Contribution of Leuconostocaceae to CO2-mediated bloater defect in cucumber fermentation.

Fermented cucumber bloater defect, caused by the accumulation of microbiologically produced carbon dioxide (CO2), creates significant economic losses for the pickling industry. The ability of Leuconostocaceae, indigenous to cucumber, to grow and produce CO2 during a fermentation and cause bloater defect was evaluated. Leuconostocaceae grew and produced over 40% CO2 in cucumber juice medium, used as a model for cucumber fermentation. The inoculation of Leuconostocaceae to 5 Log CFU/g in cucumber fermentations brined with 25 mM calcium chloride and 6 mM potassium sorbate resulted in no significant differences in bloater defect, colony counts from MRS and VRBG agar plates or the fermentation biochemistry; suggesting an inability of the inoculated bacterial species to prevail in the bioconversion. Acidified cucumbers were subjected to a fermentation inoculated with a Leuconostoc lactis starter culture after raising the pH to 5.9 ± 0.4. CO2 was produced in the acidified cucumber fermentations to 13.6 ± 3.5% yielding a bloater index of 21.3 ± 6.4; while 8.6 ± 0.8% CO2 and a bloater index of 5.2 ± 5.9 were observed in the non-inoculated control jars. Together the data collected demonstrate that Leuconostocaceae can produce enough CO2 to contribute to bloater defect, if not outcompeted by the leading lactic acid bacteria in a cucumber fermentation. Published by Elsevier Ltd.