Farm-to-consumer hazard transmission model

Develop a farm-to-consumer hazard transmission model to facilitate a systems approach to identifying environment appropriate, socially acceptable and cost-effective interventions.

We will characterize contamination of romaine lettuce with Escherichia coli O157:H7 and contamination of cantaloupes with Listeria monocytogenes along the farm-to-table continuum and evaluate different interventions implemented to reduce the consumer exposure to these foodborne pathogens. The goal is to identify interventions that not only improve safety of these foods but are also environment appropriate, socially acceptable and cost-effective.

Food safety risk assessments

Risk assessment of Escherichia coli O157:H7 along the farm-to-fork fresh-cut romaine lettuce supply chain

We conducted a quantitative microbial risk assessment (QMRA) to predict the food safety risk associated with Escherichia coli O157:H7 contamination of fresh-cut romaine lettuce in the United States and evaluate control strategies (Figure 1). Irrigation was identified as a much more important source of E. coli O157:H7 contamination than inadequately treated biological soil amendments, runoff, and wildlife intrusion. At preharvest, the risk of E. coli O157:H7 contamination can be effectively reduced either through irrigation water treatments or by switching from overhead spray to furrow or drip irrigation. At postharvest, an effective postharvest wash and maintaining the cold chain are crucial for preventing illness cases.

Reference:

Bulut, E., Murphy, S.I., Strawn, L.K., Danyluk, M., Wiedmann, M. and Ivanek, R. Identifying preharvest risk reduction strategies for Escherichia coli O157:H7 on fresh-cut romaine lettuce in the US industry through application of QMRA. (under submission)

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

We conducted a quantitative microbial risk assessment (QMRA) to predict the food safety risk associated with Listeria monocytogenes contamination of fresh-cut cantaloupe in the United States and evaluate control strategies (Figure 2). Time and temperature conditions post-packaging, and the initial number of L. monocytogenes at harvest had the greatest impacts on L. monocytogenes per contaminated serving and the number of annual illnesses, while the initial L. monocytogenes at harvest and cross-contamination at the fresh-cut facility had the greatest impacts on prevalence of contaminated servings. Reducing temperature and/or time conditions post-packaging can be an effective risk reduction strategy.

Reference:

Murphy, S.I., Bulut, E., Strawn, L.K., Danyluk, M., Wiedmann, M., and Ivanek, R. Farm-to-consumer quantitative risk assessment model for Listeria monocytogenes on fresh-cut cantaloupe. (under submission)

Sustainability of food safety strategies

Cost-benefit analyses of food safety interventions in reducing Escherichia coli O157:H7 in romaine lettuce and Listeria monocytogenes in fresh-cut cantaloupe

The objective of this study is to investigate the sustainability of food safety interventions within the fresh produce industry through two case studies: (i) Escherichia coli O157:H7 in romaine lettuce and (ii) Listeria monocytogenes in fresh-cut cantaloupe. The setup of the two case studies is described below.

Reference:

Hao, J., Kalunga, L., Bulut, E., Ivanek, R., Adalja, A. Cost-benefit analyses of food safety interventions in reducing Escherichia coli O157:H7 in romaine lettuce and Listeria monocytogenes in fresh-cut cantaloupe. (in writing)

Irrigation and water treatment interventions for reducing E. coli O157:H7 in romaine lettuce

This case study investigates the contamination of romaine lettuce with E. coli O157:H7 through irrigation water. It evaluates the private and public costs and benefits of two irrigation systems—overhead spray and drip—across multiple interventions (Figure 1). The first evaluation focuses on overhead spray irrigation without water treatment (baseline) and with chlorine and peracetic acid (PAA) as separate treatments. The second intervention examines the transition from overhead spray to drip irrigation, comparing both untreated and treated systems (chlorine, PAA, and ultraviolet (UV)). Each intervention is assessed based on economic factors, ecological impact (greenhouse gas emissions), and social outcomes (number of human illness cases predicted under each intervention). This comprehensive approach aims to determine the most effective water treatment method or irrigation system for reducing contamination while balancing costs, public health and ecological considerations.

Optimizing retail and home refrigeration for mitigating L. monocytogenes in fresh-cut cantaloupe

This case study investigates three interventions at the retail and consumer levels to reduce the risk of L. monocytogenes in fresh-cut cantaloupe: transitioning from open to closed refrigeration units at retail, improving household refrigeration practices by lowering refrigerator temperatures, and combining both interventions for joint impact analysis (Figure 2). These interventions are evaluated across economic, ecological (Greenhouse gas emissions (GHGEs)), and social dimensions (number of human illness cases predicted under each intervention), with quantifiable impacts in terms of private and public costs and benefits for the US fresh-cut cantaloupe industry. The analysis utilizes metrics for energy consumption, refrigeration costs, GHGEs, and public health costs derived from risk assessment modeling. This comprehensive approach aims to identify the most effective refrigeration strategies for minimizing contamination risks while optimizing energy efficiency, environmental sustainability, and public health outcomes.

Contact

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Associate Professor of Epidemiology in the Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine.

The overarching goal of Dr. Ivanek’s research is to advance One Health -- the interconnected health of people, animals, plants and their shared environment. Her computer lab develops new and sustainable data- and model-driven approaches for improving food safety, controlling infectious diseases and optimizing food production systems.

Email: ri25@cornell.edu

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Assistant professor of food and beverage management at the School of Hotel Administration and a faculty fellow at the Atkinson Center for a Sustainable Future at Cornell University.

Adalja's research draws on consumer theory, industrial organization, and marketing to examine empirical questions in food and agricultural economics related to food labeling and quality certification, food safety, sustainability, and food and agricultural marketing. His current research includes studies on consumers' and firms' responses to voluntary non-GMO food labeling, the role of collective reputation in produce food safety, grower tradeoffs between farm conservation and food safety, and pricing and labeling strategies to mitigate fluid milk food waste.

Email: aaron.adalja@cornell.edu