Risk ranking of microbial hazards from consumption of ready-to-eat fresh produce (RTEFP)

The consumption of contaminated Ready-To-Eat Fresh Produce (RTEFP), especially minimally processed leafy green vegetables and fruits, is increasingly recognised as a source of foodborne illnesses, posing a significant safety risk to human health. RTEFP can become contaminated with enteric foodborne pathogens via different sources. Water used during the pre-harvest (irrigation) and post-harvest (washing water) has been identified as a potentially important transmission route for foodborne pathogens entering horticultural crops. The objective of the present study was to (i) evaluate human exposure to indicator microorganisms, which may act as a surrogate to assess potential exposure to harmful pathogens, and (ii) create a Quantitative Microbial Risk Assessment (QMRA) to assess the human health safety risks (infection or illness) from foodborne pathogens following the application of treated irrigation (sprinkler) water to RTEFP and assess potential microbial intake through the consumption of RTEFP grown on irrigated land. A QMRA based on published literature was constructed to analyse microbial daily/annual risk to foodborne enteric pathogens associated with consuming ready-to-eat fresh produce. The likelihood of exposure to target pathogens was determined using different model parameters. The results show that the pathogens were prioritised as Shigella spp., Cryptosporidium parvum, Salmonella spp., Giardia lamblia based on probability of illness and Campylobacter spp., norovirus, adenovirus and rotavirus based on probability of infection. Sensitivity analysis revealed that the consumption of RTE fresh produce and cumulative decay constant of pathogens are the most sensitive parameters of the QMRA model, followed by the initial concentration of pathogens, chlorine treatment, growth on shelves, and finally, the effect of cold storage. This study highlighted that chlorine used pre and post-harvest was an effective remedial measure to assist food safety. The study highlights the need for risk-benefit in balancing potential chemical (chlorine) human exposure and the benefits of reduced microbial loads on RTEFP.