UV Light Inactivation of Hepatitis A Virus, Aichi Virus, and Feline Calicivirus on Strawberries, Green Onions, and Lettuce

Abstract

A majority of illnesses caused by foodborne viruses are associated with fresh produce. Fruits and vegetables may be considered high-risk foods, as they are often consumed raw without a specific inactivation step. Therefore, there is a need to evaluate nonthermal treatments for the inactivation of foodborne pathogens. This study investigates the UV inactivation of three viruses: feline calicivirus (a surrogate for norovirus), and two picornaviruses, hepatitis A virus and Aichi virus. Three produce types were selected for their different surface topographies and association with outbreaks. Green onions, lettuce, and strawberries were individually spot inoculated with 10(7) to 10(9) 50% tissue culture infective doses (TCID50) of each virus per ml and exposed to UV light at various doses (< or = 240 mW s/cm2), and viruses were eluted using an optimized recovery strategy. Virus infection was quantified by TCID50 in mammalian cell culture and compared with untreated recovered virus. UV light applied to contaminated lettuce resulted in inactivation of 4.5 to 4.6 log TCID50/ml; for contaminated green onions, inactivation ranged from 2.5 to 5.6 log TCID50/ml; and for contaminated strawberries, inactivation ranged from 1.9 to 2.6 log TCID50/ml for the three viruses tested. UV light inactivation on the surface of lettuce is more effective than inactivation on the other two produce items. Consistently, the lowest results were observed in the inactivation of viruses on strawberries. No significant differences (P > 0.05) for virus inactivation were observed among the three doses applied (40, 120, and 240 mW s/cm2) on the produce, with the exception of hepatitis A virus and Aichi virus inactivation on green onions, where inactivation continued at 120 mW s/cm2 (P < 0.05).

Inactivation of Murine Norovirus 1, Coliphage φX174, and Bacillus fragilis Phage B40-8 on Surfaces and Fresh-Cut Iceberg Lettuce by Hydrogen Peroxide and UV Light

“…Nevertheless, for viruses inoculated on lettuce, the viral decline was indeed lower. This result, being consistent with some previous studies (16,27), indicates that due to the sheltering or inaccessibility of the food structures, the interfering effect of real food might be too complicated to be simulated by one simple protein.…”

“…However, this system is rather complex and not yet confirmed by other groups; therefore, surrogate viruses that share common pathological and/or molecular features with human NoVs are used instead. Feline calicivirus (FCV) and coliphage MS2 were almost exclusively used as a surrogate virus in previous studies (1,10,16,36). In 2003, a NoV that infects mice, namely, murine norovirus 1 (MNV-1), was identified (23).…”

Effect of Grape Seed Extract on Human Norovirus GII.4 and Murine Norovirus 1 in Viral Suspensions, on Stainless Steel Discs, and in Lettuce Wash Water

“…Due to the lack of suitable animal models and the inability to propagate in cell cultures for human NoVs (4), surrogates that share pathological and/or biological features with human NoVs have been used to study the inactivation of human NoVs (8,9,17). MNV-1 has been used since it is cultivable and belongs to the same genus as human NoVs (34).…”

Effects of Technological Processes on the Tenacity and Inactivation of Norovirus Genogroup II in Experimentally Contaminated Foods

“…Studies of inactivation of infectious human NV in food are rare. Various inactivation studies have been performed with FCV (17,28,32,35,68,82,86) and murine norovirus (7,8,10,11,21,51), which are cultivable viruses belonging to the family Caliciviridae with ssRNA, as models for NV. The findings of these studies cannot be directly applied to NV because several results indicated that the surrogates are generally more sensitive to physicochemical treatments (21,57).…”

“…Such studies are limited mainly to shellfish (42,43) and berries (18,19) or to cultivable enteric viruses, such as hepatitis A virus (HAV) (15,24,42,66,78), poliovirus (PV) (26,84), or rotavirus (12). Due to the lack of a mammalian cell culture or animal model for norovirus, various studies of persistence and inactivation have been performed with genetically related surrogates of norovirus, including feline calicivirus (FCV) (17,28,32,35,68,82,86) and murine norovirus (MNV) (7,8,10,11,21,51), which are cultivable nonenveloped viruses belonging to the family Caliciviridae. However, the validity of data obtained with these surrogates is limited because these viruses appear to be generally less stable than human NV when they are subjected to physicochemical treatments (21,57).…”