It happens to me all the time… I bring soft berries like strawberries home, rinse and chill them, and by the next day half are moldy, inedible and very unappealing!
The NY Times recently carried a story about keeping soft berries, grapes and stone fruit longer; it’s called Thermotherapy. The idea is almost the same as what you do before freezing vegetables… blanch them.
In this case though, it’s only a quick dip in water between 113ºF and 145ºF instead of the method of blanching vegetables a couple of minutes in boiling water. Both techniques do the same thing: reduce mold spores on the skin surface.
I would have thought the hot water dip would harm the berries. However, ‘Reason’ tells me berries have to withstand the hot temperatures of sunshine in the field, so why not a quick hot bath, followed by icy cold immersion to stop any cooking?
When the author experimented with several batches of strawberries, they kept best and longest dipped in water heated to 125º for 30 seconds. Her methods evolved from several agriculture research articles, and the process really sounds like something I will use next year when soft fruits are ready again. Except of course, my home-grown berries, which get eaten or processed some way almost immediately.
You’ll need a good calibrated thermometer, and a good timer that counts seconds. Read the story (and how to DIY) here.