Category Archives: Norovirus

USA – Michigan consumers warned of produce contaminated with human waste

Food Safety News

The Michigan Department of Agriculture and Rural Development (MDARD) is advising consumers not to eat any Kuntry Gardens produce or products containing produce from Kuntry Gardens of Homer, MI, because it may be contaminated with raw, untreated human waste.

All of the implicated products are expected to be labeled under the name Kuntry Gardens.

During a routine produce safety inspection, MDARD staff identified that Kuntry Gardens was using raw, untreated human waste on the fields where produce was grown for sale to local grocery stores and direct sale. The use of raw, untreated, human waste for growing commodities intended for human food is a violation of state and federal laws and regulations.

If not treated professionally, human waste and other body fluids can spread dangerous infectious diseases such as hepatitis A, Clostridium difficile, E. coli, rotavirus and norovirus.

The state health department has placed impacted product still on the farm under seizure and is working with the farm to oversee disposition and corrective action.

USA – More than 200 backpackers and rafters sickened in Grand Canyon National Park backcountry- Suspected Norovirus

Food Safety News

Between April 1 and June 17, 2022, at least 222 rafters and backpackers became infected with acute gastroenteritis, most likely norovirus, according to the Centers for Disease Control and Prevention (CDC). This is the largest outbreak of acute gastroenteritis documented in the Grand Canyon National Park backcountry.

Preliminary analysis of illness characteristics and portable toilet specimen test results suggested norovirus as the primary causative agent of illness. Norovirus spreads quickly through person-to-person contact and contaminated food or beverages and can persist in the environment. The bacteria can live for days to weeks on hard surfaces.

River outfitters and National Park staff members partnered to enable the implementation of prevention and control measures.

Norovirus-associated acute gastroenteritis is highly transmissible in settings with close person-to-person contact and decreased access to hand hygiene. Because many trips use the same campsites and place-portable toilets in the same locations, particles could have been transmitted to surfaces, beach sand or river water where new groups could have encountered them, and then transmitted the virus both from person-to-person and trip-to-trip.

Research – Evaluation of the Impact of Compliance with Mitigation Strategies and Frequency of Restaurant Surface Cleaning and Sanitizing on Control of Norovirus Transmission from Ill Food Employees Using an Existing Quantitative Risk Assessment Model 

Journal of Food Protection



Reduction of foodborne illness caused by norovirus (NoV) continues to be a focus for the food safety community. Using a previously published quantitative risk assessment model, we evaluated more than 60 scenarios examining the impact of implementation of and compliance with risk management strategies identified in the U.S. Food and Drug Administration Food Code for (a) surface cleaning and sanitizing, (b) hand hygiene, (c) exclusion, or (d) restriction of ill employees. Implementation of and compliance with hand hygiene and ill food employee exclusion strategies had the largest impact on the predicted number of highly contaminated food servings and associated consumer illnesses. In scenarios in which gloves were always worn and hand washing compliance was 90%, the model estimated reductions in the number of highly contaminated food servings and ill consumers to 39 and 43% of baseline estimates (i.e., typical practice), respectively. Reductions were smaller when gloves were never worn. Hand washing compliance after using the restroom strongly impacted predicted numbers of highly contaminated servings and consumer illnesses. Ten percent compliance with removing or excluding ill food employees was predicted to increase the number of highly contaminated food servings and ill consumers to 221 and 213% of baseline estimates, respectively. Ninety-four percent compliance with exclusion of ill food employees was predicted to decrease these numbers to 69 and 71% of baseline estimates, respectively. Surface cleaning in food establishments had a relatively small impact on these measures. Restriction of food employees (removed from contact with food and food contact equipment and utensils) was not effective for reducing NoV illness unless this restriction included additional provisions. The results from this study can help risk managers prioritize mitigation strategies and their implementation for controlling the transmission of NoV and subsequent consumer foodborne illness.

  • We adapted a discrete event NoV transmission model for use in a food establishment.
  • Compliance with exclusion and hand hygiene rules had the most impact on consumer illnesses.
  • Washing hands before donning and changing gloves efficiently reduces NoV transfer.
  • Restriction of food employees needs additional provisions to be effective.
  • Surface cleaning and sanitizing has the least impact on consumer illnesses.

RASFF Alert – Norovirus – Oysters –


Norovirus (GI /2g) in live oysters (Crassostrea gigas) from France, via Netherlands in Finland

What Are Common Food Poisoning Pathogen Incubation Periods?

Food Safety Gov

Check out the fact sheets at the link above.

Bacteria and Viruses

Bacteria and viruses are the most common cause of food poisoning. The symptoms and severity of food poisoning vary, depending on which bacteria or virus has contaminated the food.

To prevent illness, always follow the food safety steps: cleanseparatecook, and chill. Other prevention tips for specific bacteria and viruses are included below.

The bacteria and viruses that cause the most illnesses, hospitalizations, or deaths in the United States are described below and include:

Other important bacteria and viruses that cause foodborne illness include:

Research – Risk Assessment of Norovirus Transmission in Food Establishments


The Risk Assessment of Norovirus Transmission in Food Establishments: Evaluating the Impact of Intervention Strategies and Food Employee Behavior (Duret et al. 2017) evaluates the dynamics of norovirus transmission from ill or infected food employees in food establishments (restaurant setting) to ready-to-eat food and consumers during food preparation and also evaluates the impact of prevention strategies. A discrete event model was developed to study norovirus transmission from the soiled hands of ill or infected food employees and the impact of prevention strategies and their compliance on the prevalence of contaminated servings and the number of resulting infected customers.

The Evaluation of the Impact of Compliance with Mitigation Strategies and Frequency of Restaurant Surface Cleaning and Sanitizing on Control of Norovirus Transmission from Ill Food Employees Using an Existing Quantitative Risk Assessment Model (Fanaselle et al. 2022) uses the previously published FDA quantitative risk assessment model in Duret et al. 2017, to evaluate more than 60 scenarios examining the impact of implementation and compliance with recommendations in the FDA Food Code for: restaurant surface cleaning and sanitizing, hand hygiene and employee health.

Research – Interactions Between Infectious Foodborne Viruses and Bacterial Biofilms Formed on Different Food Contact Surfaces


Bacterial biofilms contribute to contamination, spoilage, persistence, and hygiene failure in the food industry, but relatively little is known about the behavior of foodborne viruses evolving in the complex communities that make up biofilm. The aim of this study was to evaluate the association between enteric viruses and biofilms on food contact surfaces. Formed biofilms of mono- and multispecies cultures were prepared on glass, stainless steel, and polystyrene coupons and 105 pfu/ml of murine norovirus, rotavirus, and hepatitis A virus were added and incubated for 15 min, 90 min, and 24 h. The data obtained clearly demonstrate that the presence of biofilms generally influences the adhesion of enteric viruses to different surfaces. Many significant increases in attachment rates were observed, particularly with rotavirus whose rate of viral infectious particles increased 7000 times in the presence of Pseudomonas fluorescens on polystyrene after 24 h of incubation and with hepatitis A virus, which seems to have an affinity for the biofilms formed by lactic acid bacteria. Murine norovirus seems to be the least influenced by the presence of biofilms with few significant increases. However, the different factors surrounding this association are unknown and seem to vary according to the viruses, the environmental conditions, and the composition of the biofilm.

Research – Pooled prevalence and genetic diversity of norovirus in Africa: a systematic review and meta-analysis

Virology J

Food Borne Illness - Norovirus -CDC Photo



Noroviruses are the leading cause of acute gastroenteritis in all age groups globally. The problem is magnified in developing countries including Africa. These viruses are highly prevalent with high genetic diversity and fast evolution rates. With this dynamicity, there are no recent review in the past five years in Africa. Therefore, this review and meta-analysis aimed to assess the prevalence and genetic diversity of noroviruses in Africa and tried to address the change in the prevalence and genetic diverisity the virus has been observed in Africa and in the world.


Twenty-one studies for the pooled prevalence, and 11 out of the 21 studies for genetic characterization of norovirus were included. Studies conducted since 2006, among symptomatic cases of all age groups in Africa, conducted with any study design, used molecular diagnostic methods and reported since 2015, were included and considered for the main meta-analysis. PubMed, Cochrane Library, and Google Scholar were searched to obtain the studies. The quality the studies was assessed using the JBI assessment tool. Data from studies reporting both asymptomatic and symptomatic cases, that did not meet the inclusion criteria were reviewed and included as discussion points. Data was entered to excel and imported to STATA 2011 to compute the prevalence and genetic diversity. Heterogeneity was checked using I2 test statistics followed by subgroup and sensitivity analysis. Publication bias was assessed using a funnel plot and eggers test that was followed by trim and fill analysis.


The pooled prevalence of norovirus was 20.2% (95% CI: 15.91, 24.4). The highest (36.3%) prevalence was reported in Ghana. Genogroup II noroviruses were dominant and reported as 89.5% (95% CI: 87.8, 96). The highest and lowest prevalence of this genogroup were reported in Ethiopia (98.3%), and in Burkina Faso (72.4%), respectively. Diversified genotypes had been identified with an overall prevalence of GII. 4 NoV (50.8%) which was followed by GII.6, GII.17, GI.3 and GII.2 with a pooled prevalence of 7.7, 5.1, 4.6, and 4.2%, respectively.


The overall pooled prevalence of norovirus was high in Africa with the dominance of genogroup II and GII.4 genotype. This prevalence is comparable with some reviews done in the same time frame around the world. However, in Africa, an in increasing trained of pooled prevalence had been reported through time. Likewise, a variable distribution of non-GII.4 norovirus genotypes were reported as compared to those studies done in the world of the same time frame, and those previous reviews done in Africa. Therefore, continuous surveillance is required in Africa to support future interventions and vaccine programs.

New Zealand – Consumers urged not to eat illegal mussels


New Zealand Food Safety is urging consumers not to eat mussels being sold illegally at independent retailers or online.

The sale of imported mussels is carefully controlled to ensure they meet New Zealand’s food safety requirements. While mussels from Fiji may be brought into New Zealand for personal use, they cannot be sold.

Deputy director general Vincent Arbuckle says Fijian mussels have been removed from sale at some smaller retailers catering to Pacific Island communities, and online.

“As New Zealand Food Safety has not assessed Fiji’s growing, harvesting and processing controls for mussels we cannot be confident that the mussels don’t pose a food safety risk to consumers.”

The mussels are also known as: Nakai, Naakai, Nakaai, Kai, Batissa violacea and Fresh Water Mussels.

“It’s vital that mussels available to buy for members of the public are safe to eat. Knowing where the mussels you want to buy have come from can help reduce the risk of any potential health problems.

“Our message to people buying mussels is that if you are in any doubt, ask the retailer where the product has come from. If it is from Fiji, the mussels should not be for sale.”

Mussels are a higher risk food because of the way they feed, which increases the likelihood of contamination from bacteria, viruses, toxins and chemicals.

Hong Kong – Pre-shucked Oysters for Raw Consumption – What Should One be Aware of?


french oysters

Raw Oysters are High-risk Foods
Oysters are filter feeders. They constantly draw in water and accumulate materials from water, including pathogens such as Vibrio bacteria, norovirus and hepatitis A virus. These pathogens can infect people who eat oysters raw or undercooked. In addition, bacteria like Vibrio can continue to grow in oysters after harvesting if oysters are not maintained at low enough temperatures from harvest through to consumption. Food poisoning outbreaks related to raw oysters have been reported locally from time to time. Although the illness is usually mild and self-limiting, causing symptoms such as diarrhoea, abdominal cramps and vomiting, they can also cause severe health consequences especially for susceptible individuals.

Additional Risks in Shucked Oysters
Both physical and microbiological contamination are possible during the shucking of oysters. Physical removal of shellfish meat from the shell at the shucking table often exposes the product to dirt, mud and detritus. Shucked oysters should be rinsed or washed well to eliminate these contaminants and to reduce microbiological level of the products. Good hygiene practices should also be observed to minimise contamination from the workers and the working environment.

Before deshelling, oysters can stay alive even after long-haul shipping if kept under correct temperature and conditions. Once killed after shucking, raw oysters can deteriorate quickly if the temperature is not low enough to limit bacterial growth. Shucked oysters should be packed and chilled or frozen as soon as possible. Furthermore, an uninterrupted cold chain during transportation is critical to ensure safety and quality of the shellfish products.

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