US Patent 7553638 None

Food containing γ-glutamylcysteine or cysteine is produced by culturing Candida utilis containing 1% by weight or more of γ-glutamylcysteine per dry cells in logarithmic growth phase when cultured in a minimal medium, for example, Candida utilis in which a gene encoding glutathione synthetase is modified so that intracellular glutathione synthetase activity is reduced, under a suitable condition and mixing the obtained culture or a fraction thereof or the culture or a fraction thereof subjected to heat treatment with a raw material of food or drink to process food or drink.