Alcohol dehydrogenase activity in Lactococcus chungangensis: Application in cream cheese to moderate alcohol uptake

Many human gastrointestinal facultative anaerobic and aerobic bacteria possess alcohol dehydrogenase (ADH) activity and are therefore capable of oxidizing ethanol to acetaldehyde. However, the ADH activity of Lactococcus spp., except Lactococcus lactis ssp. lactis, has not been widely determined, though they play an important role as the starter for most cheesemaking technologies. Cheese is a functional food recognized as an aid to digestion. In the current study, the ADH activity of Lactococcus chungangensis CAU 28T and 11 reference strains from the genus Lactococcus was determined. Only 5 strains, 3 of dairy origin, L. lactis ssp. lactis KCTC 3769T, L. lactis ssp. cremoris KCCM 40699T, and Lactococcus raffinolactis DSM 20443T, and 2 of nondairy origin, Lactococcus fujiensis NJ317T and Lactococcus chungangensis CAU 28T KCTC 13185T, showed ADH activity and possessed the ADH gene. All these strains were capable of making cheese, but the highest level of ADH activity was found in L. chungangensis, with 45.9 nmol/min per gram in tryptic soy broth and 65.8 nmol/min per gram in cream cheese. The extent that consumption of cheese, following imbibing alcohol, reduced alcohol uptake was observed by following the level of alcohol in the serum of mice. The results show a potential novel benefit of cheese as a dairy functional food.