ACMSF minutes: 17 March 2005

The 55th meeting of the Advisory Committee on the Microbiological Safety of Food was held at 10.30 am on Thursday 17 March 2005 in Aviation House, 125 Kingsway, London WC2B 6NH. This meeting was open to members of the public.


Professor B Reilly

Mr J Bassett
Dr D Brown
Ms S Davies
Professor T Humphrey
Mr A Kyriakides
Ms E Lewis
Mr P Mepham
Mr B Peirce
Mr D Piccaver
Professor L Piddock
Dr Q Sandifer

Mr H Baillie (Defra)
Dr J Hilton (FSA)
Dr S Neill (DARDNI)

Dr L Foster (Administrative Secretary)
Ms G Hoad (Acting Scientific Secretary)
Mrs E Stretton
Ms S Butler

Dr S Stringer (IFR): agenda item 6
Dr C Pin (IFR): agenda item 6
Dr I Gillespie (HPA): agenda item 7
Mrs M Howell (FSA): agenda item 9
Members of the public: see Annex I

1. Chairman's introduction

1.1 The Chairman welcomed ACMSF Members and members of the public to the 55th meeting of the Committee.

1.2 The Chairman also welcomed Dr Sandra Stringer and Dr Carmen Pin (both from the Institute of Food Research), Dr Iain Gillespie (HPA) and Mrs Mary Howell (FSA) who would be presenting agenda items 6, 7 and 9 respectively.

1.3 The Chairman asked Members to identify any items for discussion under any other business at the end of the meeting. There were none.

2 Apologies for absence

2.1 Apologies for absence were received from Mr Paul Gayford (Defra Departmental Assessor), Dr Paul Cook (Scientific Secretary), Dr L Doherty (NIDHSSPS; Departmental Assessor), Mr Paul McMullin, Professor Paul Hunter, Professor Peter Williams, Professor Sarah O'Brien, Professor Mike Gasson and Dr Kay Hadley.

3 Declarations of interests

3.1 The Chairman reminded the Committee of the need to declare any conflicts of interests relating to items on the agenda. Mr Kyriakides reported, in connection with agenda item 6, that Sainsbury's was working on reducing product salt levels. Similarly, Mr Bassett reported that Unilever was also involved in salt reduction work (agenda item 6). Mr Piccaver added that as a producer, he had an interest in ready-to-eat fruit and vegetables (agenda item 7). In connection with agenda item 8, the Chairman reported that he was a member of the Defra Antimicrobial Resistance Group.

4 Minutes of the 54th meeting (ACM/MIN/54)

4.1 Members approved ACM/MIN/54 as a correct record of the previous meeting subject to one minor amendment to insert 'and asked how the FSA was dealing with the issues raised', to the end of the first sentence in paragraph 14.1. The Secretariat was asked to arrange for these final minutes to be posted on the Committee's website.
Action: Secretariat

5 Matters arising

5.1 The Chairman drew attention to the Secretariat information paper ACM/727 detailing matters arising from previous meetings. In relation to paper ACM/MIN/54 paragraph 8.4, Mr Kyriakides queried whether the Committee would still have sight of the scope of the independent review of scientific evidence in relation to the shelf life of MAP/VP foods prior to the review being commissioned. The Chairman confirmed the scope would be circulated to the Committee once it became available and requested that the Secretariat append a tracking list of action points to all future matters arising papers.
Action: Secretariat

5.2 There were no other matters arising identified by members of the Committee.

6 Salt reduction: impact on food safety

6.1 At the Chairman's invitation Ms Hoad introduced agenda item 6, which comprised a presentation by Dr Sandra Stringer and Dr Carmen Pin from the Institute of Food Research. She informed Members that the FSA had commissioned the Institute of Food Research to carry out a review of the microbiological risks associated with salt and nitrite/nitrate reduction in certain foods and alternatives for preservation, particularly in relation to Clostridium botulinum. The review was being undertaken so that the FSA could have clear evidence regarding the role of salt and nitrate/nitrite in the control of the safety of certain products, particularly cured meats, and to provide information for small manufacturers reducing levels of salt in these products to enable them to do so safely.

6.2 Dr Stringer outlined the scope of the review, microbiological considerations of reducing salt, conditions for growth of non-proteolytic Clostridium botulinum, alternative methods of preservation and use of predictive models. Dr Pin outlined modelling applications based on using the z-value for growth.

6.3 In the ensuing discussion of the paper, a number of points were made:

  • Members questioned the timing of the review in relation to the fact that the FSA had already communicated its targets to reduce salt in the diet. However, Members considered that the strategy on salt reduction was sound, and that its delivery should be supported by the scientific work to understand and manage the microbiological risks. In response, Ms Hoad pointed out that the Agency had not in fact set targets for individual foods. The salt model constituted a basis for discussions with industry.
  • Some concern was expressed relating to the communication and awareness of salt reduction messages to small producers. Members queried how small producers would make practical use of FSA information on salt reduction while ensuring products with modified salt levels were microbiologically safe. Members suggested products should not be reformulated with lower salt levels until a hazard analysis had been carried out.
  • Practical guidance to small manufacturers on salt reduction should be produced and communications with smaller producers should be examined to ensure formulation changes did not result in microbiological safety being compromised. Ms Hoad replied that it was the FSA's intention to provide guidance for small producers following the review.
  • Salt reduction may adversely affect product quality resulting in increased spoilage and product wastage. The impact of salt reduction on product shelf life should be considered as part of the review.
  • Members queried the focus of the food groups under review suggesting that work should focus on only those food groups which contribute significant salt intake to the diet (e.g. processed meals), and identify those foods where salt reduction would have the greatest effect. It was pointed out that bacon and ham made a significant contribution to dietary salt intake.
  • Relevant models and available research should be examined, and any shortfalls identified. There was a requirement to ensure microbiological risk to foods as a result of salt reduction was clearly identified.

6.4 The Chairman thanked Dr Stringer and Dr Pin for their presentation and requested that Members revisit this issue to consider the results of the review following its completion in due course.

7 Microbiological status of ready-to-eat fruit and vegetables (ACM/729)

7.1 At the Chairman's invitation Mr Gillespie (HPA) introduced paper ACM/729 which updated Members of the microbiological status of ready-to-eat fruit and vegetables.

7.2 Mr Gillespie outlined data relating to general and foodborne related outbreaks of infectious intestinal disease, and foodborne outbreaks associated with consumption of salads, vegetables or fruit between 1992-2003. He also updated Members on two recent outbreaks of Salmonella infection associated with the consumption of lettuce.

7.3 Members reviewed Table 2 of the paper, pointing out that it was difficult to identify ready-to-eat salad components. Mr Gillespie agreed to supply an addendum which extracted details relating to which food contained components of rready-to-eat salads.
Action: Ian Gillespie

7.4 Members discussed outbreaks linked to ready to eat salads noting that a large proportion of the outbreaks were linked to commercial catering establishments, whereas outbreaks linked to salad consumption in the home were less frequent. Members noted that pre-packed ready-to-eat salads were subject to stringent raw material and washing controls, and queried whether the same controls applied to whole lettuce and salads in catering outlets.

7.5 Mr Gillespie informed Members that outbreak investigations were not always able to collect enough information to enable identification of the food or ingredient vehicle for infection, or to establish the origin of the vehicle. He confirmed that the Health Protection Agency had carried out an examination of investigations of infectious intestinal disease, and these findings had been published. With regard to the origin of food outbreak vehicles (imported foods), he explained that, in order to ensure completion at a local level, the standard outbreak questionnaire was concise, therefore collected information was limited. He added that HPA had developed an enhanced surveillance programme to examine salmonella in non-UK eggs, and programmes had been put in place to examine outbreak investigations. He stressed that HPA's main priority was to control an outbreak and not necessarily to find the origin of the source.

7.6 Mr Piccaver commented that it was important to report information on outbreaks, and also to state the origin of material in any reporting procedure. He added that as ready-to-eat salads were seasonal crops, these products were often imported from other countries at different times of the year, thus the origin of such products was significant in any outbreak investigation. Dr Hilton commented that, from recent experience, the ability to trace back products depended on when HPA Centre for Infections and the FSA became involved in an outbreak investigation. She added that, in relation to the recent outbreaks associated with lettuce, the FSA was waiting for a response from Spain in relation to its investigations of lettuce growers that may have supplied product associated with the outbreaks.

7.7 The Chairman thanked Mr Gillespie for his presentation. In summing up he requested that the FSA consider developing the production of guidance for caterers on the handling and preparation of salads. He also requested that the FSA consider ways to improve data quality on the contamination of salads. Finally, the Chairman requested that the HPA provide more detailed information comparing outbreaks associated with fruit and vegetables in the raw state with those where these ingredients were part of a cooked meal.
Action: Secretariat, Mr Gillespie (HPA)

8 Report from the Defra Antimicrobial Resistance Co-ordination Group (DARC) (ACM/730)

8.1 In the absence of the DARC Chairman (Dr Fitzgerald), the Chairman informed Members that the ACMSF Report on Microbial Antibiotic Resistance made a series of Government recommendations. The DARC Group paper set out the work that had been carried out to meet these recommendations to inform the Committee of the actions taken. Key areas of work carried out included the undertaking of surveys on prevalence, sub-type and antibiotic resistance of foodborne pathogens; harmonisation of ring trials on antibiotic resistance methods to identify any differences in methods; publication of a strategy for developing and implementation of a programme of surveillance for antibiotic resistance in animals in England and Wales; development of an overarching Antibiotic Resistance report for the UK; publication of annual veterinary sales data and Government-funded research.

8.2 Professor Piddock queried which Government recommendations had not been carried forward by the DARC Group. The Chairman confirmed that DARC's remit was to consider animal-based recommendations only. In response to a point regarding the illegal sales of antibiotics, the Chairman informed Members that VMD were collecting data on sales of antibiotics, although information on their use was not available. The report did not address illegal sales of antibiotics. However, this area was becoming increasingly policed, and new legislation proposed under the Veterinary Medicines Directive was likely to impact on illegal sales.

8.3 In summing up, the Chairman confirmed the Committee was content to accept the DARC Report. However he requested that a summary of progress on all the recommendations (not just those covered in the DARC Report) should be provided.
Action: Secretariat

9 Antimicrobial treatment (decontamination) of poultry meat (ACM/731)

9.1 At the Chairman's invitation, Mrs Howell (FSA) presented paper ACM/731, outlining a draft Commission regulation laying down specific conditions for antimicrobial treatment of food of animal origin.

9.2 Mrs Howell outlined the conditions of use for antimicrobial treatment of food of animal origin and permitted products listed for use on poultry in the draft regulation. She reviewed the benefits and disadvantages associated with the proposed use of chemical decontamination of meat, and outlined the FSA's position on the draft regulation for Member's consideration.

9.3 In the ensuing discussion of the paper, Members raised the following points:

  • The ACMSF's second report on campylobacter reported a Danish risk assessment concluding that a reduction in the number of campylobacter on a carcass would be associated with a significant reduction in illness. Therefore, antimicrobial treatments could have a potential benefit.
  • Members agreed that the need to label antimicrobial treatments was questionable as these substances were intended as processing aids. Members noted that there may be benefits associated with controlled use of some antimicrobial treatments. However, reservations were expressed if these processing aids were to be introduced on a widespread basis.
  • Some concern was expressed that antimicrobial treatments may be used in preference to adoption of food hygiene controls and initiatives. Members noted that such treatments would be permitted for use only within the context of HACCP.
  • The impact of antimicrobial treatment on reduction of pathogen levels was discussed and it was noted that little published information was available.

9.4 Members supported the FSA view that:

  • the draft regulation was premature, and that where appropriate more work was needed on the use of proposed antimicrobial decontamination treatments before their use was approved
  • the SCVPH opinion was inadequate in terms of toxicological assessment
  • a risk assessment as proposed by Codex was needed to consider potential food safety benefits in the context of any possible toxicity
  • adoption of the proposal could adversely affect efforts to promote hygiene measures
  • consumer concerns about the use of these treatments and requirements for labelling were unknown

9.5 Members recommended that the FSA carried out research to explore consumer views on the use of antimicriobial treatments, including labelling. The Committee also suggested a risk assessment should be considered.

10. Committee sub-groups

Infant botulism

10.1 At the Chairman's invitation, in the absence of Professor O'Brien, Mr Kyriakides informed Members that a further meeting of the Group had taken place on 28 January. A report of the Group's deliberations had been drafted of which risk profile modelling work formed a key part. He explained that at this meeting some inconsistencies had been identified between model outputs and evidence in the literature, and these were currently being investigated further. Following peer review of the risk work, it was anticipated that the report would be presented to the June meeting of the Committee.

Botulism in cattle

10.2 The Chairman informed Members that three meetings of this group had taken place to date. The last meeting had been held on 17 February. At this meeting the group heard further evidence from the Department of Agriculture and Rural Development in Northern Ireland on botulism mouse bioassay testing, vaccination and outbreak management. The group also reviewed geographical mapping information of outbreaks in England and Wales. A detailed discussion of contributions for the preliminary draft of the report also took place. A further meeting of the group was scheduled for 21 March. At this meeting further evidence requested by the group would be reviewed, and revisions to the draft report would be discussed. In the intervening period, work on drafting the report would continue. It was anticipated that the group would present the outcome of its deliberations to the committee at the June ACMSF meeting.

Imported Foods

10.3 At the Chairman's invitation, Mr Mepham presented paper ACM/732, an interim report on the work of the group, to the committee. He outlined the terms of reference and background to the issues being considered by the group including controls of foods of non-animal origin, traceability, outbreaks of foodborne illness and bush meat. He informed the committee that a further report would be provided once the group had completed its consideration of the review of bush meat currently being undertaken on behalf of the Food Standards Agency. A further meeting of the group was scheduled for the autumn.

Newly-emerging pathogens

10.4 At the Chairman's invitation, in the absence of Professor Hunter, Lucy Foster informed the committee that the message board had now been set up, and that most Members had registered. A mechanism had also been put in place to alert Members to discussion items on the message board. She encouraged Members to make active use of the message board for discussion of emerging issues.

10.5 The Chairman thanked all the chairs of the sub groups for their contributions.

11 Epidemiology of Foodborne Infections Group (EFIG)

11.1 At the Chairman's invitation Dr Hilton updated the Committee on the outcome of the meeting of EFIG which took place on 17 January.

11.2 By way of introduction, Dr Hilton explained that EFIG was set up in the mid 1990's to fulfil a function previously carried out by a sub-Group of the ACMSF, thus bringing together consideration of animal and human epidemiological data. At its most recent meeting, the Group had also considered food surveillance.

11.3 She informed Members that the group had considered animal data noting that, in general, 2004 was a relatively quiet year with the number of salmonella reports from all species, except horses and ducks, showing a decrease. The main serotypes found in animals were consistent from year to year. One new serovar was reported as emerging in cattle (S. London). The group noted a report of extended spectrum beta-lactamase producing E.coli in cattle. Details of the survey of cattle, sheep and pigs at slaughter, which had been published in November 2004, were also discussed. In terms of human data, the group discussed Salmonella enteritidis non-PT4 related outbreaks associated with eggs in England and Wales, noting Salmonella enteritidis figures for 2004 were lower than those for 2003. Levels of campylobacter also continued to decline in 2004 (observed across several countries). The incidence of foodborne disease associated with E.coli O157 remained relatively constant in 2004 (slight increase observed). Outbreaks associated with foodborne pathogens in 2004 were also discussed.

11.4 Dr Hilton reported that the group also discussed development of an enhanced surveillance system for monitoring listeria data, following the doubling of cases in 2003 and 2004. HPA/LACORS were also conducting sandwich and butter surveys, as these foods were linked to previous outbreaks of listeria.

11.5 The EFIG Group was updated on developments to commission a follow-up study of infectious intestinal disease, which would focus on prevalence and would not include the risk factor questionnaires included in the previous study. Other issues discussed included Johnes Disease and MAP, and the shift in approach from surveys to rolling surveillance of food. Finally the group received brief update reports on the incidence of salmonella associated with foreign travel, and forthcoming surveillance of eggs and laying flocks.

11.6 Members discussed outbreaks of salmonella associated with non-UK eggs. She also confirmed that the current incidence of salmonella was low, noting that the purchase of Spanish eggs had dropped and purchase of UK-produced eggs had increased. She mentioned that a report on the implementation of a control plan for reducing prevalence of salmonella in laying flocks from Spain was anticipated. Dr Hilton confirmed that there were no changes in the prevalence of different serovars in animals, with the exception of Salmonella London.

11.7 Members discussed the impact of the reduction in HPA funding on the availability of surveillance and epidemiological data. Dr Hilton confirmed that the respective Chief Executives of the FSA and HPA met regularly and this issue could be raised at one of these meetings.
Action: FSA

11.8 Members shared some concern following reports of the doubling of laboratory reported cases associated with listeria reported in 2003 and 2004, querying where the increase in listeriosis originated from. Dr Hilton agreed to report back to the Committee with further information.
Action: FSA

12 Dates of future meetings (ACM/717)

12.1 The Chairman brought to Members' attention paper ACM/733 which listed the dates for ACMSF meetings in 2005.

13. Any other business

13.1 Ms Lewis suggested the committee should consider avian influenza at a future meeting. The chair replied that there were several other groups looking at the risks associated with transfer of avian influenza from birds to humans. Mr Kyriakides pointed out that, at a previous ACMSF meeting, Dr Brown had agreed to keep a watching brief on this issue on behalf of the committee.

13.2 The Chairman informed Members that Mr Brian Peirce and Mr David Piccaver's periods of appointment ended on 31 March. He thanked both Members for their personal commitment and contribution to the work of the Committee.

14. Public questions and answers

14.1 The Chairman invited the members of the public present to ask any questions they might have on the work of the Committee, or to make any observations.

14.2 Mr Alan Long (VEGA Research) raised several issues including the use of illegal antibiotics by farmers in the dairy industry (referring to information on the VEGA website), standards for animal welfare and publication of a letter in the Veterinary Record on extended-spectrum beta-lactamase detected in E. coli recovered from calves in Wales (ACM/734). The Chairman confirmed that the ACMSF did not condone any illegal antibiotic sales, and that new legislative measures were being put in place to ensure correct use of antibiotics. He added that welfare issues were being addressed under Defra's Animal Health and Welfare Strategy.

14.3 Ms Kaarin Goodburn (Chilled Foods Association) referred to the Committee's recommendation for guidance on the washing of salads, reiterating the need for clarity in the communication of information following outbreaks of foodborne disease associated with imported lettuces. She added that decontamination controls for ready-to-eat bagged salads were different from those for other salads. She also queried how traceability issues were being addressed by the ad hoc Group on Imported Foods. In addition, in relation to the vacuum-packing guidance discussed at the December 2004 meeting, she pointed out that the French had not endorsed the proposal for a 90°C for 10 minutes 10 day shelf life, based on scientific data, which they had been unwilling or unable to supply. She requested that the FSA assist in obtaining sight of this data. Finally she queried whether the Freedom of Information Act would permit access to Rapid Alert System for Food and Feed (RASFF) notifications and alerts.

14.4 The Chairman confirmed that the FSA was currently working to commission an independent review of the scientific evidence supporting the vacuum-packing guidance proposals discussed at the last meeting. He requested that the FSA explore whether the French scientific data was available.
Action: FSA

14.5 Dr Hilton explained that with regard to Freedom of Information Act and access to the RASFF system, anyone was free to put an application in writing under the Act requesting information. However, she pointed out that RASFF was a confidential European system which may be subject to exemptions under the Act.

14.6 The Chairman acknowledged that the routes of supply of salads to caterers were different from those for pre-washed bagged lettuce. Dr Hilton confirmed that a very strong evidence-based case needed to be provided to restrict UK trade in products from other Member States, as such decisions required endorsement on a European basis.

14.7 Mr Tom Miller (Food Regulatory Affairs consultant) clarified his comments in the minutes of the last meeting (paper ACM/MIN/54, paragraph 15.2). He explained that his concerns related to the direct risk of contamination associated with an individual breaking out eggs while handling other foods at the same time. In relation to the proposal to develop guidance for caterers on washing salads, he commented that most caterers washed salads to remove dirt only. Any guidance would need to be carefully framed so as not to convey the impression that salads were unsafe to eat.

14.8 Mr Richard Wood (BRC) queried what discussion had taken place between the FSA's Microbiological Safety and Nutrition Divisions on the design of the salt model. He also queried the basis for assuming levels of salt in products on the market guaranteed their safety. Ms Hoad replied that the target average values in the model were based on levels of salt present in products on the market. It was emphasised that the salt model was only an example of how reductions could be made to achieve the FSA target of an average salt intake of 6g/day. She added that responsibility to produce microbiologically safe food lay with the manufacturer.

14.9 Dr Lyndon Davies (IFST) commented that the Committee's concerns relating to the use of antimicrobial treatments to clean up food were reminiscent of the 1980s when it was proposed that irradiation should be used to disinfect certain foods. He stressed the need for tight regulation of any antimicrobial treatments used, and supported the need for consumer research on this issue.

15. There being no further business, the Chairman thanked Members and members of the public for attending and closed the meeting.