Microbiological hazards associated with the use of water in the post-harvest handling and processing operations of fresh and frozen fruits, vegetables and herbs (ffFVHs)

This tender, developed under a self-task mandate from the BIOHAZ Panel, analysed the characteristics of the water and the practices followed by the European food business operators (FBOs) to maintain process water quality used during the post-harvest handling and processing operations for fresh and frozen fruits, vegetables and herbs (ffFVHs) using: information and data obtained from FBOs, experimental data extracted from literature and dynamic mass balance modelling. Quantitative data were obtained from 61 FBO scenarios (29 from the fresh-whole sector, 19 from the fresh-cut sector, and 13 from the frozen sector). The impact of no water treatment was evaluated in 17 scenarios, while in 44, the challenges of maintaining the microbiological quality with water disinfection agents were examined, including chlorine, peroxyacetic acid, and hydrogen peroxide. The findings highlighted that when no water disinfection treatment was used Listeria monocytogenes was detected in some scenarios of the fresh-whole and frozen FVH sectors as well as Salmonella, pathogenic Escherichia coli and norovirus in the fresh-cut and frozen FVH sector. Additionally, inadequate or improper monitoring systems resulted in either excessively high or insufficient disinfectant concentrations in the water, which, when too low, failed to sufficiently reduce the microbial load. The literature review revealed a tendency to: focus on leafy greens, use chlorine-based disinfectants, and employ chemical oxygen demand (COD) as the primary physico-chemical parameter, with total dissolved solids (TDS) and turbidity considered to a lesser extent, as indicators of water quality. Additionally, dynamic mass balance modelling was used to interpret experimental data from literature and FBOs. The model was fundamental to estimate key unknown parameters, predict the microbial contamination and accumulation of organic matter and allowing to simulate “what-if scenarios.”