Question
I would like to know how listeria get into cantaloupe melons, as it has done in America?  It seems a bit frightening that organisms can pass into fruit or vegetables.  Would appreciate your answer.  Thank you Diana Lake

Answer
Diana,

Officials in the United States are investigating the exact source of the Listeria contamination.  The exact cause is not yet known.  The most likely source of contamination is that the bacteria was present on the rind and when consumers cut into the melon, they transferred the bacteria from the surface to the internal flesh.  In many cases, contamination can be prevented by thoroughly washing the melon prior to cutting it.  The following publication from the Univ. of California provides tips for handling and preparing melons:
http://ucanr.org/freepubs/docs/8095.pdf

You may also want to visit the CDC's webpage on Listeriosis which shows the latest updates on the outbreak.  I expect that they will continue to update this website as more information is uncovered.
http://www.cdc.gov/listeria/index.html