Capacity of Listeria monocytogenes Strains from the 2011 Cantaloupe Outbreak To Adhere, Survive, and Grow on Cantaloupe.
The 2011 listeriosis outbreak attributed to whole cantaloupe involved several genetically distinct strains of serotypes 1/2a and 1/2b that had not been previously reported in invasive listeriosis outbreaks. Here we investigated the potential of strains from the 2011 cantaloupe outbreak to adhere, survive, and grow on cantaloupe rind and flesh and in juice extracted from cantaloupe at different temperatures (4, 8, and 25°C). All strains were able to adhere and grow, with ∼10-fold increases after 7 days at 4 or 8°C and after 24 h at 25°C, with a propensity for more growth on rind than on flesh or in extract. No significant differences in growth potential were noted among the different strains or between them and unrelated strains from other listeriosis outbreaks involving celery, deli meats, or hot dogs. Similarly to the cantaloupe outbreak strains, these other strains exhibited greater propensity for growth on rind than on flesh or in extract. Rinsing of cantaloupe fragments in sterile water resulted in temporary reductions of the populations by 50- to 100-fold, suggesting the potential of such washing to reduce risk if the produce is promptly consumed. The absence of marked differences in adherence or growth between the cantaloupe outbreak strains and strains from other outbreaks highlights the need to further characterize the 2011 cantaloupe outbreak strains and elucidate potential biological attributes that contributed to their implication in the outbreak.
Departments of Food, Bioprocessing, and Nutrition Science, North Carolina State University, Raleigh, North Carolina 27695, USA; Faculty of Veterinary Medicine, University of Belgrade, 11000 Belgrade, Serbia.
Mira Rakic
MR
Martinez
Statistics, North Carolina State University, Raleigh, North Carolina 27695, USA.
Jason
J
Osborne
Departments of Food, Bioprocessing, and Nutrition Science, North Carolina State University, Raleigh, North Carolina 27695, USA.
Victor Oladimeji
VO
Jayeola
Faculty of Veterinary Medicine, University of Belgrade, 11000 Belgrade, Serbia.
Vera
V
Katic
Departments of Food, Bioprocessing, and Nutrition Science, North Carolina State University, Raleigh, North Carolina 27695, USA. skathar@ncsu.edu.
Sophia
S
Kathariou
D028463:Cucumis melo; D004196:Disease Outbreaks; D005516:Food Microbiology; D008089:Listeria monocytogenes; D008088:Listeriosis / Q000453:epidemiology