The invention relates to the novel use of ergothioneine and preferably, L ergothioneine, as a nutritional additive and preservative in foods, medicines, and/or beverages. According to the invention, the powerful antioxidant ergothioneine was found to be very stable over time in and to have no deleterious effects on taste or consistency of food and beverages even when stored, over a period of several years. In a preferred embodiment, ergothioneine may be used as a replacement for all or part of the antimicrobial/preservative sulfur dioxide or other sulfites traditionally used in the wine making process.