Juice does stay fresh for about 24-36 hours if it is kept in cold climate, the loss of the nutrients come with time. Juice is better consumed right after you make it because the more time you take to consume it the less nutrient value it will have. You should consume the juice right away to get the full value of your juice. But for your fellow co-workers they are probably consuming it more for taste and some nutrients, it is safe for them to drink within the recommended time.