I've tried this and it actually works! When you get your berries home, prepare a mixture of one part white or apple cider vinegar and 10 parts water. Dump the berries into the mixture and swirl around. Drain and rinse, however the mixture is so diluted you can't taste the vinegar. I rinse the original plastic container and place a paper towel in the bottom. Pop it into the fridge.
The vinegar kills any spores and other bacteria. Raspberries will last a week or more and I've had strawberries last as long as two weeks without getting moldy or soft. Another strawberry tip is to remove the green from the top and push a drinking straw through to the end to remove the core.
Source: My friend Cheri.
By Connie from Las Vegas, NV