee the stability of products packed with specific salt mixtures