Viability of commercial cucumber fermentation without nitrogen or air purging

It was understood that microbial activity during fermentation, cucumber tissue respiration, as well as the pressure in the fruits and fermentation tanks, ambient temperature and cover brine composition, impact the levels of dissolved CO2 in the system. Although the biological conversion of oxygen to CO2 reduces the cucumbers internal gas pressure, the dissipation of the gas from the tissue is reduced by brining. Once the gas accumulates in the cucumber tissue in concentrations high enough to displace it, the irreversible formation of hollow cavities or bloaters occurs. Residual CO2 is produced by acid-preserved cucumbers, presumably by tissue respiration, which results in the absence of bloating. Thus, microbial activity seems to contribute most of the CO2 needed for cucumbers to bloat. It is speculated that colonization of the internal cucumber tissue by indigenous microbes, in particular aerobic gram-negative bacteria, results in the localized production of CO2 causing bloating defect early in the fermentation. It is concluded that effective manipulation of the microbiota, reduction of dissolved oxygen levels and the use of adequately selected starter cultures may enable cucumber fermentations of acceptable quality without purging.