Pure Culture Fermentation of Green Olives1

Abstract

Pure culture fermentation of green olives. Appl. Microbiol. 14: 1027-1041. 1966.-The method previously developed by us for the pure-culture fermentation of brined cucumbers and other vegetables has been applied successfully to Manzanillo variety olives. Field-run grade fruit was processed first by conventional procedures to remove most of the bitterness. Then the relative abilities of Lactobacillus plantarum, L. brevis, Pediococcus cerevisiae, and Leuconostoc mesenteroides to become established and produce acid in both heat-shocked (74 C for 3 min) and unheated olives, brined at 4.7 to 5.9% NaCl (w/v basis), were evaluated. The heat-shock treatment not only proved effective in ridding the fruit of naturally occurring, interfering, and competitive microbial groups prior to brining and inoculation. but also made the olives highly fermentable with respect to growth and acid production by the introduced culture, particularly L. plantarum. Of the four species used as inocula, L. plantarum was by far the most vigorous in fermentation ability. It consistently produced the highest levels of brine acidity (1.0 to 1.2% calculated as lactic acid) and the lowestpH values (3.8 to 3.9) during the fermentation of heat-shocked olives. Also, L. plantarum completely dominated fermentations when used in two-species (with P. cerevisiae) and three-species (with P. cerevisiae and L. brevis) combinations as inocula. In contrast, when L. plantarum was inoculated into the brines of unheated olives it failed to become properly established; the same was true for the other species tested, but even to a more pronounced degree. L. brevis was the only species used that failed to develop in brines of both heat-shocked and unheated olives. Modification of the curing brine by the addition of lactic acid at the outset, either with or without dextrose, led to a much earlier onset of fermentation with accompanying acid development, as compared to treatments with dextrose alone or nonadditive controls. Reasons for the marked improvement of the fermentability of Manzanillo olives receiving the prebrining heat-shock treatment are discussed. Vaughn (28) called attention to the similarity of the predominating microbial changes occurring during the brine fermentation of the Sevillano variety of green olives to those of cucumbers fermented in brine with a low salt concentration (ca. 5% by weight). Species of bacteria in three genera-Aerobacter, Leuconostoc, and Lactobacillus-were considered common to both types

Vapor Analysis of Fermented Spanish‐type Green Olives by Gas Chromatography

“…The sample which failed to ferment did not receive 2.5 ml Olive samples inoculated with L. Plantarum and P. cerevisiae resulted in successful fermentations as determined by the abundant growth of these microorganisms with resulting pH and acidity values typical of a desirabh product (Table 1). L. mesenteroides was less dependable as the fermenting bacterium as was reported by Etchells et al (1966). of lactic acid prior to inoculation as did the other samples reported in Table 1.…”

“…The pure-culture fermented Spanish-type green olives (Manzanillo variety) examined in this study were samples from a previous study (Etchells et al, 1966). The processing of these samples involved lye treatment to remove bitterness, removal of the lye by leaching in water, heat-shocking the olives at 74°C for 3 min in a water bath, followed by packing into 0.5gal glass jars with a pasteurized and cooled 40" salometer brine ( 10.6% NaCl).…”

“…The jars scheduled for inoculation received 8 ml of a 30 hr culture of the designated species of lactic acid bacterium which had been grown at 32°C in Trypticase Sugar Broth (BBL). After incubating the samples at 21-24°C for 7.5 months, the olives were evaluated as to flavor and other organoleptic and physical qualities as described by Etchells et al (1966). Assays of the brines for titratable acidity, pH, and transmittance, and microscopic examination of brines were determined according to Etchells et al (1964).…”

“…Recent efforts have been made to control more closely the quality of such products. This is done by regulating the microbial flora with the addition of pure cultures of lactic acid bacteria to heat-shocked cucumbers and olives (Etchells et al, 1964(Etchells et al, , 1966.…”

Texture of Table Olives and Pimentos

“…Marquez Gonzalez et al (1975) and Etchells et al (1966Etchells et al ( , 1975 applied the FFL Penetrometer to studying the effect on texture of different factors such as fruit size, variety and treatments. et al (1973) undertook a comparative texture study on processed olives of 4 varieties (the 3 mentioned above plus Pic0 Limbn) with 2 devices, the Shear Press and the FFL Penetrometer.…”