Do you take your juice to work with you? What do you store it in?
I do not normally take juice to work with me. It is preferably to drink it immediately because otherwise it will oxidize, taste funny and lose nutrients.
To get around this, I brought another juicer and I keep it permanently at work.
Then I either take veggies with me to work (or sometimes get them delivered) and keep them in the fridge until I want to make a juice.
Otherwise if this does not suit, I suggest using a glass Mason jar with an air tight seal-able lid. You can also buy esky / freezer / cooler / bags to keep the jar of juice cold, if taking with you in summer.