

@article {5514,
	title = {{Abiotic stress and phyllosphere bacteria influence the survival of human norovirus and its surrogates on preharvest leafy greens}},
	journal = {Applied and Environmental Microbiology},
	volume = {82},
	number = {1},
	year = {2016},
	pages = {352{\textendash}363},
	abstract = {{\textless}p{\textgreater}Foodborne outbreaks of human noroviruses (HuNoVs) are frequently associated with leafy greens. Because there is no effective method to eliminate HuNoV from postharvest leafy greens, understanding the virus survival under preharvest conditions is crucial. The objective of this study was to evaluate the survival of HuNoV and its surrogate viruses murine norovirus (MNV), porcine sapovirus (SaV) and Tulane virus (TV) on preharvest lettuce and spinach that were subjected to abiotic stress (physical damage, heat or flood). We also examined the phyllosphere culturable bacteria in response to abiotic stress and in relation with viral persistence. Mature plants were subjected to stressors two days prior to viral inoculations on leaves. Quantification of viral RNA, infectivity of surrogates and bacterial counts were performed on post-inoculation days (PID) 0, 1, 7 and 14. For both plant types, time exerted significant effects on HuNoV, MNV, SaV and TV RNA titers, with larger effects on surrogates. Infectious surrogate viruses were undetectable on PID14. Only physical damage on PID14 significantly enhanced HuNoV RNA persistence on lettuce while the three stressors differentially enhanced the persistence MNV and TV RNA. Bacterial counts were significantly affected by time and plant type but not by the stressors. However, bacterial counts correlated significantly with HuNoV RNA titers on spinach and with surrogate viruses on both plant types under various conditions. In conclusion, abiotic stressors and phyllosphere bacterial density differentially influenced the survival of HuNoV and its surrogates on lettuce and spinach, emphasizing the need for preventive measures at the preharvest stage.{\textless}/p{\textgreater}},
	issn = {10985336},
	doi = {10.1128/AEM.02763-15},
	author = {Esseili, Malak A. and Gao, Xiang and Tegtmeier, Sarah and Saif, Linda J. and Wang, Qiuhong}
}
