Reality research: Norovirus in restaurant bathrooms

Long-time friend and friend of the, Don Schaffner, a professor of microbiology at Rutgers University (right, sort of as shown) writes:

More than seven years ago I had the good fortune to be contacted by my colleague, Dr. Lee-Ann Jaykus (below, left, exactly as shown).

She asked if I wanted to be involved in what was at the time going to be a remarkable endeavor. She was going to lead a team of scientists competing to earn a $25 million grant from the USDA focused on understanding Norovirus.

Norovirus causes more foodborne disease than any other microorganism. Because it is often self-limiting, and seldom fatal, it gets a little attention. It’s also a remarkably difficult organism to study. One of the reasons it has been difficult to study is that there had no way to culture the organism outside it’s human host. This meant that anyone wanting to do research with the organism had to have a supply of frozen poop containing the virus.

One of the goals of the ambitious project lead by Dr. Jaykus was to finally crack the code which would allow scientists to culture the virus in the laboratory. Spoiler alert, we got the grant. We were all excited to learn recently that thanks in large measure to the USDA Grant, that riddle has been solved.

This USDA Grant also allowed a number of other research projects too numerous to recount here, but I do want to tell the story of one.

Early on in our efforts on the ground, my colleague, Angie Fraser reached out and asked if I wanted to be part of an extensive survey of restaurant bathroom for Norovirus. I was delighted to say yes, and we began

I have to express my sincere appreciation to Cortney Leone whom led the project. She had the unenviable task of having to oversee researchers in three U.S. states, charged with collection of the data for this project. I also owe huge debt of gratitude to my graduate student Hannah Bolinger who led our data collection efforts in New Jersey.  Thanks also to the NJ team of graduate students, undergraduate students and significant others who visited public bathrooms around the state (Louis Huang, Pierce Gaynor, Sarah Hossain, Sneha Sreekumar, Jenny Todd-Searle, and Arthur Todd-Searle).

(Schaffner, this isn’t an Academy Award acceptance speech, on with it — dp.)

Because we wanted to ensure that our data were representative, we collected data from nine different counties in New Jersey. This turned out to be a lot harder than you might think. New Jersey is a home rule state.

This means that public health operates at the municipal level, with minimal oversight from the state. Our first task was to compile lists of food service establishment from the three regions of New Jersey.

This was easy to do in less densely populated regions, where the municipal entity was the county. We could simply contact the county, and through appropriate freedom of information act paperwork, obtain a list of all of the restaurants in the county. This was far more difficult in the densely settled parts of the state, where obtaining a list require contacting each and every municipality in the county, and filling out each municipalities’ different paperwork, in some cases mailing a paper check to cover photocopying costs, and then eventually taking the information we received back, and putting it into a standardized database. All of this was required before we could even begin to collect the first piece of data.

Thanks to Hanna’s outstanding work, we were eventually able to produce a robust enough database that we could proceed with data collection. Hannah lead a team of students that visited restrooms in and around New Jersey. This was harder than it sounded, as often the information provided by the  municipalities was out of date, and the students arrived at a location, only to learn that the restaurant was closed, or the location was incorrect.

Eventually, the teams in all three states had collected enough swabs and sent the samples back to CDC for analysis.

The end result of all this work was published in the Journal of Food Protection. Although our goal was to visit 750 commercial food establishments, we actually visited 751 establishments, in which 1,044 bathrooms and 4,163 surfaces were swabbed.  Four swab samples were collected from each bathroom: (i) the underside of the toilet seat where it connects to the toilet bowl, (ii) the flush handle of the toilet, (iii) the inner door handle of the stall door or, when there was no stall door, the inner door handle of the outer door, and (iv) the hot water knob of the sink faucet.

In the end 61 (1.5%) of 4,163 swabs were presumptively positive for human norovirus, and 9 of these were confirmed by sequencing.  This is similar to what others have found.

Almost half (30) of positive swabs were found on the underside of the toilet seat. About 20% were found on the toilet flush handle (13) and the inner handle of the stall or outer door (11). Only 11% (7) of positive swabs were found on the sink faucet handle.  Our results suggest that areas further away from the toilet are less likely to harbor norovirus contamination; toilet surfaces (especially the underside of the seat) would be closest to vomiting and diarrheal events during which high numbers of norovirus particles could be shed.

Chain restaurants had significantly more positive samples than non-chains (p = 0.0273). Unisex bathrooms had significantly more positive samples than female bathrooms (p = 0.0163).  Bathrooms with bar soap had significantly more positive samples than liquid soap bathroom (p = 0.0056) and foam soap bathrooms (p = 0.0147), but note that only 3 bathrooms out of 751 actually used bar soap. Bathrooms containing a trash can attached to the paper towel dispenser had significantly more positive samples than bathrooms with a free-standing trash can (p = 0.0004).

Although[the NoroCORE grant recently ended,I know there will be continued publications coming for many years, several of which will come from my lab, that will serve to further advance our understanding of Norovirus, and the means by which it can be controlled.

Prevalence of Human Noroviruses in Commercial Food Establishment Bathrooms


Although transmission of human norovirus in food establishments is commonly attributed to consumption of contaminated food, transmission via contaminated environmental surfaces, such as those in bathrooms, may also play a role. Our aim was to determine the prevalence of human norovirus on bathroom surfaces in commercial food establishments in New Jersey, Ohio, and South Carolina under nonoutbreak conditions and to determine characteristics associated with the presence of human norovirus. Food establishments (751) were randomly selected from nine counties in each state. Four surfaces (underside of toilet seat, flush handle of toilet, inner door handle of stall or outer door, and sink faucet handle) were swabbed in male and female bathrooms using premoistened macrofoam swabs. A checklist was used to collect information about the characteristics, materials, and mechanisms of objects in bathrooms. In total, 61 (1.5%) of 4,163 swabs tested were presumptively positive for human norovirus, 9 of which were confirmed by sequencing. Some factors associated with the presence of human norovirus included being from South Carolina (odd ratio [OR], 2.4; 95% confidence interval [CI], 1.2 to 4.9; P < 0.05) or New Jersey (OR, 1.7; 95% CI, 0.9 to 3.3; 0.05 < P < 0.10), being a chain establishment (OR, 1.9; 95% CI, 1.1 to 3.3; P < 0.05), being a unisex bathroom (versus male: OR, 2.0; 95% CI, 0.9 to 4.1; 0.05 < P < 0.10; versus female: OR, 2.6; 95% CI, 1.2 to 5.7; P < 0.05), having a touchless outer door handle (OR, 3.3; 95% CI, 0.79 to 13.63; 0.05 < P < 0.10), and having an automatic flush toilet (OR, 2.5, 95% CI, 1.1 to 5.3; 0.05 < P < 0.10). Our findings confirm that the presence of human norovirus on bathroom surfaces in commercial food establishments under nonoutbreak conditions is a rare event. Therefore, routine environmental monitoring for human norovirus contamination during nonoutbreak periods is not an efficient method of monitoring norovirus infection risk.

The vomit machine lives on; norovirus can aerosolize during vomit events

I’ve been lucky to be close to some excellent projects, some of the stuff and knowledge created through these projects ends up mattering to food safety nerds – especially those who are making risk management decisions. Former NC State student Grace Tung-Thompson’s PhD project on vomit spray and norovirus is one of the most impactful. The work was carried out as part of the USDA NIFA-funded NoroCORE project led by my friend Lee-Ann Jaykus.VOMIT-BLOG-HEADER-698x393

I’ve talked to lots of Environmental Health Specialists, retailers and food service food safety folks about what Grace and fellow graduate student Dominic Libera put together and many respond with a weird level of enthusiasm for the barf project.

Mainly because a real question they struggle with is how far will virus particles travel from an up-chuck event – knowing this, and then cleaning and sanitizing helps limit the scope of a potential outbreak.  Grace’s work was published in PLOS ONE a while ago, we used it as a centerpiece for a Conference for Food Protection issue on vomit clean up in 2016 (which, maybe, could be included in the oft rumored 2017 Food Code) and the Daily Beast  covered the work today.

A couple of years ago, PhD student Grace Tung Thompson demonstrated something incredibly gross: When a person vomits, little tiny bits of their throw-up end up airborne. You could ingest them just by breathing air in the same room. As if that weren’t disconcerting enough, if the person got sick from a virus, there could be enough viruses in the air to get you sick, too. Just try not to think about that the next time the person in the row behind you throws up on an airplane.
So how do you get rid of airborne viruses? “There is no known technology that will eliminate norovirus if it’s in the air,” Jaykus said, “and there really aren’t a lot of technologies—safe technologies—that even are likely to work.” Her research team recently experimented with misting antiviral compounds into spaces as an alternative to disinfecting surfaces individually, and it worked, but not completely. This technique, known as fogging, can only be used in spaces that can be cleared out and contained, like bathrooms, for example. “I think we need that technology, and that technology is really, really important, but how the heck we’re going to develop it? I’m at a loss for words.”

From an individual perspective, the best you can do is get yourself far away from a vomiting incident; Jaykus recommends at least 100 feet. If you were in the middle of a meal at a restaurant and someone at the next table threw up, you’d probably be wise to stop eating, and to wash yourself and your clothes when you are able.

From the perspective of a restaurant owner, the best course of action is to do a really, really good job of the cleanup. Commercial vomit and fecal matter cleanup kits are catching on with bigger companies in the foodservice industry, says Jaykus. They provide personal protection, including disposable coveralls and respirator masks, in addition to the material required to pick up and wipe down the mess.

Katie’s Norovirus Nightmare

The NoroCORE Collaborative is running a series of posts for Halloween on norovirus nightmares. The first post comes from one of my graduate students, Katie Overbey.

During Spring Break of 2014 I was spent the week with my boyfriend in New Orleans and we stayed with my aunt. As one does in New Orleans, we ate lots of tasty food and tried lots of drinks. On the Saturday of our trip, after eating at my aunt’s favorite Mexican restaurant (side note: who eats Mexican food when they visit New Orleans?) she decided to take us on what has since been deemed the ‘drinking tour of the French Quarter.’ KatieOverbeyAfter about three hours I started to feel queasy right in the middle of the iconic Pat O’Briens Bar. We thought maybe I was hungry from our day of activities so we headed to get dinner. The place was packed and while waiting for our food, it hit me. I weaved through the crowd to get to the bathroom, just to discover that one stall was broken, the other was occupied and there was a line. I apologized to the people in line for what was about to happen and then proceeded to throw up in the sink, because as anyone who’s had norovirus knows – when it decides to hit, there’s not much you can do.

After cleaning up as best I could (though after my master’s research I now know that bathroom was doomed because of all my aerosolized vomit) we headed back to my aunt’s as fast as possible. I proceeded to get sick all night long, which ironically put a damper on the rest of my relaxing vacation.

At first, my aunt and boyfriend thought I had enjoyed the drinking tour too much, but I knew that what I had was way worse. I suspect that it had something to do with the Mexican food because after my aunt ate some of my leftovers, she got sick too.

Katie Overbey is an MS student in Food Science at NC State studying how to better communicate with schools having norovirus outbreaks and environmental detection of norovirus

Norovirus surrogates are tough to inactivate in cotton and polyester

A couple of years ago Sam, the almost-5-year-old yacked all over the backseat of the van on a car trip. The polyester carpeting and cotton fabric-covered seats smelled for weeks. We even tried to hose the van out, leaving the doors open for a couple of days (and then a frog set up shop in there).

It was most likely motion sickness that led to Sam’s vomit event, but people with noro puke on all sorts of surfaces. My friend Angie Fraser and colleagues at Clemson just published what happens when you try to inactivate norovirus surrogates on different surfaces including polyester and glass.

From the discussion: images

Our results indicated that surface and virus type had a significant influence on RE (that’s recovery efficiency – ben). We found that both FCV and MNV exhibited higher RE when inoculated onto glass than either polyester or cotton. In addition, the recovery of both viruses from cotton was significantly lower than that of polyester. Compared with FCV, MNV exhibited a higher recovery from soft porous surfaces; however, it was only significant for cotton. Previous studies have also document- ed the ability of HuNoV surrogates to be recovered with greater efficiency from hard nonporous surfaces than from soft porous surfaces. Viruses may become more tightly bound to soft porous surfaces due to their ability to absorb the virus-containing media and trap viruses in the subsurface.

Recovery and Disinfection of Two Human Norovirus Surrogates, Feline Calicivirus and Murine Norovirus, from Hard Nonporous and Soft Porous Surfaces

Journal of Food Protection, Number 10, October 2015, pp. 1776-1924, pp. 1842-1850(9)

Yeargin, Thomas; Fraser, Angela; Huang, Guohui; Jiang, Xiuping


Human norovirus is a leading cause of foodborne disease and can be transmitted through many routes, including environmental exposure to fomites. In this study, both the recovery and inactivation of two human norovirus surrogates, feline calicivirus (FCV) and murine norovirus (MNV), on hard nonporous surfaces (glass) and soft porous surfaces (polyester and cotton) were evaluated by both plaque assay and reverse transcription quantitative PCR method. Two disinfectants, sodium hypochlorite (8.25%) and accelerated hydrogen peroxide (AHP, at 4.25%) were evaluated for disinfection efficacy. Five coupons per surface type were used to evaluate the recovery of FCV and MNV by sonication and stomaching and the disinfection of each surface type by using 5 ml of disinfectant for a contact time of 5 min. FCV at an initial titer of ca. 7 log PFU/ml was recovered from glass, cotton, and polyester at 6.2, 5.4, and 3.8 log PFU/ml, respectively, compared with 5.5, 5.2, and 4.1 log PFU/ml, respectively, for MNV with an initial titer of ca. 6 log PFU/ml. The use of sodium hypochlorite (5,000 ppm) was able to inactivate both FCV and MNV (3.1 to 5.5 log PFU/ml) below the limit of detection on all three surface types. AHP (2,656 ppm) inactivated FCV (3.1 to 5.5 log PFU/ml) below the limit of detection for all three surface types but achieved minimal inactivation of MNV (0.17 to 1.37 log PFU/ml). Reduction of viral RNA by sodium hypochlorite corresponded to 2.72 to 4.06 log reduction for FCV and 2.07 to 3.04 log reduction for MNV on all three surface types. Reduction of viral RNA by AHP corresponded to 1.89 to 3.4 log reduction for FCV and 0.54 to 0.85 log reduction for MNV. Our results clearly indicate that both virus and surface types significantly influence recovery efficiency and disinfection efficacy. Based on the performance of our proposed testing method, an improvement in virus recovery will be needed to effectively validate virus disinfection of soft porous surfaces.

NC State researchers show copper affects norovirus capsid

Matt Shipman, public information officer at NC State University and curator of The Abstract writes, norovirus affects an estimated 20 million Americans every year, and the hardy virus can linger on exposed surfaces for weeks – making it difficult to stop the spread of the disease. But a new finding from NC State researchers shows that an age-old commodity may be a new tool in combating norovirus: copper.pennies-435cs051012-1

The researchers found that viral shells (being used as a stand-in for norovirus) that were in contact with copper alloys for at least ten minutes became effectively neutralized. In other words, the finding means that virus particles that land on a copper doorknob or counter-top would no longer be capable of causing a norovirus infection.

The work holds promise for helping to limit the spread of norovirus infection via “environmental contamination” in places like hospitals or doctor’s offices.

A paper on the finding, “Destruction of the Capsid and Genome of GII.4 Human Norovirus Occurs During Exposure to Metal Alloys Containing Copper,” is published online in the journal Applied and Environmental Microbiology. The paper was authored by NC State researchers Chip Manuel, Matt Moore, and Lee-Ann Jaykus, who are part of the NoroCORE research collaborative. NoroCORE stands for the Norovirus Collaborative for Outreach, Research, and Education, and involves more than 30 research teams from 18 institutions. It is funded through a $25 million grant awarded by the USDA National Institute of Food and Agriculture.

More information on the work is also available on the site of the American Society for Microbiology.