USE OF THE DELPHI EXPERT ELICITATION TECHNIQUE TO RANK FOOD SAFETY RISKS IN GREENHOUSE TOMATO PRODUCTION

Abstract

One half of fresh tomato sales in the US are from greenhouse grown crops. Fresh tomato was linked to a number of foodborne disease outbreaks. Collectively, foodborne and phytopathogen hazards threaten both public health and economic viability of the greenhouse industry. Management practices in tomato greenhouses in North America were documented previously. In this study, a systematic, internet-based, iterative Delphi method was used to gauge opinions about the potential impact of various greenhouse management factors (water management, workers, environment and greenhouse design, equipment sanitation, animals, waste, and traceability) on food safety. The pretested questionnaire was distributed to 20 national and international experts in food safety of fresh fruits and vegetables. The Delphi process was repeated until the criteria for consensus were satisfied (expert agreement ≥70%). Expects attributed greenhouse irrigation water as a highly important source of contamination with human pathogens. Accordingly, testing of irrigation water for human pathogens was considered to be a valuable tool in controlling contamination in the greenhouse. According to this expert panel, people may occasionally introduce pathogens into the greenhouse. Hand washing and footwear were ranked the most effective in preventing contamination from employees and visitors. The majority of experts believed the presence of human pathogens in the greenhouse environment presented an important source of contamination for edible tomato fruits. Experts also agreed that livestock and poultry operations should be at least 250 feet away from the greenhouse. Although any animal intrusion was considered a high-extreme food safety risk-rodents were ranked the highest, and cats the lowest. Employee hygiene, mode of irrigation, equipment sanitation was ranked the most important management practice in prevention of contamination with human pathogens.