Ad Hoc Group on Foodborne Viral Infections meeting 12 July 2011

Summary of the fourth meeting of the ad hoc group on Foodborne Viral Infections

1. Introduction

At this meeting the group considered the microbiological impact of sewage discharges on shellfisheries and were briefed on the work of the Cleaner Seas Forum.

2. Sewage discharges and their impact on shellfisheries

Members received a presentation on sewage discharges, their microbiological impact on shellfisheries and control options. The presentation revealed the pressures on coastal water quality which includes population pressure in coastal areas, discharges to coastal waters (over 2000 discharges of land origin occur yearly) and the legacy of combined sewage system (CSOs). The treatment regime for discharges was outlined.

Members were informed about the Centre for Environment, Fisheries and Aquaculture Science integrated shellfish hygiene system that incorporates a database on discharges. The system holds information on location of shellfisheries and helps in the provision of response to emergency discharges.

An overview of various legislation relevant to the Government’s water quality policy was provided. Members also received an explanation of the rules under the European Hygiene Regulations (852-4/2004) which required the identification and classification of shellfish production areas. This is based on time series assessment of bacterial indicator (E. coli) data. Shellfish beds are classified A, B, C (or prohibited).

The issue of intermittent discharges was discussed. It was acknowledged that there are many intermittent discharges impacting upon shellfisheries and that rain related storm overflows are difficult to manage.

On sewage discharges and control options, members were informed of the current pro-active measures which include further improvement of some sewage treatment works and extending requirements for monitoring (of sewer overflows). Reactive options include: suspension of harvesting (with specification for duration), additional post harvesting treatment (Shellfish Association of Great Britain booklet on cooking of oysters, extended depuration, and different temperature for depuration) and product testing. For future considerations, some water quality considerations were highlighted including additional sewage treatment measures, improved monitoring, revising standards, improved epidemiological evidence and longer term investment/ planning.

3. Cleaner Seas Forum

Defra briefed the group on the work of the Cleaner Seas Forum (CSF) a Defra Ministerial-led group of stakeholders with an interest in tackling microbial pollution in coastal waters, in particular bathing and shellfish waters. CSF aims to build on the existing regulatory work with partners taking voluntary action to improve water quality and information exchange.

For the first time real-time warnings of CSO spills at bathing waters are now in place in some parts of the UK which demonstrates the relationship between surfers, LAs and water companies. In 2010, the CSF helped develop a Bathing Water Pilot project in Cornwall to examine the viability of giving more 'real-time' information on overflows from the sewerage. In 2011 this pilot scheme extended to 49 bathing waters.

Members discussed the issue of co-operation between water companies, LAs and shellfish farmers/harvesters in relation to the risk of spills to public health.

The group highlighted the huge gap on norovirus data in the population (no data on the number of people that fall ill from norovirus) and the complexity in carrying out risk assessment. The group agreed that the EFSA subgroup report on foodborne viral infection which was due to be published in summer 2011 would be useful material for members to consider.

4. Work Programme

The group reviewed its work programme and it was highlighted that:

  • At the September meeting 2 EHOs would be attending to brief the group on how they prioritise norovirus and deal with complaints from consumers
  • At the October/November meeting the results of FSA-funded project on the prevalence, distribution and levels of norovirus in oyster harvesting areas in the UK and VITAL project should be available for consideration
  • The Secretariat should arrange for an appropriate person to brief the group on norovirus on food contact surface contamination