US: Produce crops are safer 24 hours after rain, irrigation
Food Safety Magazine: New research published in Applied and Environmental Microbiology–a scientific journal–says that produce [spinach] farmers should wait until 24 hours after rain or irrigation to harvest their crops. The practice is said to protect consumers from foodborne illness.
After testing fields [of spinach] throughout New York state, researchers found that the presence of Listeria was 25 times greater just after an episode of rain or irrigation. When the researchers waited for 24 hours, traces of Listeria contamination decreased dramatically.
As a result of these findings, the U.S. Food and Drug Administration has asked that farmers begin enforcing the 24 hour wait period before harvesting fresh produce after rain and irrigation.