I was just scanning other blogs and this one from Passion for Savings caught my eye:
How to Make Berries Last Longer!
I haven't tried it myself, but it sounds like it would be worth a try (small batch first to make sure that I Really can not taste the vinegar) :)
All you need is White Vinegar and Water and a Large Bowl.
Combine 4 Cups Water with 1/2 Cup Vinegar in a Bowl
Place Berries in the Vinegar/Water Mixture to kill the bacteria on
the Berries and then remove and lay on a towel to dry. This helps the
berries last so much longer! My kids go through a container of
Strawberries a day sometimes so I will often buy 4-5 containers and this
helps those last few containers last and look fresh even after several
Tip: As long as you let the Berries Dry Completely you won’t taste
the Vinegar, this evaporates into the air and there is no flavor left