Bacterial strains are provided that can be isolated from the microflora of lowbush blueberry (Vaccinium angustifolium), and that are capable of increasing the antioxidant content of their growth medium. The bacteria can be used, for example, to increase the antioxidant content of various foodstuffs, as probiotics or as additives to animal feed. Antioxidant-enriched compositions produced by fermentation processes utilising the bacteria are also provided. The antioxidant-enriched compositions can be used in the preparation of cosmetics and nutritional supplements. The antioxidant-enriched compositions also have therapeutic applications.