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I.L.A. Boxman
sources of viral contamination of foods were identified: (1) human sewage/feces,
(2) infected food handlers and (3) animals harboring zoonotic viruses. NoV and
HAV in prepared (ready-to-eat) foods, bivalve molluscs, and fresh produce were
selected as the virus-commodity combinations of greatest public health concern
(Anon. 2008).
For bivalve molluscs, the major route of contamination is via human fecal
contamination in growing or harvesting areas. Viruses have been observed to persist
for 8–10 weeks in contaminated live bivalve molluscs and can be detected in the
digestive tissue of bivalve molluscs (Atmar et al. 1995). Recent evidence has shown
that some NoV genotypes bind specifically to bivalve molluscs’ tissue receptor
sites, which could explain why some viruses persist after depuration procedures
as currently practiced in the industry (Le Guyader et al. 2006; Maalouf et al. 2010).
Effective control strategies need to focus on prevention of contamination as
there are currently no effective, realistic and validated risk management options
to eliminate viral contamination of both bivalve molluscs and fresh produce prior
to consumption without changing the normally desired characteristics of the food.
Therefore, the Joint FAO/WHO Food Standards Programme CCFH is working on
guidelines entitled ‘Guidelines on the application of the general principles on food
hygiene to the control of viruses in food’ (Anon. 2012).
FAO/WHO Proposed Guidelines to the Control
of Viruses in Food
The primary purpose of the new guidelines is to give guidance on how to minimize
the risk of illness arising from the presence of human enteric viruses in foods, and
more specifically from NoV and HAV in foods. The guidelines are applicable to all
foods throughout the food chain (Anon. 2012).
The guidelines should complement controls in place for any other pathogens and
should therefore be used in conjunction with the Codex Recommended International
Code of Practice – General Principles of Food Hygiene- (CAC/RCP 1-1969)
and the Code of Hygienic Practice for Precooked and Cooked Foods in Mass
Catering (CAC/RCP 39-1993), the Code of Practice for Fish and Fishery Products
(CAC/RCP 52-2003) and the Code of Hygienic Practice for Fresh Fruits and
Vegetables (CAC/RCP 53-2003).
The guidelines follow the format of the General Principles of Food Hygiene
and the main document contains nine sections. Additional recommendations for
specific virus-commodity combinations are presented in the annex on the Control
of Hepatitis A Virus (HAV) and Norovirus (NoV) in Bivalve Molluscs (Annex I) and
the annex on the Control of Hepatitis A Virus (HAV) and Norovirus (NoV) in Fresh
Produce (Annex II) (Anon. 2012). This paper summarizes the most important issues
of the draft proposed guidelines to the control of viruses in food dated December
2011 (Anon. 2011a, b) with a special focus on the control of viruses in bivalve
molluscs.
I.L.A. Boxman
sources of viral contamination of foods were identified: (1) human sewage/feces,
(2) infected food handlers and (3) animals harboring zoonotic viruses. NoV and
HAV in prepared (ready-to-eat) foods, bivalve molluscs, and fresh produce were
selected as the virus-commodity combinations of greatest public health concern
(Anon. 2008).
For bivalve molluscs, the major route of contamination is via human fecal
contamination in growing or harvesting areas. Viruses have been observed to persist
for 8–10 weeks in contaminated live bivalve molluscs and can be detected in the
digestive tissue of bivalve molluscs (Atmar et al. 1995). Recent evidence has shown
that some NoV genotypes bind specifically to bivalve molluscs’ tissue receptor
sites, which could explain why some viruses persist after depuration procedures
as currently practiced in the industry (Le Guyader et al. 2006; Maalouf et al. 2010).
Effective control strategies need to focus on prevention of contamination as
there are currently no effective, realistic and validated risk management options
to eliminate viral contamination of both bivalve molluscs and fresh produce prior
to consumption without changing the normally desired characteristics of the food.
Therefore, the Joint FAO/WHO Food Standards Programme CCFH is working on
guidelines entitled ‘Guidelines on the application of the general principles on food
hygiene to the control of viruses in food’ (Anon. 2012).
FAO/WHO Proposed Guidelines to the Control
of Viruses in Food
The primary purpose of the new guidelines is to give guidance on how to minimize
the risk of illness arising from the presence of human enteric viruses in foods, and
more specifically from NoV and HAV in foods. The guidelines are applicable to all
foods throughout the food chain (Anon. 2012).
The guidelines should complement controls in place for any other pathogens and
should therefore be used in conjunction with the Codex Recommended International
Code of Practice – General Principles of Food Hygiene- (CAC/RCP 1-1969)
and the Code of Hygienic Practice for Precooked and Cooked Foods in Mass
Catering (CAC/RCP 39-1993), the Code of Practice for Fish and Fishery Products
(CAC/RCP 52-2003) and the Code of Hygienic Practice for Fresh Fruits and
Vegetables (CAC/RCP 53-2003).
The guidelines follow the format of the General Principles of Food Hygiene
and the main document contains nine sections. Additional recommendations for
specific virus-commodity combinations are presented in the annex on the Control
of Hepatitis A Virus (HAV) and Norovirus (NoV) in Bivalve Molluscs (Annex I) and
the annex on the Control of Hepatitis A Virus (HAV) and Norovirus (NoV) in Fresh
Produce (Annex II) (Anon. 2012). This paper summarizes the most important issues
of the draft proposed guidelines to the control of viruses in food dated December
2011 (Anon. 2011a, b) with a special focus on the control of viruses in bivalve
molluscs.