lundi 27 mars 2017

Retail Shops and Foodborne Virus Control

Fresh vegetables and their ready-to-eat (RTE) salads have become increasingly recognized as potential vehicles for foodborne diseases. The EU Reg. 1441/2007 establishes microbiological criteria for bacterial pathogens for products placed on the market during their shelf-life for pre-cut fruits and vegetables (RTE) whilst it does not address the problem of contamination by enteric viruses.

Ready-To-Eat Virus Contamination

In this study contamination by :
  • hepatitis A virus (HAV),
  • hepatitis E virus (HEV) and
  • norovirus (NoV)
was investigated in 911 ready-to-eat vegetable samples taken from products at retail in Apulia and in Lombardia.

Apulia, Italy
Résultat d’images pour lombardia
Lombardia, Italy

The vegetable samples were tested using validated real-time PCR.

Prevalence of foodborne Hepatitis Virus

The total prevalence of HAV and HEV was 1.9% (18/911) and 0.6% (6/911), respectively. The detection of HAV and HEV in RTE salads highlights a risk to consumers and the need to improve production hygiene. Appropriate implementation of hygiene procedures is required at all the steps of the RTE vegetable production chain.
This should include monitoring of emerging viral pathogens.

Presence of Norovirus &Adenovirus on Environmental Surfaces

Norovirus (NoV) gastroenteritis outbreaks appear frequently in food service operations (FSOs), such as in restaurants and canteens. In this study the presence of NoV and adenovirus (AdV) genomes was investigated on the surfaces of premises, especially in kitchens, of 30 FSOs where foodborne gastroenteritis outbreaks were suspected.

The objective was to establish a possible association between the presence of virus genomes on surfaces and a visual hygienic status of the FSOs. NoV genome was found in 11 and AdV genome in 8 out of 30 FSOs.

Positive swabbing with Norovirus and Adenovirus

Swab sampling method have been developped to address the issue In total, 291 swabs were taken, of which 8.9% contained NoV and 5.8% AdV genome. The study suggests that
  • swabbing is necessary for revealing viral contamination of surfaces
  • emphasis of hygiene inspections should be on the food handling procedures,
  • the education of food workers on virus transmission is key.

Norovirus cross-contamination during preparation of fresh produce

The goal of this study was to examine cross-contamination of a HuNoV surrogate, murine norovirus (MNV-1), during common procedures used in preparing fresh produce in a food service setting, including turning water spigots, handling and chopping Romaine lettuce, and washing hands. The data gathered indicate that MNV-1 transfers readily between common surfaces during food preparation.

The Federation of Commerce and Distribution and Foodborne virus

The Federation of Commerce and Distribution in France, a Professional Group gathering supermarkets (retail shops), publishes GUIDELINES for the control of Norovirus and Hepatitis A Virus in many food matrices, including Frozen Fruits, Scallops, Live bivalve shellfish, Herbs and salads (leafy greens).

Foodborne Virus and Regulations in Europe

Résultat d’images pour dura lex sed lex


Foodstuffs should not contain micro-organisms or their toxins or metabolites in quantities that present an unacceptable risk for human health, according to CE/2073/2005.


Frozen raspberries (food) originating from Serbia at a control frequency of 10% due to their possible contamination with norovirus (CE) n°669/2009

HACCP and Control Plan for Foodborne Virus

The main reasons for using HACCP are to implement food safety management and prevent food safety hazards. By identifying where hazards are most likely to occur in the operation it will be much easier to put in place the measures needed to prevent those hazards, especially the ones concerned by Foodborne viruses (Norovirus and Hepatitis A Virus). In addition, food safety incidents, such as the Pomegranate seeds contamination by HAV, or the Frozen Strawberries originating from Egypt and contaminated by Hepatitis A Virus, can be prevented by an effective HACCP system.

Virus Outbreaks in Europe in 2017

Norovirus and Hepatitis A Virus Outbreaks in Europe in 2017
Molluscs, Fruits and Vegetable have been implicated in outbreaks in 2017, originating from no less than seven countries. Norovirus was the most common foodborne virus (92%). Italy has been the greatest provider of Alerts in the Rapid Alert System for Food and Feed so far.
Sources :
- Pubmed
- European Union


mercredi 8 mars 2017

Seaweed : Norovirus contaminations?


Norovirus (and other waterborne viruses) can enter ocean habitat from sewage outflows or through waste discharged. Noroviruses are highly contagious. Good Aquaculturing Practice, Good Hygiene Practice, and Good manufacturing Practice are key to prevent foodborne virus outbreaks.  

Definition of Seaweed

  1. A mass or growth of marine plants
  2. A plant growing in the sea, especially: a marine alga (as a kelp)

Marine macroalgae (seaweeds) are plant-like organisms that generally live attached to hard substrata in coastal areas. They belong to three different groups :
  • brown algae
  • red algae
  • green algae

Norovirus outbreaks with seaweed

After a scientific publication by Korea describing an outbreak with seasoned green seaweed, a more recent news from Japan confirms a norovirus outbreak due to kizami nori from Japan.

1/ In South Korea, seasoned green seaweed and norovirus

In February 2012, an outbreak of gastroenteritis was reported in school A; a successive outbreak was reported at school B. A retrospective cohort study conducted in school A showed that seasoned green seaweed with radishes was significantly associated with illness. Multiple norovirus genotypes were detected in samples from students in schools A and B. Green seaweed was assumed to be linked to these outbreaks. 

2/ In Japan, kizami nori and norovirus

In February 2017, 1,098 students at the Tachikawa City schools were affected by the outbreak, linked to “Nori” 刻み海苔 dried laver seaweed (blamed for food poisoning outbreaks at schools in Tachikawa, western Tokyo, as well as Gobo and Hidakagawa, both of which are in Wakayama Prefecture).They presented with symptoms of vomiting and abdominal pain. Norovirus has been detected in at least one of the patients and the strain matched the strain found in the shredded seaweed samples.

Production of Japanese Nori.

An Example

Can Norovirus be deactivated in seaweed?

Norovirus is unique, and different from surrogates usually used in studies ( A study investigated the effects of gamma radiation (3-10 kGy) upon the inactivation of murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on the edible green and brown algae, fulvescens (Capsosiphon fulvescens) and fusiforme (Hizikia fusiforme), respectively,

Adhesion of norovirus to vegetal surfaces

The attachment of these pathogens to foodstuff and food-contact surfaces is an important mechanism in the human contamination process. The results of a study (Bacterial Surface-Displayed GII.4 Human Norovirus Capsid Proteins Bound to HBGA-Like Molecules in Romaine Lettuce) indicated that histo-blood group antigen-like molecules in LE or VE were involved in the binding of the surface-displayed HuNoV proteins to romaine lettuce.

What should seaweed producers do?

It is important that producers and processors, as well as importers and retailers of seaweed take into account the viral risk in their HACCP plan, and identify the various critical control points (CCP), where Norovirus could have been in contact with the sea vegetable. Processes should be evaluated to verify that they can inactivate norovirus, a major cause of food contamination worldwide. Good Agricultural Practice should be set into place to prevent any cross-contamination. Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 2 (Salmonella and Norovirus in leafy greens eaten raw as salads)

Norovirus Detection Methods in Seaweed

The ISO 15216 Standard, an horizontal method for the detection of foodborne viruses in food matrices, covers several specific matrices, including vegetable in a form of a leaf. Norovirus GI and norovirus GII presence or absence can be evaluated using PCR real time detecion, after several steps including sample preparation and elution. 

Learn more about Food- and Water-borne viruses

samedi 4 mars 2017

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Norovirus  detection PCR kit features

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Learn more about foorborne viruses

- Semi-Dried Tomatoes & Foodborne Virus


Persistence & Elimination of Norovirus

Find out more at

mardi 28 février 2017

Semi-dried tomatoes and foodborne virus

In February 2017, RASFF (Rapid Alert System for Food and Feed) published an alert implicating semi-dried tomatoes contaminated with norovirus. Originating from Italy, semi-dried tomatoes in sunflower oil were delivered to the Czech Republic who detected foodborne viruses (Norovirus). Both genogroups GI and GII, according to the report, were found in the samples tested.

This is unfortunately not the first time that Foodborne Viruses are to be found in Semi-dried tomatoes :

England, 2011

In October 2011, two primary cases of hepatitis A virus (HAV) infection with identical HAV genotype IB strains to those seen in other outbreaks associated with semi-dried tomatoes were reported in England. Both cases had consumed semi-dried tomatoes. Epidemiological investigations revealed 2 additional cases of genotype IB strains with different sequences who also reported having consumed semi-dried tomatoes. In November, 5 cases of HAV infection with closely related strains were identified in the Netherlands.

Netherlands, 2010

Between 31 December 2009 and 10 February 2010, 13 patients were infected by an identical hepatitis A virus strain not previously detected in the Netherlands. They had not been abroad and were widely distributed over the Netherlands. A case-control study including 12 cases and 44 controls identified semi-dried tomatoes in oil as the source of the outbreak.

France, 2010

In January 2010, two clusters of nontraveler-associated hepatitis A were reported in 3 districts of southwestern France. A single IB strain of hepatitis A virus (HAV) was isolated. An investigation was conducted to describe the outbreak, identify the vehicle of transmission and source of infection, and propose appropriate control measures. Twenty-four (51%) reported eating semidried tomatoes, 20 of 566m reported purchasing semidried tomatoes in 1 of 3 different sandwich shop chains.

Australia, 2009

A large outbreak of hepatitis A affected individuals in several Australian states in 2009. Two peaks of infection occurred, with surveillance data suggesting locally acquired infections from a widely distributed food product. The results of both case-control studies and food testing implicated the novel vehicle of semidried tomatoes as the cause of this hepatitis A outbreak. Hepatitis A RNA was detected in 22 samples of semidried tomatoes. Hepatitis A virus genotype IB was identified in 144 of 153 (94%) patients tested from 2009, and partial sequence analysis showed complete identity with an isolate found in a sample of semidried tomatoes.

Production of semi-dried tomatoes

Oven dried

Sun dried

Prevention and control of Foodborne Virus in ready-to-eat semi-dried products

Manufacturers should consider enteric viruses as a major public health risk in their Hazard Analysis and Critical Control Point (HACCP) plans, says FAO. 

Recommendations on prevention and control of HAV 

In addition to safety regulations already in place, measures need to be taken to ensure provision of virus-safe foods in order to prevent contamination. Considering the high prevalence of foodborne infections by viruses, one should exercise precaution. Proper hand hygiene should be maintained, personally and during food preparation, to prevent contamination of food and spread to other persons. Once contamination of foods has occurred, the following mitigation strategies can be employed: (i) disposal of contaminated foods; or (ii) heat treatment (at ≥ 90° C for ≥ 90 seconds and pasteurization at ≥70° C for ≥ 15 minutes). Learn More from FAO.

Persistance and eliminination of Norovirus

NoV & HAV, major vectors of food contamination 

Microbiological hazards associated with fresh produce

Viruses are not likely to grow on contaminated vegetables and fruits but can survive long enough to cause life-threatening illness in humans. Consumption of fresh and lightly processed produce, coupled with an increase in importation of produce from regions where standards for growing and handling produce may be compromised should be an incentive to producers, importers to better monitor this viral risk.


Learn more about Food- and Water-borne viruses :

jeudi 2 février 2017


The five recent RASFF (Rapid Alert System for Food and Feed) Foodborne Virus alerts in 2017 are a good reminder of the risks caused by norovirus in bivalve molluscs.

Prevalence of Foodborne Viruses in Mussels

In Southern Italy, during a two-year collecting period (2014-2015), more than 50% of the samples collected were positive to at least one foodborne virus. Norovirus represented more than 37% of the detected viruses, followed by Astrovirus, Sapovirus, Hepatitis A Virus... This study described, for the first time, the presence of aichivirus and sapovirus in mussels in Italy.

Investigation on Norovirus and HAV Presence

From January 2013 to July 2015, more than 250 samples of bivalve molluscs collected in harvesting areas from a large coastal tract of Southern Italy were screened for HAV and NoV of genogroups GI and GII. Noroviruses' RNA were identified in 14.2% of the samples with a higher prevalence for genogroup GII than genogroup GI. Matching between the NoV genotypes circulating in local population and detected in molluscs confirms the diffusion in the environment of noroviruses.

EFSA and Norovirus

Technical specifications for a European baseline survey of norovirus in oysters : The objective of the survey is to estimate the European prevalence of norovirus-contaminated oysters at production areas and batches of oysters at dispatch centres, with a 95% level of confidence and a level of precision of 5% considering an expected prevalence of 50%.

Why Norovirus like so much bivalves

Shellfish and norovirus

Freshwater and Norovirus

Contaminated water can lead to human health issues; the aims of this work were to determine the presence and identity of representative human pathogenic enteric viruses in water samples from six European countries. A 2-year survey showed that Norovirus ... and Adenoviruses were the most frequently identified enteric viruses in the sampled surface waters. The detectable presence of pathogenic viruses may represent a potential risk for human health.

Shellfish Soup and Norovirus

The aim of this study was to describe a norovirus outbreak connected to insufficient heat treatment during preparation of a shellfish soup in serving portions, during a company Christmas celebration in Norway. Consumers who want to avoid eating raw shellfish, should not assume that the shellfish tissue in preparation as described in our study is adequately heat treated.

Detection Methods for Foodborne Viruses in Bivalves

ISO/TS 15216-1:2013

describes a method for quantification of levels of HAV (Hepatitis A Virus) and NoV (Norovirus) genogroup I (GI) and II (GII) RNA, from test samples of foodstuffs or food surfaces. Following liberation of viruses from the test sample, viral RNA is then extracted by lysis with guanidine thiocyanate and adsorption on silica. Target sequences within the viral RNA are amplified and detected by real-time RT-PCR.
This approach is also relevant for detection of the target viruses on fomites, or of other human viruses in foodstuffs, on food surfaces or on fomites following appropriate validation and using target-specific primer and probe sets

ISO/TS 15216-2:2013

describes a method for qualitative detection of HAV (Hepatitis A Virus) and NoV (Norovirus) genogroups I (GI) and II (GII), from test samples of foodstuffs or food surfaces. Following liberation of viruses from the test sample, viral RNA is then extracted by lysis with guanidine thiocyanate and adsorption on silica. Target sequences within the viral RNA are amplified and detected by real-time RT-PCR.
This approach is also relevant for detection of the target viruses on fomites, or of other human viruses in foodstuffs, on food surfaces or on fomites following appropriate validation and using target-specific primer and probe sets
Sources :

lundi 3 octobre 2016

Foodborne Virus outbreaks - Latest RASFF Alerts

Bivalve molluscs (Oysters) and fruits (Raspberries) were the two latest produce implicated in the Rapid Alert System for Food and Feed; the total number of alerts is now reaching 23, above the 21 alerts from 2015.

Italy has been a strong provider of alerts, while France follows, both amounting for almost 74% of all RASFF alerts in Europe.

Foodborne viruses : not only in Europe

At the same time in the rest of the world, several outbreaks have occurred with foodborne virus contaminating :

Learn more about Food- and Water-borne viruses :

lundi 5 septembre 2016

Norovirus and Serbian raspberries

A new alert from the RASFF (Rapid Alert System for Food and Feed) for Serbian raspberries, contaminated by food-borne viruses, adds up to the 24 previous ones since 2009 for Fruits and Vegetables, originating from this country.


Norovirus and Hepatitis A Virus

Blackberries, mixed berries, raspberries have all been implicated in the past years in an information or an alert from the European authorities, following a contamination of food-borne viruses.
Serbia is not the only country of origin though (25/71 alerts for Viruses in Fruits and Vegetables), and many others have been implicated with foodborne virus contamination : Belgium, China, Poland, Chile, Morocco, Bulgaria ... according to the RASFF.

Chinese raspberries, for example, were implicated several times (4) since 2006, due to viral contamination as recently posted. This led the European community to request controls at borders for imported chinese strawberries.

Chile, also a strong raspberry Producer in the Southern Hemisphere, has been implicated in several recalls, and is now working towards better controls for a safer production of the "Chilean Frambuesas", in order to bring back confidence to the European importers.

Raspberries, a booming business for Serbia

Germany is leading the importing countries statistics in Europe with a little more than 15,000 tonnes. France had a strong increase (+16%), with 10,981 tonnes, while Austria (+78%) came 3rd with 1,851 tonnes and the UK (+34%)th  with 1,796 tonnes [Source]

Other fruits and Foodborne virus contamination

Not only are raspberries often heading the news, for virus contamination, but recent events in the US remind us that Strawberries, produced a similar way than the raspberries, can also be contaminated by foodborne viruses.

Hepatitis A Virus is the human pathogen detected in the egyptian strawberries imported into the US and used to prepare smoothies. This multistate outbreak, linked to frozen berries, has now contaminated dozens of people, mostly in Virginia.

Pomegranate arils from Turkey were also implicated in a large multistate outbreak in the US back in 2013. Hepatitis A Virus was also detected in the product, sold frozen in retail shops. 165 people were contaminated.

Water can also be a source for rapidly spreading the viruses, as recently seen in Turkey, when 32000 people were hospitalized following the consumption of water-borne virus contaminated tap water, or in Spain when more than 4000 persons got ill after drinking bottled water.

What are food-borne viruses?

  • HAV was first identified in 1973, and is a non-enveloped virus, classified within the genus hepatovirus of the picornavirus family. Hepatitis A is a liver infection caused by the Hepatitis A virus (HAV). Hepatitis A is highly contagious. HAV is  transmitted by the fecal-oral route, either through person-to-person contact orconsumption of contaminated food or water. For more information on Hepatitis A check the CDC website and WHO Website.
  • Noroviruses are highly contagious and 10-100 viral particles may be sufficient to infect an individual. They are transmitted primarily through the faecal-oral route, either by consumption of contaminated food or water, or by spreading directly from person to person. Vomiting creates aerosols with high content of virus particles, which enter the oral mucosa or contaminate surfaces. The virus survives a long time on different surfaces and thus, environment may serve as a source of new infections. For more information on norovirus check the ECDC website

Learn more about viruses