Persistence of Hepatitis A Virus RNA in Water, on Non-porous Surfaces, and on Blueberries

Abstract

Enteric viruses, such as human norovirus and hepatitis A virus (HAV), are the leading cause of transmissible foodborne illness. Fresh produce such as berries are often contaminated by infected food handlers, soiled water, or food contact surfaces. The gold-standard method for virus detection throughout the food chain is RT-qPCR, which detects portions of genomes including non-infectious viral particles and naked viral RNA. The aim of this study was to evaluate the persistence of heat-inactivated HAV in water, phosphate-buffered saline, on stainless steel and polyvinyl chloride, and on blueberries at -80°C, -20°C, 4°C, and room temperature. In water and phosphate-buffered saline, viral RNA could be detected for up to 90 days regardless of temperature when the initial load was 2.5 × 10⁴ or 2.5 × 10⁶ genome copies. It was detected on polyvinyl chloride and blueberries under most conditions. On stainless steel, the large initial load persisted for 90 days, while the medium-level load was detected only up to 16 days at room temperature or 60 days at 4°C. The detection of non-infectious viral RNA can confound investigations of gastroenteritis outbreaks. Pretreatments that discriminate between naked RNA, non-infectious virions and infectious virions need to be included in the RT-qPCR method in order to reduce the risk of positive results associated with non-infectious viral particles.

Keywords: RNA; blueberries; food contact surfaces; hepatitis A; persistence; water.

FIGURE 1

Persistence of inactivated HAV in water (molecular biology grade) initially at 2.5 × 10⁶ genome copies per 100 μL from (A) 30 min to 4 days and (B) 8 days to 90 days and at 2.5 × 10⁴ genome copies per 100 μL from (C) 30 min to 4 days and (D) 8 days to 90 days at –80°C (),–20°C (), 4° C (), and 23°C (). Plotted values are means of 3 repetitions ± standard deviation.

FIGURE 2

Persistence of inactivated HAV dried on inert material surfaces initially at 2.5 × 10⁶ genome copies per unit (disk, diameter 1 cm) from (A) 30 min to 4 days and (B) 8 days to 90 days and at 2.5 × 10⁴ genome copies per unit from (C) 30 min to 4 days and (D) 8 days to 90 days at 4° C on SS (), 23°C on SS (), 4° C on PVC (), and 23°C on PVC (). Plotted values are means of 3 repetitions ± standard deviation.

FIGURE 3

Persistence of inactivated HAV dried on blueberries at two initial loads from (A) 30 min to 4 days and (B) 8 days to 90 days. 2.5 × 10⁶ genome copies per blueberry at –20°C () and 4° C () and 2.5 × 10⁴ genome copies per blueberry at –20°C () and 4° C () Plotted values are means of 3 repetitions ± standard deviation.