Performance evaluation of a dead-end hollowfiber ultrafiltration method for enumeration of somatic and F+ coliphage from recreational waters

Assessing cross-laboratory performance for quantifying coliphage using EPA Method 1642

“…The wider method criteria for F + coliphage, which currently spans between detection and 100%, needs to be improved upon. In this study, the spiking suspension had a significant impact on F + recoveries, which is consistent with other efforts evaluating the effect of spiking suspension (Korajkic et al, 2021). Korajkic et al (2021) also found that the method used to titre the spiking suspension significantly affected recoveries, with DLA (the method used in this study and recommended in the current Method 1642) leading to lower F + coliphage recoveries compared to using a SAL assay for spiking suspension enumeration.…”

“…In this study, the spiking suspension had a significant impact on F + recoveries, which is consistent with other efforts evaluating the effect of spiking suspension (Korajkic et al, 2021). Korajkic et al (2021) also found that the method used to titre the spiking suspension significantly affected recoveries, with DLA (the method used in this study and recommended in the current Method 1642) leading to lower F + coliphage recoveries compared to using a SAL assay for spiking suspension enumeration. Both types of spiking suspension and titre method may lead to higher F + coliphage recoveries overall and warrant further evaluation, particularly due to potential impact on the current criteria range.…”

“…The EPA criteria assume the use of MS2‐spiked samples, but our findings highlight the potential for higher recoveries from environmental samples, which will likely be more similar to a mixed sample like wastewater versus a specific type of F + phage, like MS2. A recent study that also evaluated the impact of spiking suspension on recovery observed similar results, with wastewater as the spiking material resulting in significantly higher recoveries when compared to MS2 for F + coliphage (Korajkic et al, 2021).…”

“…In other studies that have looked across a wider range of water types, a matrix has had an influence on recovery, with recovery dependent on location and water type. Korajkic et al (2021) observed significantly reduced recoveries in marine water with relatively high silicic acid concentrations, while McMinn et al (2017) observed higher recoveries in marine versus river water with varying levels of turbidity.…”

Assessment of two volumetrically different concentration approaches to improve sensitivities for SARS-CoV-2 detection during wastewater monitoring

“…Technologies such as hollow-fiber ultrafilters (HFUF), repurposed medical dialysis filters, have been utilized for this application and have shown effectiveness in recovery of diverse microorganisms of interest from a variety of liquid matrices ( Cuevas-Ferrando et al, 2021 , Liu et al, 2012 , McMinn et al, 2017 , Morales-Morales et al, 2003 ). Upon sample concentration, washing of captured microorganisms from the ultrafilter surfaces is performed using a mild surfactant solution which allows for recovery of both viable and non-viable microorganisms present ( Hill et al, 2005 , Korajkic et al, 2021 ). Methods capable of relaying infectious virus status are critical to understanding the risk to public health, establishing the fate and transport of viral pathogens like SARS-CoV-2 (and viral variants) through wastewater, and determining viral persistence.…”