Foodborne viruses: an emerging problem

Abstract

Several groups of viruses may infect persons after ingestion and then are shed via stool. Of these, the norovirus (NoV) and hepatitis A virus (HAV) are currently recognised as the most important human foodborne pathogens with regard to the number of outbreaks and people affected in the Western world. NoV and HAV are highly infectious and may lead to widespread outbreaks. The clinical manifestation of NoV infection, however, is relatively mild. Asymptomatic infections are common and may contribute to the spread of the infection. Introduction of NoV in a community or population (a seeding event) may be followed by additional spread because of the highly infectious nature of NoV, resulting in a great number of secondary infections (50% of contacts). Hepatitis A is an increasing problem because of the decrease in immunity of populations in countries with high standards of hygiene. Molecular-based methods can detect viruses in shellfish but are not yet available for other foods. The applicability of the methods currently available for monitoring foods for viral contamination is unknown. No consistent correlation has been found between the presence of indicator microorganisms (i.e. bacteriophages, E. coli) and viruses. NoV and HAV are highly infectious and exhibit variable levels of resistance to heat and disinfection agents. However, they are both inactivated at 100 degrees C. No validated model virus or model system is available for studies of inactivation of NoV, although investigations could make use of structurally similar viruses (i.e. canine and feline caliciviruses). In the absence of a model virus or model system, food safety guidelines need to be based on studies that have been performed with the most resistant enteric RNA viruses (i.e. HAV, for which a model system does exist) and also with bacteriophages (for water). Most documented foodborne viral outbreaks can be traced to food that has been manually handled by an infected foodhandler, rather than to industrially processed foods. The viral contamination of food can occur anywhere in the process from farm to fork, but most foodborne viral infections can be traced back to infected persons who handle food that is not heated or otherwise treated afterwards. Therefore, emphasis should be on stringent personal hygiene during preparation. If viruses are present in food preprocessing, residual viral infectivity may be present after some industrial processes. Therefore, it is key that sufficient attention be given to good agriculture practice (GAP) and good manufacturing practice (GMP) to avoid introduction of viruses onto the raw material and into the food-manufacturing environment, and to HACCP to assure adequate management of (control over) viruses present during the manufacturing process. If viruses are present in foods after processing, they remain infectious in most circumstances and in most foods for several days or weeks, especially if kept cooled (at 4 degrees C). Therefore, emphasis should be on stringent personal hygiene during preparation. For the cont...

Genotypes of rotavirus associated with acute gastroenteritis in Seoul, Korea

“…Genotype P [8] was detected in 148 cases (55%) while P [6] was detected in 57 cases (21.2%) and P [4] in 29 cases (10.8%). The rare genotypes P [9] and P [10] were detected in three samples ( In total, 25 G and P combinations were identified. G1P [8] the most frequently detected strain, responsible for 38.3% of infections.…”

Foodborne zoonoses due to meat: a quantitative approach for a comparative risk assessment applied to pig slaughtering in Europe

“…Information regarding the prevalence rates for hazards on pork carcasses and the occurrence of the clinical disease they induce in humans is needed to assess risks due to pork consumption. However, although many hazards have a huge impact on public health, such information is not available, mainly because of the cost and difficulties of detection of these hazards in food, as for Clostridium botulinum or viral hazards [10,13]. Moreover, even when enough information is available to calculate mean rates of prevalence or incidence, and when it is obtained with sensitive and efficient methods, the range of available values is often wide.…”

Analytical Methods for Virus Detection in Water and Food

“…Transmission of viruses associated with the consumption of contaminated bivalve shellfish, particularly, oysters which are eaten uncooked, is regularly reported (Koopmans and Duizer 2004;Widdowson et al 2005). Other foods, including raspberries (Cotterelle et al 2005;Le Guyader et al 2004;Gaulin et al 1999;Korsager et al 2005;Hedlund et al 2000;Falkenhorst et al 2005;Hjertqvist et al 2006;Fell et al 2007;Ponka et al 1999) and salads (Vivancos et al 2009), have caused outbreaks after being contaminated by polluted water or virus-infected food handlers.…”