has component process has input has output Kefir kefir grains glucose metabolism during food fermentation kefir fermentation https://orcid.org/0000-0002-7114-7726 https://orcid.org/0000-0001-9446-7979 The set of reactions leading to the conversion of carbohydrates into organic acids, ethanol and CO2 by the enzymatic activity of kefir microbiota https://github.com/FrancescoVit fermentation ons milk