Effect of Temperature and Sanitizers on the Survival of Feline Calicivirus, Escherichia coli, and F-Specific Coliphage MS2 on Leafy Salad Vegetables

The attachment of murine norovirus 1 (MNV) in biosolids, swine manure, and dairy manure to Romaine lettuce and internalization of this virus were evaluated. The MNV in animal manures had behavior similar to that of pure MNV; however, MNV in biosolids had significantly higher levels of attachment and internalization than pure MNV or MNV in manures. The incubation time did not affect the attachment of MNV in biosolids or manure. Confocal microscopy was used to observe MNV on lettuce after SYBR gold-labeled MNV was added directly to lettuce or after lettuce was submersed in labeled virus. MNV was observed on the lettuce surface, inside open cuts, and occasionally within stomata. In general, lettuce pieces with a long cut on the edge and short cuts on the stem was more likely to contain internalized MNV than intact lettuce pieces, as observed by confocal microscopy; however, while the difference was visible, it was not statistically significant. This study showed that the presence of MNV in biosolids may increase the risk of fresh produce contamination and that the MNV in open cuts and stomata is likely to be protected from sanitization.Noroviruses (NoVs) are leading food-borne pathogens, accounting for over 60% of food-borne disease in the United States (15). They are the most common cause of nonbacterial gastroenteritis, and an estimated 23 million cases occur annually in the United States. NoVs are prevalent in the environment and can be found in waste treatment plant influent and effluent (7), biosolids (4), and animal feces (14). Due to these facts, the use of biosolids and animal manure on agricultural land may disseminate human pathogens in the environment and subsequently increase the chance of crop contamination (22). Recently, increasing outbreaks of NoV infection have been associated with salads and vegetables (9,11,13). Fresh produce could be contaminated from preharvest to postharvest at any point in the chain of production, and one of the major routes with a high likelihood of contamination is the use of contaminated water for irrigation and washing (12). Water could be contaminated by the use of biosolids and manure as organic fertilizer on United States farms or by runoff from animal production zones close to produce fields. Changes in processing, including more cutting and coring performed in the field during harvest, also increase the potential risk of microbial contamination. Furthermore, postharvest sanitizing regimens used by industry have a limited effect on the removal or inactivation of enteric viruses on lettuce (1), and since it only takes a few infectious particles to cause an infection, consumption of fresh produce continues to be a public health risk.Intensive studies of the behavior of bacteria such as Escherichia coli, Pseudomonas, and Salmonella on fresh produce have been conducted (2, 3, 16, 17), but little work has been conducted with viruses. It has been reported that E. coli and Pseudomonas can grow on lettuce surfaces (17). While Pseudomonas tended to adhere to intact leaf surfac...

mentioning

confidence: 99%

Manure- and Biosolids-Resident Murine Norovirus 1 Attachment to and Internalization by Romaine Lettuce

Wei¹,

Jin

Sims

et al. 2010

“…MS2 has been used in place of pathogens in a large number of studies: for examining the survival of viruses on produce (1,11), developing systems and methods to remove viruses from water and surfaces (5, 9, 10, 12, 13, 17-20, 23-25, 29, 30, 32-34, 42), and investigating the fate of pathogens in groundwater (2,14,15,26,31,(36)(37)(38)(39). It has also been used in the testing and development of systems for the detection of biological warfare agents (3,8,22,35,40,41).…”

mentioning

confidence: 99%

Real-Time Fluorogenic Reverse Transcription-PCR Assays for Detection of Bacteriophage MS2

O’Connell

Bucher

Anderson

et al. 2006

Bacteriophage MS2 is used in place of pathogenic viruses in a wide variety of studies that range from testing of compounds for disinfecting surfaces to studying environmental transport and fate of pathogenic viruses in groundwater. MS2 is also used as a pathogen simulant in the research, development, and testing (including open air tests) of methods, systems, and devices for the detection of pathogens in both the battlefield and homeland defense settings. PCR is often used as either an integral part of such detection systems or as a reference method to assess the sensitivity and specificity of microbial detection. To facilitate the detection of MS2 by PCR, we describe here a set of real-time fluorogenic reverse transcription-PCR assays. The sensitivity of the assays (performed with primer pairs and corresponding dye-labeled probes) ranged from 0.4 to 40 fg of MS2 genomic RNA (200 to 20,000 genome equivalents). We also demonstrate the usefulness of the primer pairs in assays without dye-labeled probe that included the DNA-binding dye SYBR green. None of the assays gave false-positive results when tested against 400 pg of several non-MS2 nucleic acid targets.

“…Multiple studies evaluating NoV inactivation on surfaces and fresh produce have been recently performed, since they may play an important role in the spread of human NoVs (1,4,8,18,27). Magulski et al (27) tested the inactivating properties of several chemical biocides using MNV-1 as a surrogate for human NoVs and suggested products based upon peroxyacetic acid (0.1%), glutaraldehyde (0.25%), ethanol (50%, vol/vol), and isopropanol (30%, vol/vol) which could inactivate MNV-1 on stainless steel discs by Ն 4 log 10 units within 5 min.…”

Section: Discussionmentioning

confidence: 99%

“…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).…”

mentioning

confidence: 99%

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

Baert

Jonghe

et al. 2011