title: Quantitative Microbial Risk Assessment for Escherichia coli O157:H7 in Fresh-Cut Lettuce.
abstract: Leafy green vegetables, including lettuce, are recognized as potential vehicles for foodborne pathogens such as Escherichia coli O157:H7. Fresh-cut lettuce is potentially at high risk of causing foodborne illnesses, as it is generally consumed without cooking. Quantitative microbial risk assessments (QMRAs) are gaining more attention as an effective tool to assess and control potential risks associated with foodborne pathogens. This study developed a QMRA model for E. coli O157:H7 in fresh-cut lettuce and evaluated the effects of different potential intervention strategies on the reduction of public health risks. The fresh-cut lettuce production and supply chain was modeled from field production, with both irrigation water and soil as initial contamination sources, to consumption at home. The baseline model (with no interventions) predicted a mean probability of 1 illness per 10 million servings and a mean of 2,160 illness cases per year in the United States. All intervention strategies evaluated (chlorine, ultrasound and organic acid, irradiation, bacteriophage, and consumer washing) significantly reduced the estimated mean number of illness cases when compared with the baseline model prediction (from 11.4- to 17.9-fold reduction). Sensitivity analyses indicated that retail and home storage temperature were the most important factors affecting the predicted number of illness cases. The developed QMRA model provided a framework for estimating risk associated with consumption of E. coli O157:H7-contaminated fresh-cut lettuce and can guide the evaluation and development of intervention strategies aimed at reducing such risk.
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, 20742.
authors.forename: Hao
authors.initials: H
authors.lastname: Pang
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, 20742.|Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland, 20742.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Lambertini
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, 20742.|Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland, 20742.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Buchanan
authors.affiliation: Department of Food Science, Rutgers University, New Brunswick, New Jersey 08901, USA.
authors.forename: Donald W
authors.initials: DW
authors.lastname: Schaffner
authors.affiliation: Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, 20742.|Center for Food Safety and Security Systems, University of Maryland, College Park, Maryland, 20742.
authors.forename: Abani K
authors.initials: AK
authors.lastname: Pradhan
mesh_terms: D015169:Colony Count, Microbial; D019453:Escherichia coli O157; D005506:Food Contamination; D005511:Food Handling; D005516:Food Microbiology; D006801:Humans; D018545:Lactuca; D018570:Risk Assessment
keywords: Escherichia coli O157:H7; Fresh-cut lettuce; Intervention strategies; Risk assessment