Occurrence and Accumulation of Human Enteric Viruses and Phages in Process Water from the Fresh Produce Industry

Abstract

The virological quality of process water (PW) used by the produce industry has received limited attention. As a first step to overcoming technical limitations in monitoring viruses in PW, the analytical performance of ultrafiltration was assessed to concentrate viral particles from 20 L of spiked PW. The selected method used for sample concentration of PW was carefully validated, thus enabling the accurate quantification and estimation of viral titers of human enteric viruses and phages. PW from the produce industry was collected periodically from the washing tanks of commercial facilities. The analysis of coliphages was performed by plaque assay, while the occurrence of enteric viruses and crAssphage was determined by molecular techniques. Significant differences in the physicochemical composition of PW, mostly due to the different nature of fresh produce types and differences in the sanitizer used in commercial operation, were observed. Accumulation of crAssphage and coliphages was observed in PW, but correlation with human enteric viruses was not possible due to the low prevalence of these pathogens in the PW analyzed. The obtained results showed that depending on the type of product washed, the product/water ratio and the residual concentrations of the sanitizers, the prevalence and concentration of bacteriophages changed significantly.

Evaluation of crAssphages as a potential marker of human viral contamination in environmental water and fresh leafy greens

“…positive (Cuevas-Ferrando et al, 2021). In support of this, our study demonstrated the average prevalence rates of crAssphages in irrigation water and fresh leafy greens were 61 and 68.5%, respectively.…”

Antiviral capacity of sanitizers against infectious viruses in process water from the produce industry under batch and continuous conditions

“…One aim of this study was to characterize the antiviral efficacy of chlorine and non-chlorinating agents (e.g., chlorine dioxide and PAA) in PW from three processing operations over time. There is only limited information on the effects of organic matter present in PW on the disinfection performance of human enteric viruses and phages (Cuevas-Ferrando et al, 2021). Some PW characteristics, e.g.…”

“…Physicochemical parameters, together with classical microbial indicators, such as fecal indicator bacteria, including fecal coliforms, Escherichia coli, and enterococci have been widely used to assess the quality of PW used in different postharvest operations. However, studies investigating the presence of human enteric viruses or viral indicators are limited (Cuevas-Ferrando et al, 2021;Dunkin et al, 2017;López-Gálvez et al, 2016;Moreno et al, 2015;Ortiz-Solà et al, 2020). Sanitizers are considered processing aids regulated by the EU (Regulation (EC) No 1333/2008).…”

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). Part 1 (outbreak data analysis, literature review and stakeholder questionnaire)

“…Electrical Conductivity (EC, μS/cm) is the capacity of water to transmit an electrical current and is affected by dissolved solids, which correlated with organic load and should be determined for each type of process water and product (Gombas et al., 2017; Cuevas‐Ferrando et al., 2021; López‐Gálvez et al., 2021).…”

“…Mostly due to the increase of COD in process water where PAA is being used, the measurement of turbidity has been recommended for the assessment of the physico-chemical quality of PAA-treated process water (L opez-G alvez et al, 2020). Electrical Conductivity (EC, lS/cm) is the capacity of water to transmit an electrical current and is affected by dissolved solids, which correlated with organic load and should be determined for each type of process water and product (Gombas et al, 2017;Cuevas-Ferrando et al, 2021;L opez-G alvez et al, 2021).…”