Formation of gas pocket defect in Spanish-style green olives by the halophile Celerinatantimonas sp

Abstract

Gas pocket defect causes substantial losses every season to Spanish-style green table olive processors. This defect has been thought to be caused by microorganisms that are able to produce gaseous compounds that break the flesh and/or the epidermis of olive fruits. This study was focused on the search for the microorganism actually responsible for this spoilage. Metataxonomy analysis of industrial spoiled brines demonstrated the presence of Celerinatantimonas as the most probable source leading to gas pocket formation. Several bacterial isolates were obtained from different industrial spoiled brines whose 16S rRNA sequence closest homologue was Celerinatantimonas diazotrophica (94–96% similarity). Vigorous gas production (H2 and CO2) by these isolates in broth cultures was confirmed. Inoculation of microbial pellets from one of these spoiled brines did indeed provoke gas pocket formation in fresh batches of Spanish-style green olives. Although the species C. diazotrophica has been previously reported in metataxonomy studies in samples of table olives, this is the first time that it was isolated from fermenting table olive samples. In addition, this is the first report that associates this species to the gas pocket defect in table olives. Thus, inoculation with one of the wild-type isolates identified as C. diazotrophica in table olive brines confirmed the involvement of this microorganism in the formation of the gas pocket defect in Spanish-style green olives.