Vitamin K2 is essential for maintaining human health. It is required for blood coagulation and contributes to cardiovascular and bone health. Bacteria are the natural producers of vitamin K2 and known producers of vitamin K2 such as Lactococcus lactis are key players in the production of fermented foods. This fact offers opportunities to enhance vitamin K2 levels in food. In this study, Liu optimized the production of vitamin K2 in L. lactis and she demonstrated efficient delivery of vitamin K2 to human bone cells by nano-sized bacterial extracellular membrane vesicles (EVs). L. lactis was found to produce EVs that naturally contain membrane-imbedded vitamin K2, thereby improving the solubility of this vitamin, making it easier to be utilized by the human cells to achieve desired function. Just like small gift packages, L. lactis secretes vitamin K2 via EVs and delivers thus potential health benefits to humans.