Microbiological and biochemical profile of cv. Conservolea naturally black olives during controlled fermentation with selected strains of lactic acid bacteria

The effect of controlled fermentation processes on the microbial association and biochemical profile of cv. Conservolea naturally black olives processed by the traditional anaerobic method was studied. The different treatments included (a) inoculation with a commercial starter culture of Lactobacillus pentosus, (b) inoculation with a strain of Lactobacillus plantarum isolated from a fermented cassava product and (c) uninoculated spontaneous process. Microbial growth, pH, titratable acidity, organic acids and volatile compounds were monitored throughout the fermentation. The initial microbiota consisted of Gram-negative bacteria, lactic acid bacteria and yeasts. Inhibition of Gram-negative bacteria was evident in all processes. Both starter cultures were effective in establishing an accelerated fermentation process and reduced the survival period of Gram-negative bacteria by 5 days compared with the spontaneous process, minimizing thus the likelihood of spoilage. Higher acidification of the brines was observed in inoculated processes without any significant difference between the two selected starter cultures (113.5 and 117.6mM for L. plantarum and L. pentosus, respectively). L. pentosus was also determined as the major species present during the whole process of spontaneous olive fermentation. It is characteristic that lactic acid fermentation was also initiated rapidly in the spontaneous process, as the conditions of fermentation, mainly the low salt level (6%, w/v) favored the dominance of lactic acid bacteria over yeasts. Lactic, acetic and propionic were the organic acids detected by HPLC in considerable amounts, whereas citric and malic acids were also present at low levels and degraded completely during the processes. Ethanol, methanol, acetaldehyde, ethyl acetate were the major volatile compounds identified by GC. Their concentrations varied among the different treatments, reflecting varying degrees of microbial activity in the brines. The results obtained from this study could help the Greek table olive industry to improve the existing processing schemes in order to increase product consistency and quality expanding the international market for naturally black olives.     

Occurrence of Listeria monocytogenes in green table olives

Microbiological safety of green table olives from different cultivars, prepared by both the Spanish-style and biological methods and fermented with starter cultures of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus pentosus), was investigated. The fermentation process was monitored by measuring pH values, titratable acidities, and growth of lactic acid bacteria over time. During fermentation, lactic acid bacteria and yeasts were major microbial populations. Microbiological safety was evaluated by analysis for Listeria monocytogenes with the use of an enrichment method during storage (from 55 days to 18 months). Results demonstrated that L. monocytogenes can survive and grow in green table olives. L. monocytogenes was found in one of the commercial (thermally treated) samples analyzed and in all samples older than 2 months, irrespective of olive cultivar, lactic acid bacteria starter used, pH and titratable acidity of brine samples, or treatment applied.     

A study on the implications of NaCl reduction in the fermentation profile of Conservolea natural black olives

This study examined the impact of different mixtures of NaCl, KCl, and CaCl₂ on the fermentation profiles of Conservolea natural black olives. Five different combinations of chloride salts were investigated, namely (i) 8% NaCl (control treatment), (ii) 4% NaCl and 4% KCl, (iii) 4% NaCl and 4% CaCl₂, (iv) 4% KCl and 4% CaCl₂, and (v) 2.6% NaCl-2.6% KCl-2.6% CaCl₂. The changes in the microbial association (lactic acid bacteria, yeasts, Enterobacteriaceae), pH, titratable acidity, organic acids, volatile compounds, and mineral content in olive flesh were analyzed. Results demonstrated that all salt combinations led to vigorous lactic acid processes based on the obtained values of pH (3.9-4.2) and titratable acidity (0.70-0.86 g lactic acid per 100 ml brine). Organoleptic evaluation was a critical factor in the acceptability of the final product. Increasing concentrations of CaCl₂ or a combination of KCl and CaCl₂ rendered the product bitter with low acceptability by the taste panel. Only one combination of chloride salts (4% NaCl and 4% KCl) could finally produce olives with lower sodium content and good organoleptic attributes. The results of this study could be employed by the Greek table olive industry in an attempt to produce natural black olives with less sodium without affecting the traditional taste of fermented olives in order to meet consumers’ demand for low sodium dietary intake.     

Effect of different brining treatments on the fermentation of cv. Conservolea green olives processed by the Spanish-method

The effect of different initial brining conditions on the spontaneous fermentation of cv. Conservolea green olives was studied. The different treatments included: (a) brine acidification with 2 per thousand (v/v) lactic acid (control), (b) addition of 25 per thousand (v/v) 1n HCl (c) substitution of the initial brine by 20% (v/v) with a brine from a previous fermentation (brine re-use). Microbial growth, pH, titratable acidity and organic acids were monitored. Brine re-use process was the most effective in minimizing the likelihood of spoilage since it decreased the survival period of enterobacteria (24 days), followed by the HCl treatment (28 days) and the control (35 days). However, after 35 days of fermentation, pH values reached a plateau above 4.8 in all treatments indicating that supplementary treatments were necessary to enhance lactic acid fermentation and attain acidity/pH levels that would improve the physicochemical characteristics of the final product and ensure its safety. Addition of 1.5% (w/v) glucose in the HCl-treated and brine re-use processes as well as 5 per thousand (v/v) lactic acid in the control was performed. All supplementary treatments were effective in reducing pH to a final value of 4.3-4.5. However, glucose increased the final concentration of lactic acid in brine re-use and HCl-treated processes (73.4 and 67.8 mm, respectively) compared with the control that was lacking in acidity (44.7 mm), denoting a clear advantage of glucose over lactic acid as a supplement.     

Effect of potassium sorbate and sodium benzoate on microbial population and fermentation of black olives

Black olive fermentation characteristics and diffusion of preservatives into olives were evaluated in brines containing 500 ppm potassium sorbate, 1000 ppm sodium benzoate, 500 ppm sodium benzoate + 250 ppm potassium sorbate and no preservative (control). Changes in brine pH, acidity and microbial population (lactic acid bacteria, yeasts, moulds) were followed during fermentation and storage. Results indicated that K‐sorbate when used at 500 ppm concentration in black olive fermentation had a slight stimulatory effect on the growth of lactic acid bacteria. The yeast counts of brines containing 500 ppm K‐sorbate and 1000 ppm Na‐benzoate were lower than for the brine containing 250 ppm K‐sorbate + 500 ppm Na‐benzoate and for the control with no preservative, while mould growth was completely inhibited in all treatments during fermentation. Mould counts stayed below the detection limit (<10 cfu g⁻¹) during 214 days of vacuum‐packaged storage. Yeast counts showed a progressive decline within 28 days of storage and then stayed relatively constant in all treatments thereafter. The level of yeast population was higher in the control sample than in the sample containing both preservatives during storage. The diffusion of Na‐benzoate and K‐sorbate into the olives after equilibrium was 64% and 80% during fermentation respectively. © 1999 Society of Chemical Industry     

Use of starter cultures of lactic acid bacteria and yeasts in the preparation of togwa,a Tanzanian fermented food

Starter cultures of lactic acid bacteria (Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus fermentum, Lactobacillus plantarum and Pediococcus pentosaceus) and yeasts (Candida pelliculosa, Candida tropicalis, Issatchenkia orientalis and Saccharomyes cerevisiae) isolated from native togwa were tested singly or in combination for their ability to ferment maize-sorghum gruel to produce togwa. All species of bacteria showed an ability to ferment the gruel as judged by lowering the pH from 5.87 to 3.24-3.49 and increasing the titratable acidity from 0.08% to 0.30-0.44% (w/w, lactic acid) in 24 h. Yeasts used singly showed little activity within 12 h, but lowered the pH to 3.57-4.81 and increased the acidity to 0.11-0.21% in 24 h. Yeasts in co-culture with lactic acid bacteria (LAB) had a modest effect on the final acidity (P<0.05). The number of lactic acid bacteria and yeasts increased while the Enterobacteriaceae decreased with fermentation time. The pH was lowered and lactic acid produced significantly (P<0.05) fastest in natural togwa fermentation and in samples fermented by L. plantarum or L. plantarum in co-culture with I. orientalis. The content of fermentable sugars was reduced during fermentation. Most volatile flavour compounds were produced in samples from fermentation by P. pentosaceus and I. orientalis in co-culture with either L. plantarum or L. brevis.     

Aerobic industrial processing of Empeltre cv. natural black olives and product characterisation

The fermentation of natural black olives is currently carried out under anaerobic conditions. This work investigates the aerobic fermentation of this product in tanks containing 16 000 kg of Empeltre olives during two seasons. The microorganisms in brines were yeasts in all cases, whereas lactic acid bacteria growth was only observed in some tanks. Consequently, the pH during fermentation was in most cases higher than recommended 4.3 units. However, the Empeltre olive brines displayed bactericidal effect against Salmonella enterica, Sthapylococcus aureus, Escherichia coli and Listeria monocytogenes, with a 5 log population drop in one or 24 h depending on the brine age so that these olive brines are a harsh environment for the growth of these pathogens. It was found HyEDA as the major phenolic compound in both brine and olive pulp at the beginning of fermentation that slowly hydrolysed into hydroxytyrosol that reached a concentration up to 1500 mg kg⁻¹.     

Microbiological and physicochemical changes of naturally black olives fermented at different temperatures and NaCl levels in the brines

The effect of different temperatures (25°C, 18°C and ambient temperature) and NaCl levels in brines (4%, 6% and 8%) on the microbiological and physicochemical characteristics of naturally black olives of Conservolea variety was studied for up to 190 days. Fermentation was carried out according to the traditional anaerobic method. The initial microflora consisted of Gram-negative bacteria, lactic acid bacteria and yeasts. Inhibition of Gram-negative bacteria was evident in all fermentations. The prevailing micro-organisms were lactic acid bacteria and yeasts, the association of which was dependent on the conditions of fermentation. At 25°C and 18°C in brines containing 4% and 6% NaCl, the growth of lactic acid bacteria was favoured resulting in a lactic acid fermentation, as indicated by the high free acidity levels and low pH values in the brines. On the contrary, 8% NaCl concentration affected the growth of lactic acid bacteria and enhanced the activity of fermentative yeasts, producing a final product with lower free acidity and higher pH value. At ambient temperature, the counts of lactic acid bacteria followed the fluctuation of temperature regardless of salt concentration, while yeasts did not seem to be affected. The lactic acid bacteria identified belonged to the species Lactobacillus mesenteroides, Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus pentosus. The best conditions for fermentation were at 25°C and 6% NaCl, developing free acidity of 142 mM (1·28% w/v) lactic acid and pH value of 3·8. After 5 months of brining, olives fermented at 25°C were judged by panelists as being debittered and ready to eat. No off-odour development was detected in any case due to anomalous fermentation. The HPLC analysis revealed that citric, malic, tartaric, succinic, lactic and acetic were among the end products of fermentation.     

EFFECT OF THE USE OF DIFFERENT LACTIC STARTERS ON THE MICROBIOLOGICAL AND PHYSICOCHEMICAL CHARACTERISTICS OF NATURALLY BLACK TABLE OLIVES OF GEMLIK CULTIVAR

The effect of different lactic acid bacteria cultures on the physicochemical and microbiological characteristics of brined black olives of Gemlik cultivar at low fermentation temperature was studied. Fermentation was carried out according to the traditional Gemlik method with modifications like low salt concentration and lactic starter addition. The brines with 7% salt concentration were inoculated with lactic acid bacteria ( Lactobacillus brevis, Leuconostoc cremoris and L. paramesenteroides ), which were previously isolated from olive fruits at low temperatures and a commercial strain of Lb. plantarum. Fermentation procedures were carried out at controlled temperatures (between 10–12C). Lactic acid bacteria survival was accompanied by yeast development, no Pseudomonas and Enterobacter species were detected in all treatments during fermentation. The highest total titratable acidity, lowest pH and least yeast growth were determined at the brines and fermentation products, which were inoculated with L. cremoris.

PRACTICAL APPLICATIONS

The use of suitable starter cultures is necessary to improve the microbiological control of the naturally black table olive process, help to standardize the fermentation, increase the lactic acid yield and accordingly provide the production of olives with high quality. The requirements mentioned for starter cultures include a rapid and predominant growth, homofermentative metabolism, tolerance to salt, acid and polyphenols, and few growth factor requirements. Especially at the regions where olives were picked later when environmental temperatures are lower, the use of a starter culture that has the ability to grow at low temperatures may be necessary. Use of such starter cultures may help to increase acidification, to control some types of spoilage and to shorten the fermentation process.     

Fermentation profiles of Manzanilla-Aloreña cracked green table olives in different chloride salt mixtures

NaCl plays an important role in table olive processing affecting the flavour and microbiological stability of the final product. However, consumers demand foods low in sodium, which makes necessary to decrease levels of this mineral in fruits. In this work, the effects of diverse mixtures of NaCl, CaCl₂ and KCl on the fermentation profiles of cracked directly brined Manzanilla-Aloreña olives, were studied by means of response surface methodology based in a simplex lattice mixture design with constrains. All salt combinations led to lactic acid processes. The growth of Enterobacteriaceae populations was always limited and partially inhibited by the presence of CaCl₂. Only time to reach half maximum populations and decline rates of yeasts, which were higher as concentrations of NaCl or KCl increased, were affected, and correspondingly modelled, as a function of salt mixtures. However, lactic acid bacteria growth parameters could not be related to initial environmental conditions. They had a longer lag phase, slower growth and higher population levels than yeasts. Overall, the presence of CaCl₂ led to a slower Enterobacteriaceae and lactic acid bacteria growth than the traditional NaCl brine but to higher yeast activity. The presence of CaCl₂ in the fermentation brines also led to higher water activity, lower pH and combined acidity as well as a faster acidification while NaCl and KCl had fairly similar behaviours. Apparently, NaCl may be substituted in diverse proportions with KCl or CaCl₂ without substantially disturbing water activity or the usual fermentation profiles while producing olives with lower salt content.     

Green olive fermentation using spontaneous and <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> cultures

The aim of this work was to evaluate the performance of spontaneous and Lactobacillus cultures in Spanish style fermentation of olive fruits. A fermentation with Lactobacillus plantarum ATCC 8014 was carried out for comparison. Fermentation was performed at room temperature during 120 days in two different concentrations of NaCl (2.4–13.6 % w/v) and sucrose (0–0.82 % w/v) in the brines. The pH, chlorides, lactic acid, reducing sugar and lactic bacteria in selective medium were investigated during the olive fermentation. After 120 days of fermentation, the formulation with 12 % NaCl in the brine hampered the growth of lactic bacteria, avoiding the consumption of reducing sugars. However, low salt concentrations (≤4 %) promoted a decrease in pH, an increase of the lactic acid and the growth of lactic bacteria, providing best environmentally suitable for the fermentation process. Whereas using concentrations of 12 % NaCl and 0.7 % sucrose showed better chemical conditions, ensuring the safety of the product produced. Multivariate analysis showed that the olives with both cultures were in close relation to lactic acid and reducing sugar and different from lactic bacteria.     

Biofilm formation on abiotic and biotic surfaces during Spanish style green table olive fermentation

In this work, the establishment of polymicrobial communities on the surfaces which come into contact with the brine during Spanish style Gordal cv. green olive fermentation when subjected to spontaneous or controlled processes (inoculated with Lactobacillus pentosus LPCO10 or 128/2) was studied. Scanning electron microscopy showed that L. pentosus and yeast populations were able to form mixed biofilms throughout the fermentation process on both abiotic (glass slide) and biotic (olive skin) surfaces. The biofilm architectures in both supports were completely different: on the glass slides only aggregates of L. pentosus and yeasts without any polymeric matrix surrounding them were found while on the skin of the fruits, true mature biofilms were observed. During fermentation, the lactic acid bacteria (LAB) population on the olives remained similar while that of yeasts increased progressively to reach similar levels at the end of the process (8-9 log CFU/cm(2)). Molecular analysis showed that different populations of L. pentosus and yeasts were the only microbial members of the biofilm formed during fermentation, regardless of inoculation. Hence, the green olive surface provides an appropriate environmental condition for the suitable development and formation of complex biofilms during controlled or natural table olive processing.     

Influence of fruit ripeness and salt concentration on the microbial processing of Arbequina table olives

Arbequina table olives are processed as “naturally green olives”, they are directly placed in brine and fermentation starts spontaneously. Olives are harvested just before they change to ‘turning colour’. Different salt concentrations are used depending on the producer. The aim of the study was to evaluate how (i) the ripeness of the olive when it is harvested and (ii) the salt concentration of the brine influence the different microorganism populations in brine during the fermentation of Arbequina table olives.The results showed that the Enterobacteriaceae population lasted longer in black and turning colour olives than in green olives, whereas the growth of lactic acid bacteria was delayed in green olives. A higher salt concentration favoured the elimination of Enterobacteriaceae and hindered yeast growth. The main yeast species identified were Pichia anomala, Candida sorbosa and Candida boidinii, while Lactobacillus plantarum was the only lactic acid bacteria species involved in the process. In a sensory test, panellists preferred green olives and were not able to tell the laboratory-scale processed olives from a commercial sample, nor could they distinguish green olives from different brines.     

Microbiological profiles, pH, and titratable acidity of chorizo and salchichón (two Spanish dry fermented sausages) manufactured with ostrich, deer, or pork meat

Microbial counts, pH, and titratable acidity were determined in 102 Spanish dry fermented sausages (chorizo and salchichón) made with ostrich, deer, or pork meat. Average microbial counts (log CFU per gram) varied from 5.46 +/- 0.24 to 8.25 +/- 0.80 (total viable counts), from 4.79 +/- 0.36 to 7.99 +/- 0.20 (psychrotrophs), from 0.00 +/- 0.00 to 0.99 +/- 1.10 (undetectable values were assumed to be zero) (Enterobacteriaceae), from 0.00 +/- 0.00 to 4.27 +/- 1.47 (enterococci), from 5.15 +/- 1.15 to 8.46 +/- 0.49 (lactic acid bacteria), from 3.08 +/- 0.44 to 6.59 +/- 1.76 (Micrococcaceae), from 2.27 +/- 1.53 to 5.11 +/- 1.81 (molds and yeasts), from 0.00 +/- 0.00 to 2.25 +/- 0.81 (pseudomonads), and from 0.00 +/- 0.00 to 2.78 +/- 0.46 (Brochothrix thermosphacta). Average pH and titratable acidity varied from 5.07 +/- 0.25 to 5.63 +/- 0.51 (pH units) and from 0.30 +/- 0.01 to 0.86 +/- 0.19 (% lactic acid). Both type of sausage (P < 0.05) and species of meat (P < 0.001) influenced microbial counts. Salchich6n samples showed lower average values than chorizo samples for most microbial groups (significant for Enterobacteriaceae, lactic acid bacteria, and B. thermosphacta) and titratable acidity. Sausages made from pork showed the highest microbial loads for total viable counts, psychrotrophs, Enterobacteriaceae, enterococci, lactic acid bacteria, and yeasts and molds. Higher counts were observed only for pseudomonads in ostrich sausages. B. thermosphacta levels were similar for all species of meat. The highest average pH value was observed in sausages made from ostrich meat, and the lowest titratable acidity level was found in pork sausages.     

Physicochemical, microbiological, and organoleptic profiles of Greek table olives from retail outlets

The physicochemical, microbiological, and organoleptic profile of different commercial table olive products from retail outlets was studied. Average pH values were 4.00, 3.96, and 4.31 for Spanish-style green, naturally black, and dry-salted olives, respectively, while salt content was 6.21, 7.34, and 8.00% for the same commercial products. Mean values for titratable acidity were 0.53 and 0.63% (wt/vol) for green and naturally black olives. In general, mean values for pH, titratable acidity, and salt content were in accordance with the requirements established by the International Olive Oil Council (IOOC) for the trade of table olives, although considerable variation was observed within individual olive samples. Salt content of dry-salted olives did not meet the minimum limit of 10% established by the IOOC. The dominant microbiota consisted of lactic acid bacteria and yeasts. Their population was less than 10(9) CFU ml(-1), as stipulated by the IOOC standard for fermented olives held in bulk in a covering liquid. These microorganisms come from the natural microbiota found in spontaneous fermentations and impose no risk to human health. No enterobacteria, pseudomonads, Bacillus cereus, or Clostridium perfringens were detected in any of the samples given the physicochemical characteristics found. The organoleptic profile varied greatly according to processing style and commercial preparation. Green olives had more uniform sensory characteristics than naturally black and dry-salted olives. The most important attributes that influenced the judgment of the panelists were salt content and crispness of the olives.     

Diversity of bacterial population of table olives assessed by PCR-DGGE analysis

Nocellara Etnea and Geracese table olives are produced according to traditional process, in which lactic acid bacteria (LAB) and yeasts are the dominant microorganisms. With the aim to evaluate the effect of selected starter cultures on dynamics of bacterial population during fermentation and on growth/survival of Listeria spp. artificially inoculated into the olive brine, a polyphasic approach based on the combination of culturing and PCR-DGGE analysis was applied. Plating results showed a different concentration of the major bacterial groups considered among cultivars and the beneficial effect of LAB starters, which clearly inhibited Enterobacteriaceae. Moreover, results indicated that the brine conditions applied did not support the growth/survival of Listeria monocytogenes strain, artificially inoculated, highlighting the importance of selecting right fermentation parameters for assuring microbiological safety of the final products. Comparison of DGGE profile of Nocellara Etnea and Geracese table olives, displayed a great difference among cultivars, revealing a wide biodiversity within Lactobacillus population during Geracese olives fermentation. Based on cloning and sequencing of the most dominant amplicons, the presence, among others, of Lactobacillus paracollinoides and Lactobacillus coryniformis in Geracese table olives was revealed in table olives for the first time.     

The microflora of fermented nixtamalized corn

Nixtamalization is a traditional process that improves the nutritional quality of corn. To provide a means of utilizing the nutritional benefits of nixtamalized corn and improve product acceptability, lactic acid fermentation was applied. The objective of the study was to study the microbial profile and establish the important lactobacilli of fermenting nixtamalized corn dough. Two batches of cleaned whole corn were subjected to the process of nixtamalization, using two concentrations of lime (0.5 or 1.0%), milled, made into a dough (50% moisture) and fermented spontaneously for 72 h. A control sample was prepared without alkaline treatment. pH and titratable acidity of the dough were measured. Aerobic mesophiles, lactic acid bacteria, yeasts and molds were enumerated on Plate Count Agar (PCA), deMan, Rogossa and Sharpe (MRS) Agar and Malt Extract Agar (MEA), respectively. The identity of lactobacilli present was established at the species level using API 50 CHL. The pH of all the fermenting systems decreased with fermentation time with concomitant increase in titratable acidity. Lactic acid bacteria in numbers of 1.6 x 10(9), 2.3 x 10(9) and 1.8 x 10(9) cfu/g, respectively yeasts and molds, and numbers of 8.0 x 10(7), 5.0 x 10(5) and 1.7 x 10(5) cfu/g, respectively were observed in the control and the two nixtamalized (0.5% and 1.0% lime) samples after 48 h of fermentation. Lactobacilli identified in the fermenting nixtamalized corn dough were Lactobacillus plantarum, Lactobacillus fermentum and Lactobacillus cellobiosus as well as Pediococcus spp. The study demonstrates that nixtamalized corn though alkaline in nature can be subjected to spontaneous fermentation to produce a sour product.     

食盐与大蒜发酵泡菜品质的对比分析

以大白菜为原料,研究不同浓度的食盐与不同质量分数的大蒜在发酵泡菜中生化指标（pH,可滴定酸,亚硝酸盐）,微生物指标（细菌总量,乳酸菌,肠杆菌）,感官评价（颜色,香气,滋味,质地）的相似点与差异性。结果表明：6种泡菜第10d后都具有较高的安全性,大蒜与食盐具有相似的抑菌效果,5％大蒜与4％的食盐在发酵的过程中各种指标变化相当,其中5％大蒜的感官评价最高。     

新疆酸白菜发酵的研究

通过对低温自然发酵中的酸白菜进行定期取样,分析了乳酸菌、大肠杆菌、酵母菌及细菌总数的变化,同时测定发酵过程中酸白菜酸度和脆度指标.结果表明,发酵初期人肠杆菌和杂菌为优势菌群,酸度为0.31%,脆度为10.06mJ;发酵中期乳酸菌成为优势菌群,其次为酵母菌,酸度为0.66%,脆度为15.01mJ;发酵末期大肠杆菌被抑制,乳酸菌和酵母菌减少,但乳酸菌仍然是优势菌群,酸度为1.27%,脆度为36.47mJ.酸度0.66%及脆度15.01mJ时,酸白菜口感风味最佳.     

Olive Fermentation and Processing: Scientific and Technological Challenges

ABSTRACT: The 3 main commercial table olive preparations are the Spanish-style green olives, the Greek-style naturally black olives, and the Californian-style black ripe olives. In all cases, fruits undergo fermentation in brine solution, which preserves them and increases palatability. Lactic acid bacteria dominate in brines of green olives, while mainly fermentative yeasts are found in brines of black ones. The fermentation is spontaneous and begins as soon as olives are put into brine. Research on table olives has been going on for 100 years, but many questions remain. Previous work has focused on the efficient utilization of starter cultures in order to control the fermentation, to guarantee the absence of spoilage, and to govern the relationship between olive flavor and microorganisms. Nowadays, there is concern over environmental problems that the fermentation solutions represent, in particular their high NaCl content. Fermentation or simply storing olives in water without salt presents some problems. The high concentration of sodium benzoate used for storing black ripe olives by the American industries is not advisable for European processes due to the residual amount of preservative in the final product. Fermentation of green olive wash waters, in order to obtain valuable products, is being pursued, but polymeric inhibitors are problematic and undesirable microorganisms grow. The consumption of organic foods is increasing and black olives fit the definition since they are processed without chemical treatment. However, the hydrolysis of the bitter compound oleuropein, either by microorganisms or acids, needs to be studied.