Preventing postharvest decay after rain

The past two months has seen the usual extended periods of cool evening condensation but also some decent rainfall in many parts of California. Between the two, a spike in calls regarding postharvest decay of bell pepper and fresh market tomato has followed.

This used to be a common, almost traditional, fall season event with late crops but with many years of drought it hasn’t come up as often. Much of the potential for control revolves around postharvest dump and flume management to minimize cross-contamination but more often infection is field and harvest initiated and even the best antimicrobial water treatments cannot prevent decay in transit.

Packing wet bell peppers is not advisable but is especially risky with these rainy conditions.

One option taken by shippers has always been a switch from ‘wet-dump’ to ‘dry-dump’ to avoid cross-contamination and internalization into the cap or stem-end under the calyx, often partially lifted from the fruit wall during harvest.  This can reduce decay but, in these days of greater attention to food safety, it is important to pay attention to Listeria management when a packing line is modified or McGyvered (our new favorite description from a popular television show). A case example from the past is included on page 35 of the United Fresh Produce Association Guidance on Environmental Monitoring and Control of Listeria for the Fresh Produce Industry available on the University of California, Davis, website here.

Source: UC Davis Postharvest Technology Center