Media types looking for a sound bite on Listeria in cantaloupes are pulling their hair out tonight.
You couldn’t ask for a more complicated scenario. Advice like “wash your hands” or “cook your foods” or “don’t cross contaminate” is nearly worthless. Here are some troubling facts
Listeria monocytogenes:
- Psychrophilic, multiplication possible all the way to 29 degrees
- Ubiquitous, found in almost all environments, terrestrial and aquatic
- Found in feces of animals
- Most problematic in ready to eat foods
- Forms bio films on food prep surfaces that resist sanitizers, nearly impossible to remove once adhesion occurs
- Incubation period can be days to months
- Huge dose response curve, from 100 or less cells, to 1,000,000 or more
- High morbidity and mortality up to 50% of cases
- Some strains are pathogenic some are not
- Highly virulent strains may be emerging
- Targets immune-suppressed victims, fetuses, neonates, pregnant, those on immunosuppressive drugs, those with disorders of the liver, gut, blood
- Attaches to nervous tissues, systemic infections
Cantaloupes:
- Rough netted exterior traps contaminants
- The rind surfaces of these melons likely can support adhesion as well as colonization by many pathogenic bacteria
- Melon meat is highly conducive to bacterial multiplication, rich in nutrients and moisture just below the rind
- Keeps well under refrigeration
- When cut, surface pathogens are transferred into the meat
Combine the two and you have a marriage made in hell.