Farm-to-consumer quantitative microbial risk assessment model for Listeria monocytogenes on fresh-cut cantaloupe.

Cantaloupe contamination with the foodborne pathogen Listeria monocytogenes (LM) may occur along the supply chain. We developed a quantitative microbial risk assessment (QMRA) model for LM on cantaloupe along the fresh-cut supply chain and evaluated potential risk reduction strategies. The developed model starts at harvest and includes conditions during transportation from field to intermediate facility (packinghouse or cooling facility), handling at the intermediate facility, transportation to the fresh-cut facility, storage pre-processing at the fresh-cut facility, processing and handling at the fresh-cut facility, as well as conditions during distribution, retail, transportation to home, and home storage. The model was simulated to (i) provide an estimate of LM concentration in a single serving (134 g) and (ii) estimate annual illnesses and deaths in the United States attributed to LM contaminated fresh-cut cantaloupe. The baseline model predicted the median risk of listeriosis per serving in general and susceptible populations was 1.4 x 10^-12 and 6.4 x 10^-11, respectively. The median (5^th, 95^th percentiles) predicted number of illnesses and deaths annually attributed to fresh-cut cantaloupe were 0 (0, 1070) and 0 (0, 264), respectively. Time and temperature conditions post-packaging, and the initial number of LM at harvest had the greatest impacts on LM per contaminated serving and the number of annual illnesses; the initial LM levels at harvest and cross-contamination parameters at the fresh-cut facility had the greatest impacts on prevalence of contaminated servings. Assessment of interventions demonstrated that reducing temperature and/or time conditions post-packaging can be an effective risk reduction strategy. Overall, the developed tool estimates the risk associated with the consumption of LM contaminated fresh-cut cantaloupe and facilitates the identification and assessment of potential risk reduction strategies across the supply chain.