Professor Sarah O’Brien
Professor Bob Adak
Dr Gary Barker
Mr John Bassett
Dr Roy Betts
Mrs Vivianne Buller
Professor John Coia
Mrs Rosie Glazebrook
Professor Rick Holliman
Ms Jenny Hopwood
Professor David McDowell
Mr Paul McMullin
Dr Sally Millership
Mrs Jenny Morris
Mr David Nuttall
Ex officio member: Mrs Joy Dobbs (SSRC)
Mr Javier Dominguez (FSA)
Mr Stephen Wyllie (Defra)
Dr Paul Cook (Scientific Secretary)
Ms Geraldine Hoad (Administrative Secretary)
Mr Adekunle Adeoye
Miss Sarah Butler
Members of the public:
Fiona Brookes, 2 Sisters
Bridgette Clarke, Bakkavor
Catherine Cockcroft, Exova
Alistair Gault, Avondale Foods
Kaarin Goodburn, Chilled Food Association
Linda Gordon, Safefood
Dr Claire Jenkins, PHE
Intisar Khan, Dairy Crest
John Lawler, Public Health England
Alan Lyne, ADAS
Eilis McCormick, Avondale Foods
Dr Helen Payne, Leatherhead Food International
Rick Pendrous, Food Manufacture magazine
Eric Samuels, Pall Life Sciences
Karen Sims, Waitrose
Yvonne Stedman, Mars
Sian Thomas, Fresh Produce
Andrew Walker, Premier Foods
Elizabeth Williamson, Sainsburys
Nicola Wilson, Westward Laboratories
1. Chair’s introduction
1.1. The Chair welcomed ACMSF Members and members of the public to the Committee’s 82nd meeting. She also welcomed Dr Kirsty Foster, Consultant in Health Protection from the Public Health England Centre North East, Dr Russell Gorton, Consultant Epidemiologist, Public Health England, who would be presenting the findings of the Street Spice outbreak (agenda item 9) and also Paula Davies, Food Safety Team Manager, Newcastle City Council and Dr Claire Jenkins, PHE Gastrointestinal Bacteria Reference Unit who were attending to support the discussion on item 9.
1.2. The Chair also welcomed Mrs Joy Dobbs, Deputy Chair of the Social Science Research Committee who would be providing a link between the two committees, and Mr Javier Dominguez who was representing the Food Standards Agency (FSA) in place of Ms Liz Redmond.
1.3. The Chair informed the committee that Dr Sophie Rollinson had left the FSA to take up a new post in Defra and she thanked her for her excellent support as part of the scientific secretariat over a number of years.
1.4. Finally, the Chair congratulated Professor Adak on the attainment of his honorary chair.
2. Apologies for absence
2.1. Apologies for absence were received from Professor Jim Gray, and from Mrs Ruth Parry, Department of Health representative.
3. Declaration of interests
3.1. The Chair reminded Members of the need to declare any conflicts of interest relating to items on the agenda. Professor Coia declared that he provided consultancy advice to Tesco.
4. Minutes of the 81st meeting (ACM/MIN/81)
4.1.1 Members asked for the following amendments to be made to the minutes: Page 3: in the last sentence of paragraph 6.2 the figure in brackets should be 63°C;
4.1.2 Page 6: amend last sentence of paragraph 7.2 to read “it is not clear that this is always the case”;
4.1.3 Page 10: in paragraph 12.3 the Consumer Advisory Committee should properly be referred to as the Consumer Advisory Panel.
4.2 Apart from these amendments the Committee agreed the minutes could be posted on the ACMSF website as a correct record of the previous meeting.
5. Matters arising (ACM/1133)
5.1 Ms Hoad drew Members’ attention to the summary of actions taken on matters arising from the last meeting. There were 3 items where work was still in progress:
5.1.1 The report on raw, rare and low temperature cooked foods which would be completed very soon.
5.1.2 The risk assessment on Mycobacterium bovis in meat which was being restructured and would be re-submitted to the Committee at a future meeting.
5.1.3 A presentation on the work of the FSA research on domestic kitchen practices was being arranged for a future meeting.
6. Update on viruses in the food chain (ACM/1134)
6.1 The Chair reminded Members that when the report had been discussed at the last meeting on 3 October, the expectation was that it would be finalised and sent out for consultation in November 2013. However, it had not been possible to keep to this timetable. One reason for this was that it might have been possible to include information from the Defra pig survey, but the publication of this had been postponed which meant that the data was not yet in the public domain and so could not be included in the ACMSF report. Further work on prioritisation of the recommendations had been carried out and the Chair explained that these had been grouped into 2 categories: those which related to risk assessment, and those that would have an impact on risk management.
6.2 In the absence of any further comments from Members on the revised draft report, the Chair asked that the public consultation should commence as soon as possible. The final draft of the report, including any amendments made as a result of the consultation, would return to the Committee in June, before being submitted to the FSA.
7. Listeriosis in England and Wales (ACM/1135)
7.1 Prof Bob Adak was invited to present paper ACM/1135 (Epidemiology of listeriosis in England and Wales between 2008 and 2013). He reported that nothing much has changed in the last few years (3 years) in relation to the number of listeriosis cases in England and Wales. Members were informed that a total of 1017 cases were reported to the enhanced Listeria surveillance system between 2008 and 2013. 12.7% of the cases were pregnancy related cases.
7.2 The number of non-sporadic and non-pregnancy associated cases from 2008 to 2013 were approximately 150 cases per year. From 2008 to 2013, 17 outbreaks/clusters were investigated involving a total of 83 cases with few cases in 2013. It was highlighted that because of the characteristics of listeriosis outbreaks, regardless of what year clusters are investigated, cases tend to span across several years. A cluster or outbreak identified and investigated in 2013 may include cases from 2008 and 2009 that were previously thought to be sporadic.
7.3 Prof Adak explained that a high proportion of cases are in the older age group and these are mostly those who have underlying medical conditions. It was pointed out that although there were no obvious regional differences in listeriosis, the North East has the highest rate of listeriosis when compared with other regions in England and Wales in the reporting period 2008 to 2013.
8. Relative risk ranking of ready-to-eat foods for vulnerable groups (ACM/1136)
8.1 Dr Paul Cook introduced this paper. He reminded Members that the FSA, as part of its strategic plan, had indicated the need to tackle those pathogens which contribute most cases or deaths to the burden of foodborne disease. Whilst Campylobacter was responsible for most cases, Listeria monocytogenes was important in terms of the number of deaths. The FSA has developed a Listeria risk management programme which has 3 strands: consumer focussed activities; procurement/provision of foodstuffs; and industry compliance/enforcement.
8.2 He mentioned that following a rise in listeriosis in recent years (10 years), the FSA had issued advice to vulnerable groups about avoiding certain foods and similar advice had been issued in other countries (as detailed in the ACMSF report on the increased incidence of listeriosis published in 2007). Before issuing any further advice, as part of the consumer workstream, the FSA wanted to have robust, evidence-based information to be able to rank the relative risk associated with a variety of ready-to-eat foods.
8.3 Dr Cook outlined 2 approaches to risk ranking, described in paper ACM/1136: using a statistical source attribution model, and using collated data from food surveillance studies, incidents reported to the FSA, and general outbreaks of listeriosis. The paper compared these approaches. Dr Cook pointed out a number of caveats in considering the rankings: the timespans for the data sources were not the same, and the way foods were categorised varied between studies. However, even taking these into account there was some correlation between the 2 approaches in terms of the main food categories associated with listeriosis, with ready-to-eat meats, pre-packed sandwiches and prepared salads (composite foods) and fish and shellfish being the main categories.
8.4 The Chair asked Members for their comments on the approach and outcome of the ranking exercise and whether they considered the information gained was sufficiently robust for the FSA to use in its risk management programme.
8.5 Members expressed caution in treating the results as robust evidence due to a number of factors, including:
- varying ways of categorising food items. In foodborne outbreaks it was difficult to pinpoint the exact source but this could often be attributed to a dish rather than individual ingredients, hence the use of the term “multi-component products.” It was noted that the description “prepared salads” covers a very large area which could be just green leafy vegetables or those containing various sorts of protein;
- people’s behaviour changes at various points in their life, e.g. women may change their diet when pregnant;
- disaggregation of both pathogens and people: when categories are divided into smaller and smaller groups it poses a problem for risk assessment generally;
- there may be other factors involved, for example, the amount of time the food has been stored which are not apparent from the data;
- in the case of L. monocytogenes contamination the amount of data is always small and as it is not a foodborne zoonosis it cannot be traced back to an animal source. The term “source attribution” really refers to an animal reservoir so is not really relevant in the context of a pathogen widely distributed in the environment.
8.6 Members noted that pre-prepared sandwiches featured near the top of ranking in Table 2. It was pointed out that most of the known outbreaks were associated with sandwiches procured for use in hospitals rather than those sold in the retail sector. A member commented that risk assessment should include weighing the risk of harm against the benefits, so although there may be a potential risk, say of using sandwiches for elderly patients in hospital, this may be outweighed by benefits such as ease of preparation, relatively low cost, high calorie intake etc.
8.7 It was suggested that food that came near the top of Table 2 could be used to indicate those food groups where there was a need for further research, either by surveillance, or studying people’s behaviours.
8.8 Although Members felt the approaches gave useful information, a key consideration was how that information might be used by people who were not aware of the limitations identified. They considered the results could be used for targeted advice to specific groups of people in specific circumstances rather than general advice for the whole population. This might include advice to vulnerable groups on being careful with certain foods, for example, by observing use-by dates. Joy Dobbs commented that risk ranking helped to clarify broad patterns that are reasonably reliable, which might help to highlight any new areas where current consumer advice was lacking.
8.9 Members suggested that using sensitivity analyses and multiple dose response relationships would improve the risk ranking approaches. A semi-quantitative risk assessment tool (Risk Ranger) which uses point estimates might be worth considering. Members were also aware that other organisations were engaged in similar work: EFSA are producing a risk ranking toolbox and WHO are doing some work using expert elicitation. John Bassett mentioned a paper he was producing for FAO on risk ranking approaches which the committee could consider when it becomes available.
9. Street Spice Outbreak
9.1 Dr Kirsty Foster (Consultant in Health Protection, Public Health England) and Dr Russell Gorton (Consultant Epidemiologist, Public Health England) were invited to give a presentation on the findings from the outbreak of Salmonella Agona PT40 and other GI pathogens associated with raw curry leaves in North East England in early 2013. Dr Claire Jenkins (from PHE Gastrointestinal Bacteria Reference Unit) also contributed to the presentation. Dr Foster reported that the outbreak occurred at a popular charity event held in Newcastle upon Tyne between 28 February and 2 March 2013 attended by approximately 12,000 people. Newcastle City Council Environmental Health Team (EHT) and the event organisers started to receive reports of illness from event attendees from 4 March 2013 (about 15 to 20 people) with numbers increasing sharply over the following days (around 400 people reported between 7 to 10 days). She explained that the need for case finding was reduced as there was a lot of discussion on social media sites (Twitter and Facebook) linked to the event, people going to their Family Doctor and reports made to the Council’s EHT. The outbreak investigation was coordinated through a multi-agency outbreak control team (OCT).
9.2 Members were informed that further cases were identified through an on-line cohort study (messages distributed via Twitter and Facebook). Investigations revealed there was common exposure to a particular stall and specific food items from the stall catered by a guest chef. Key foods were dosas, uttaphums and vadas (pancake style foods with vegetarian fillings). Coconut chutney was served as accompaniment with the above dishes. Stool samples were collected from those who reported illness who were symptomatic and these were tested for standard bacterial pathogens (Salmonella, Campylobacter, E.coli O157, and Shigella), Cryptosporidium, Norovirus, Clostridium perfringens and Bacillus cereus. Later on in the investigations multiplex PCR was employed specifically for the bacterial pathogens.
9.3 Dr Foster described the case definition as a person with diarrhoea who became ill between 12 hours and 5 days after attending the food festival. Total number of cases reported was 592 with those affected being mostly young healthy adults mainly aged 20-49 years (52.5% females). From the routine culture carried out it was reported that of 104 stool samples submitted there were 29 cases of confirmed Salmonella (25 were a new strain of Salmonella Agona Phage Type 40 not been seen in the UK before either in food or humans; other Salmonella serovars were S. Cerro, S. Hadar, S. Typhimurium and an untyped Salmonella). Salmonella Agona PT 40 was isolated from a batch of curry leaves used at the event. As there was concern on the low positivity rate for Salmonella amongst cases, the OCT arranged for multiplex PCR for bacterial pathogens to be undertaken at the Public Health Laboratory for London. A nested case control study was used to confirm the clinical significance of the PCR and culture results.
9.4 Concerning the conclusions Dr Foster highlighted that:
- Contaminated curry leaves in an uncooked coconut chutney were the source of illness among people who consumed the product at the street spice festival. Further work was recommended in order to understand levels of contamination and effective control methods.
- Food operators did not understand the risks associated with the use of raw curry leaves, and were uncertain about guidance for their use. It was recommended that knowledge and training of food operators should be addressed.
Lessons learnt included:
- the need to use consistent methods for microbiological investigations of human and food /environmental specimens.
- that mixed pathogen outbreaks may be more common than previously recognised, meaning that detection of a single pathogen should not necessarily halt wider microbiological investigation using new technologies to identify mixed infections.
9.5 The Chair invited comments and questions on the presentation. The following points were made in discussions:
- Prof Rick Holliman declared an interest concerning the enteric pathogens multiplex PCR which he said was developed by his colleagues at the London Public Health Laboratory and deployed under his direction. He pointed out that the assay, had been developed for the 2012 Olympics, and was accredited for outbreak investigations of affected populations but not yet fully validated for the diagnosis of individual patients. He explained that multiplex PCR results must be interpreted with caution, and subjected to appropriate statistical analysis. It was acknowledged that multiplex PCR could be a powerful tool in future investigations.
- The issue of communication between people affected by the outbreak and the OCT during the investigation period was raised. It was confirmed that letters were sent to everyone the OCT was aware of being affected by the outbreak. The OCT ensured that everyone concerned was kept updated via letters and through social media. It was added that the food festival organisers’ twitter account was immensely helpful in disseminating information during the investigation.
- The finding in relation to Shigella was queried. It was explained that the PCR used for Shigella is very sensitive and the organism is difficult to culture in comparison with other organisms such as Salmonella. It was noted that laboratories often focus their testing activities on the most likely target organisms. As Shigella has become rarer since the 1990s it now receives less investigative efforts than Salmonella and VTEC.
- Discussion included the effectiveness of the detection method, and raised the possibility of wider use of multiplex PCR. It was suggested that future investigations could consider the methodology used for testing/analysing animal samples. Dr Foster commented that although adequate samples were not available from all the people who were ill, the consensus view was that a proportion of the ill people had a mixed pathogen infection associated with consumption of a product contaminated with mixed animal and human faecal waste.
- The Committee queried recommendations for further research on the prevalence of contamination on curry leaves, and the growth/control of pathogens in uncooked food dishes. It was suggested some of these risks are already well recognised, and that further primary research may be unnecessary. It was, however, agreed that relevant information should be collated to inform risk assessment.
- A Member suggested there were gaps in the microbiological findings, such that other contaminated foods served at the festival may have contributed to the outbreak. It was explained that the OCT’s hypothesis (that contaminated curry leaves that were used uncooked in a chutney were the source of illness in people who attended the festival) was supported by the epidemiological and microbiological findings from both human and food samples.
- There was a comment concerning the twitter streams and effectiveness of twitter during the investigation and a question as to whether this medium could be used again in the future. Dr Foster confirmed that the twitter streams were filtered and that twitter provides an additional means of communicating with the public on food safety issues.
- A Member sought clarification on the conclusion that indicated that the use of contaminated raw curry leaves used uncooked in the preparation of coconut chutney by a guest chef was the source of illness in the people who consumed the chutney. It was confirmed that microbiological tests were carried out on other leaves sold locally (in Newcastle) and the results were negative.
- A Member commended the caterers in the North East in the way they cooperated with the OCT during their investigation.
- It was observed that although the FSA provides advice on relevant control measures (how to use raw leaves including curry leaves); it was not unknown for fresh herbs and spices to be contaminated with Salmonella. It was suggested that the Committee may wish to consider if the current guidance is adequate.
- A Member commended the creativity of the OCT in dealing with a difficult and complex investigation, and highlighted that the lessons learned from the investigation should be useful for dealing with future outbreaks. He noted that novel means of communication such as social media may be useful in contacting diffuse groups involved in festivals and similar types of events.
9.6 The Chair echoed the members’ thanks for the excellent presentation acknowledging that it provided food for thought in relation to the forthcoming horizon scanning exercise.
10. Epidemiology of Foodborne Infections Group
10.1 The Chair invited Dr Cook to update Members on the outcome of the EFIG meeting which took place on 9 December 2013. He reported there was a reduction in reports of Salmonella in cattle, sheep, ducks and other bird species not subject to Salmonella National Control Plans (NCPs) in 2013 compared to 2012. The number of reports from pigs was roughly comparable to the same period in 2012. Between January and September 2013, there were a total of 859 reports of Salmonella from livestock species not subject to Salmonella NCPs. This is almost identical to January to September 2012 (857 reports), and a 7% decrease compared to the equivalent period in 2011 (921 reports).
10.2 Trends in laboratory reports for Salmonella, Campylobacter, Listeria monocytogenes and E. coli O157 in humans were reported. The number of cases of Salmonella infection has continued to decline in frequency in 2013, with 6,412 isolates reported in the UK, a 7% reduction on the same period in 2013 and equivalent to 47% of isolates reported in 2003.
10.3 Campylobacter continues to decline in England, Scotland and Wales, but is increasing in Northern Ireland. There was still a significant difference in the reporting rates for Northern Ireland against England, Scotland and Wales, with the rate approximately 39% less in Northern Ireland. Prior to 2009, the reported rate of campylobacteriosis in Northern Ireland was consistently around 50% of that in the other countries. There is ongoing work to try and pinpoint the reason for the different rate in Northern Ireland.
10.4 There were 33 foodborne general outbreaks reported in the first 9 months of 2013 in England and Wales. The largest outbreak reported was the Salmonella Agona PT 40 and other GI pathogens associated with curry leaves used at food festival in North east England in February-March. Other outbreaks of interest included Salmonella Goldcoast associated with whelks, Salmonella Typhimurium DT120 associated with a hog roast and E. coli O157 PT2 linked to watercress.
10.5 Members were informed that EFIG has begun looking at how the animal and human data can be better aligned to facilitate comparison of patterns and in recognition of the various caveats associated with the different datasets. At present this has only been undertaken for Salmonella as the data is more comprehensive than for other pathogens.
10.6 Dr Cook also outlined the updates EFIG received including the work of the ACMSF working group on antimicrobial resistance and a presentation on selected highlights from CHRO the 17th International workshop on Campylobacter, Helicobacter and related organisms which was held in Aberdeen 15-19 September 2013.
10.7 It was noted that patterns of human foodborne infections were unusual in 2013, which may have been related to the unusual weather patterns for that period.
11. Committee subgroups
11.1. Prof David McDowell updated the Committee on the second meeting of the Antimicrobial Resistance (AMR) Working Group. The group’s discussions were summarised in paper ACM/1139.
11.2. Prof McDowell reported that the group had considered the recent finding of LA-MRSA in turkeys on a farm in East Anglia. Members were informed that in October 2013, 4 turkeys were submitted to an Animal Health and Veterinary Laboratories Agency lab for diagnosis and Staphylococci were cultured from the lung of one of these birds which proved to be LA-MRSA ST398 spa-type t011. The strain was found to be resistant to tetracyclines, penicillins and methicillin but susceptible to a number of other antimicrobials, including macrolides and fluoroquinolones. The strain isolated was common in livestock in continental Europe but had not previously been detected in livestock in the UK. This strain had been isolated in the UK from a few human cases and also detected in horses and in about 5 of 1500 bulk milk samples from dairy herds. The group concluded there was little evidence in relation to LA-MRSA in the UK, but the available evidence did not suggest a foodborne issue in the UK or Europe at present. They agreed to monitor the situation as it develops, both in the UK and in other parts of Europe.
11.3. Members were informed that the group reviewed a recent published research paper which suggested that DNA fragments from food consumed by humans can carry complete genes, without degradation into the human circulatory system. They agreed that although the research raised some interesting questions and suggested transfer of genes into the circulatory system was theoretically possible, it was unlikely to pose a significant risk in relation to the public health risks from antimicrobial resistant organisms. However, it was agreed the group should keep a watching brief on any further research in this area.
11.4. The group also considered EFSA’s scientific opinion on the public risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals. They endorsed these scientific opinion’s conclusions and recommendations. It was noted that there was an ongoing push for harmonisation concerning human and animal ESBL surveillance in Europe. Although the scientific opinion was published in 2011, the group agreed that it had highlighted the importance of ESBLs and/or AmpC-producing bacteria in food and food producing animals. The group agreed that there is a lack of evidence of the prevalence of ESBL and/or AmpC-producing bacteria in the food chain.
12. Dates of future meetings
12.1 Members were asked to note the dates of the ACMSF meetings for 2014 (26 June and 2 October) and 2015 (29 January, 25 June and 1 October).
13. Any other business
13.1 The Chair invited Mr Javier Dominguez to update the Committee on the ongoing changes in the FSA. Mr Dominguez informed members that the food safety and Chief Scientist groups have merged into a new group headed by Steve Wearne (FSA Director of Policy). The aim of the merger is for close integration of science and policy making. The management structure for the new group is as follows:
- Director of Science, Evidence and Research (yet to be appointed)
- Head of Policy Programmes (headed by Michael Wight)
- Head of Directorate Support (yet to be appointed)
13.2 Mr Dominguez explained that ACMSF and other Scientific Advisory Committees would be the responsibility of the Director of Science, Evidence and Research, along with Science infrastructure, analytical sciences resources, policy support and risk assessment. ACMSF will retain its secretariat to provide administrative and scientific support for the work of the Committee.
13.3 The Chair informed members that Messrs Paul McMullin and John Bassett were attending their last ACMSF meeting as members as they retire from the Committee when their current period of appointment ends on 31 March 2014. They have given the maximum length of 10 years service to the ACMSF. The Committee thanked them for all their hard work and the commitment and support they have provided to the Committee for the years they served as members.