Study on Microbial Control of Food Using Carbon Dioxide

Abstract

Carbon dioxide (CO₂) is a safe and inexpensive gas that is used as a food additive. In this study, microbial control by pressurized CO₂ was examined. Pre-solubilization of CO₂ at 1MPa at 4°Cmarkedly decreased the heat tolerance of vegetative bacterial cells through acidification of intracellular pH. Further, a 5- to 6-log reduction in vegetative bacterial cells was observed after incubation at around 60°Cfor 1 min. The inactivation effect of pressurized CO₂ on bacterial spores was increased in the presence of monoglycerol monocaprate (MC10; 0.05% w/v). The pressurized CO₂ accelerated MC10 adhesion to the spores as well as the release of dipicolinic acid from the spores, considerably decreasing physiological germination and/or heat resistance. When pressurized CO₂ was applied during the fermentation of sardine fish sauce, the salt concentration required for the inhibition of undesirable microorganism growth was reduced from 20% to 10%. In addition, the reduction of salt in fish sauce improved its nutritional and sensory qualities compared to that produced by the conventional method. These findings support the practical application of CO₂ for microbial control in foods and contribute to the development of improved food processing methods.