Munching on fresh cantaloupe this morning made me check in on the status of the Salmonella Litchfield outbreak that has sickened 50 across the United States over the last months. Unfortunately, outbreaks tied to cantaloupe have been a far to frequent occurrence. There have been several articles on what consumers can and can not do to protect themselves. I wondered what growers and shippers might be doing. I found this interesting article and great pictures – from 2005. Guess we need to do a bit more?
Scientists Aim for Cleaner Cantaloupe
Simply washing fresh fruits and vegetables may only be marginally effective at removing microbial contaminants, so scientists are investigating new techniques for better processing produce.
Bacteria quickly attach to the surface of fruits and vegetables and form biofilms, a mass of microbes that attach to a surface and to each other by complex sugars. Scientists believe that biofilm coatings may protect bacterial cells from exposure to antimicrobial compounds used to sanitize produce.
Salmonella bacteria are often responsible for produce-related outbreaks of foodborne illness. They’re especially tricky to remove from cantaloupe because they attach to inaccessible sites and form biolfim on cantaloupe rind surface, allowing the bacteria to avoid contact with sanitizing solutions. Surviving Salmonella cells can be transferred from the surface of the melon to the internal tissues during cutting prior to consumption.
Now, researchers at the USDA’s Agricultural Research Service have gained new insight into Salmonella biofilm formation on various surfaces. They have discovered that to form on plastic or stainless steel, the bacteria must produce hair-like structures–called fimbriae–and cellulose to help the cells to attach and colonize the surface.
In cantaloupe, Salmonella cells attach to the rind and rapidly begin developing biofilm by growing and excreting sugars. This discovery helps explain how Salmonella survives harsh sanitizing environments and could help lead to better sanitization techniques.