ARS | Publication request: Differences in the binding of human norovirus to and from Romaine lettuce and raspberries by water and electrolyzed waters

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 5, 2011
Publication Date: August 5, 2011
Repository URL: http://doi:10.4315/0362-028X.JFP-10-494
Citation: Tian, P., Yang, D., Mandrell, R.E. 2011. Differences in the binding of human norovirus to and from Romaine lettuce and raspberries by water and electrolyzed waters. Journal of Food Protection. 74(8):1364-1369.

Interpretive Summary: Noroviruses (NoV) annually cause millions of cases of gastrointestinal disease in the United States. Contamination of fresh produce with human NoV (hNoV) could occur through contamination in the field, by food handlers during harvest or packaging, or during processing. We assessed the effectiveness of simple wash steps in removing hNoV contamination with raspberries and romaine lettuce spiked with hNoVs. We determined that a simple rinsing or soaking in water was able to remove >95% of hNoV from spiked contaminated raspberries. In contrast, only 70% of hNoV was removed from romaine lettuce by rinsing in water. We visualized recombinant NoV viral like particles (rNVLP) on romaine lettuce by immunofluorescence microscopy. We tested also different electrolyzed waters (EW) in removing hNoV from lettuce and determined that only 5% of hNoV was removed by acid EW (pH 2.2), suggesting that this treatment enhanced the binding of hNoV to lettuce. Acid EW was compared to neutral EW (pH 8) and basic EW (pH 11) and revealed much better removal of hNoV from lettuce and raspberries by the neutral and basic EW compared to acidic EW. Differences in binding and removal of hNoV to and from produce types associated with illness emphasize the need for further research of hNoV contamination and sanitization of produce.

Technical Abstract: Noroviruses (NoV) annually cause millions of cases of gastrointestinal disease in the United States. Contamination of fresh produce with human NoV (hNoV) could occur through contamination in the field, by food handlers during harvest or packaging, or during processing. We assessed the effectiveness of simple wash steps in removing hNoV contamination with raspberries and romaine lettuce spiked with hNoVs. We determined that a simple rinsing or soaking in water was able to remove >95% of hNoV from spiked contaminated raspberries. In contrast, only 70% of hNoV was removed from romaine lettuce by rinsing in water. We visualized recombinant NoV viral like particles (rNVLP) on romaine lettuce by immunofluorescence microscopy. We tested also different electrolyzed waters (EW) in removing hNoV from lettuce and determined that only 5% of hNoV was removed by acid EW (pH 2.2), suggesting that this treatment enhanced the binding of hNoV to lettuce. Acid EW was compared to neutral EW (pH 8) and basic EW (pH 11) and revealed removal of 6, 75 and 83% of hNoV from lettuce and 12, 99.5 and 31% of hNoV from raspberries, respectively. Differences in binding and removal of hNoV to and from produce types associated with illness emphasize the need for further research of hNoV contamination and sanitization of produce.