Characteristics of Lactic Acid Bacteria from Commercial Cucumber Fermentations.

In commercial practice cucumbers are brined in wooden vats ranging in capacity from about 100 to 1,200 bushels. The vats, after being filled with green cucumbers, are fitted with false heads, and salt brine of a given concentration is added to a level a few inches above the head. Next, dry salt is added on the false head of the vat to maintain the initial concentration, which otherwise would become diluted by the water from the cucumbers. The initial brine strength used ordinarily ranges from about 8 to 10 per cent, depending upon the individual plant concerned. In most instances the brine concentration is gradually raised so that a holding strength of about 16 to 18 per cent is reached after about 6 weeks. Under these conditions an active acid fermentation resulting from the growth of salt-tolerant, acid-forming bacteria usually begins within a day or so after the cucumbers are brined and may continue for about 6 weeks. The preserving effect of the brine is due chiefly to the combined action of the salt and the developed acidity. The role of the acid-forming bacteria in commercial cucumber fermentations, from the standpoint of populations occurring at various brine strengths and their relation to the principal chemical changes taking place in the brines, is probably better understood than the identity of the organisms concerned. The present study was undertaken in an effort to obtain more specific information on the nature of the predominating lactic acid bacteria involved during the fermentation of salt-stock cucumbers, under conditions typical of the industry.