ACMSF Meeting minutes 5 December 2001

Minutes of the 42nd meeting of the Advisory Committee on the Microbiological Safety of Food held on 5 December 2001 at Trinity House, Trinity Square, Tower Hill, London EC3, starting at 10 am.

Present

Chair
Professor D L Georgala

Members
Dr G R Andrews
Dr D W G Brown
Professor M J Gasson
Dr K M Hadley
Professor T J Humphrey
Professor P R Hunter
Mrs P Jefford
Professor A M Johnston
Mr A Kyriakides
Ms E Lewis
Professor P Mensah
Dr S J O’Brien
Dr Q D Sandifer
Dr T D Wyatt

Assessors
Mr P J R Gayford (DEFRA)
Professor C H McMurray (NIDARD)
Dr R Skinner (FSA)

Secretariat
Dr J Hilton (Medical Secretary)
Mr C R Mylchreest (Admin Secretary)
Mrs E Stretton (Secretariat)
Miss M Castle (Secretariat)
Mr D Gray (Secretariat)
Mr S Rahman (Secretariat)

Others
Dr R T Mitchell (PHLS) for items 6 and 7
Dr G K Adak (PHLS) for item 7
Dr J P Back (FSA) – for item 8
Dr K Callaghan (FSA) – for item 9

Members of the public
Dr Roy Betts (Campden and Chorleywood Food Research Association)
Miss Claire Boville (Food Standards Agency)
Rosemary Brook (National Dairy Council)
Bridgette Clarke (Geest plc)
Mr David Clarke (Assured Food Standards)
Dr Hilary Close (National Council of Women)
Kaarin Goodburn (Chilled Food Association)
Mr Simon Kane (Kraft Foods UK Ltd)
Mr Alan Kennedy (Paratuberculosis Awareness & Research Association)
Dr Ed Komorowski (Dairy Industry Federation)
Ms Sheila Lakes (Zhitz International)
Mr Richard Lawley (Leatherhead Food Research Association)
Dr Christine Little (Public Health Laboratory Service)
Mr Alan Long (Vegetarian Economy & Green Agriculture)
Mr Alan Lyne (ADAS)
Ms Niki Lyons (Food Standards Agency)
Isobel MacKinnon
Ms Helen McDermott (Food and Drink Federation)
Mr Joe Pitchford (DEFRA)
Miss Satnam Sagoo (Public Health Laboratory Service)
Jane Seymour (Food Standards Agency)
Mr Michael Scott
Dr Norman Simmons (Emeritus Consultant in Microbiology to the Guy’s and St Thomas’ Hospital Trust)
Mr Chris Pratt (Food Standards Agency)
Mr Alan Proctor (Zhitz International)
Dr Thomas Quigley (Food Safety Promotion Board of Ireland)
Teresa Pibernat Reixach
Mr Martyn Rogers (Reading Scientific Services Ltd)
Ms Claire Wilkes (Food Standards Agency)
Mr Mick Wood (Norpath Laboratories)
Miss Orla Yeates (Food Standards Agency)

1. Chair's introduction

1.1 The Chair welcomed Members to the Committee's forty-second meeting, its second to be held in public. He extended a warm welcomed to members of the public present. He also welcomed Professor Paul Hunter who had been appointed to the Committee in 2001 and was attending his first meeting.

1.2 Professor Georgala explained that a 30 minute slot had been allocated at the end of the agenda for public questions. He said that questions or statements need not be confined to agenda items but could cover the Committee's work more broadly. The proceedings were being recorded to assist the production of minutes and individuals were asked to state their name and affiliation, where appropriate, for the record. An information paper (ACM/551) had been prepared providing some background about the ACMSF and members. An updated list of members of the public attending had been tabled as ACM/554 (Rev 1).

2. Declarations of interest

2.1 The Chair reminded Members of the need to declare any financial or similar interests in respect of items included on the agenda. In relation to agenda item 8, Professor Hunter reported that he had been principal investigator on a research project funded by the Drinking Water Inspectorate looking at Mycobacterium avium subsp. paratuberculosis in UK drinking water supplies.

2.2 Professor Georgala also reminded Members of the need to inform the Secretariat of their more general interests as soon as possible, so that they could be recorded in the Register of Members' Interests which would be included in the Committee's Annual Report for calendar year 2001.

3. Apologies for absence

3.1 Apologies for absence were received from 4 Members – Miss Davies, Mr Peirce, Mr Piccaver and Professor Smith. Apologies were also received from 2 of the Departmental Assessors – Dr Doherty (NIDHSSPS) and Dr Pryde (FSA/S).

4. Minutes of the 41st meeting (ACM/MIN/41)

4.1 Members approved the draft minutes as a correct record of the forty-first meeting.

5. Matters arising (ACM/546)

5.1 The Secretariat had prepared a record (ACM/546) of matters arising from the forty-first meeting of the Committee. This was noted.

5.2 In relation to a question about the proposed Campylobacter workshop (paragraph 7.4 of ACM/MIN/41), the Secretariat reported that moves were in hand to finalise the membership of the Campylobacter Working Group and that it now looked likely that the workshop would be held in February 2002.

5.3 One Member asked, in relation to paragraph 9.4 of ACM/MIN/41, whether the Food Standards Agency (FSA) had any plans to produce a booklet, or something similar, to assist small and medium size enterprises in better understanding HACCP. The Secretariat said that there were no immediate plans to do so but that they would investigate matters further and report back to the Committee at a later date.

6. The microbiological safety and status of ready-to-eat fruit and vegetables (ACM/476 and 510)

6.1 The Chair reminded Members of the ACMSF's long-standing interest in building up its understanding and knowledge in this area where information was often difficult to come by. The Public Health Laboratory Service (PHLS) had produced a briefing paper (ACM/476) for the Committee in 2000. At that time, ready-to-eat fruit and vegetables gave the Committee no cause for serious concern on food safety grounds, but Members were nevertheless keen to keep in touch with developments both nationally and internationally. PHLS had kindly agreed to provide regular updates. Professor Georgala welcomed Dr Bob Mitchell and Dr Bob Adak from the PHLS who had produced an update paper (ACM/510).

6.2 Dr Adak introduced Section 1 of the paper, which gave an update on foodborne general outbreaks associated with salad, fruit and vegetables in England and Wales in 2000. Six of 95 (6%) foodborne general outbreaks of infectious intestinal disease reported to the PHLS Communicable Disease Surveillance Centre (CDSC) had been associated with the consumption of salad, fruit and vegetables. Four followed a “normal” pattern (ie. involved cross-contamination or contamination by infected food handlers) but there had been 2 large outbreaks occurring in the summer of 2000 and linked to the consumption of lettuce.

6.3 Dr Adak reported that in August 2000, an outbreak had occurred among 174 people, mostly young adults living in the West Midlands NHS Region and adjoining parts of the North West NHS Region. The infection had been caused by Salmonella typhimurium DT104 resistant to 6 antimicrobials. Illness had been severe. Around 40% of cases had required hospital admission. There had been 1 fatality. Investigation of local clusters supported the hypothesis that the likely source of infection was lettuce prepared in small and medium sized fast food outlets. Fast food outlets associated with clusters of cases were found to have common suppliers of salad vegetables but the complexity of distribution chains had prevented tracking the salad vegetables back to the original supplier. In addition, given the short shelf-life of salad vegetables, it had not proved possible to obtain any suspect foods for microbiological analysis.

6.4 Dr Adak reported that there had been another outbreak in September 2000 affecting 124 mostly young adults living in the Northern and Yorkshire NHS Region. The infection had been caused by a strain of S. typhimurium DT204b resistant to 12 antimicrobials. PHLS had been able to learn, through Enter-net collaboration, of a simultaneous outbreak affecting 183 people in Iceland. Cases of infection caused by the same strain of S. typhimurium had also come to light in Scotland, the Netherlands and Germany. In Iceland, a link had been established with the consumption of imported lettuce but, again, it had proved impossible to trace the source of supply.

6.5 Dr Adak concluded that, whilst salad, fruit and vegetables featured in a relatively small proportion of foodborne general outbreaks (

6.6 Professor Hunter explained that he had been involved in the investigation of the DT104 outbreak. A remarkable feature had been that infection had been largely confined to lettuce sold through fast food outlets. Dr Hunter suggested that there was nothing inherently special about fast food outlets in terms of the origin of the lettuces used. It seemed inconceivable that some lettuces from the same source as those associated with the outbreak would not also have gone into people's homes; but there had been no evidence of their having caused illness. Dr Hunter suggested that a possible explanation might be that lettuces were washed more effectively in the domestic setting than in fast food outlets because, if lettuces were to be kept for some time, over-washing in a fast food outlet would make them go limp. There might be advantage in undertaking work to identify an adequate washing system for use in fast food outlets which cleansed lettuces without making them go limp.

6.7 In further discussion, Dr Adak confirmed that washing practices in fast food outlets did not form part of the CDSC's epidemiological investigation (which involved obtaining information from those who were ill and asymptomatic controls), but that environmental health officers were likely to have investigated these aspects. This information was regarded as essential in any search for improved washing practices. Members stressed the importance of being able to trace produce involved in outbreaks of foodborne intestinal disease back down the supply chain to the point of production. However, they also acknowledged that supply chains were highly complex and traceability raised questions of practicality and expense, not least because imported produce now made up a significant proportion of salad, fruit and vegetables on the UK market.

6.8 Turning to Section 2 of the paper, which provided an update on the microbiological status of ready-to-eat fruit and vegetables, Dr Mitchell said that there were remarkably few surveillance studies of such produce. The PHLS/LACOTS studies were among these. While PHLS/LACOTS studies were not structured to be representative of the UK market as a whole, they nevertheless provided a useful and rapid snap shot.

6.9 Dr Mitchell then reported on 3 PHLS/LACOTS studies, 1 of which had been carried out in May-June 2000, 1 in May-June 2001, and 1 in September-October 2001. The first had involved a study of ready-to-eat organic fruit and vegetables on sale in the UK. 3,200 samples had been collected, 3,185 (99.5%) of which had been found to be of satisfactory/acceptable microbiological quality. There had been a complete absence of pathogens (Listeria monocytogenes, Salmonella, Campylobacter and Escherichia coli O157) and a low incidence of E. coli and Listeria spp. Overall, agricultural, hygiene, harvesting and production practices had been good.

6.10 The second study had been of retail, prepared, pre-packed ready-to-eat salad vegetables. Results and supplementary information were still being analysed. 3,851 samples had been collected. No E. coli O157 or Campylobacter spp. had been detected. Listeria monocytogenes had been detected in 1 sample at

6.11 The third study was of open, prepared, ready-to-eat salad vegetables from catering and retail premises. Data from the survey were still being collected and collated. Around 4,000 samples had been analysed to date. No pathogens had been detected.

6.12 In discussion of the 3 surveys, Members noted that chlorinated water was normally used by the larger enterprises in washing these types of produce. This tended to remove gross soil and other contamination but was not certain to remove all bacterial contamination. There was also evidence that bacteria could be taken up by some plants and become internalised. It was therefore important to ensure that hygienic growing techniques were employed, in order, as far as possible, to reduce contamination at source. However, given the fact that production was not under sterile conditions, while great effort was made to improve cultivation practices, it was not possible to guarantee pathogen-free produce. The use of chlorine in wash water (and the use of alternatives like ozonated water) could help but did not provide a complete answer. Moreover, it was reported that the use of eg. chlorinated water was not authorised by the Soil Association for the production of organic fruit and vegetables.

6.13 Members concluded that 2000 outbreak data and the surveillance results provided by PHLS offered reassurance that ready-to-eat salad, fruit and vegetables did not normally constitute a serious public health risk. Such produce made up a small proportion of the vehicles associated with foodborne general outbreaks of infectious intestinal disease. However, in year 2000 it had been associated with 2 large-scale food poisoning outbreaks and there was a need to avoid complacency. Members felt that it would be helpful if the Food Standards Agency would keep the ACMSF informed of developments in international fora such as Codex Alimentarius. The ACMSF would also find it useful if the FSA could provide a view on the structure of the supply chain and whether the data provided by PHLS could be usefully used to exert pressure for improvements on the various players in that chain. In making these requests, Members recognised that this was a fast moving area involving short shelf-life products which needed to be moved quickly from field to catering outlets/shops.

6.14 Members also noted that many in the catering industry would not regard salads as a major vector for food poisoning organisms and that that could be a cause for some complacency. It would be helpful if, in the context of its planned food hygiene publicity campaign, the FSA could remind caterers that it was not only meat but vegetable matter too that needed to be properly handled if it were not to become a vector for food poisoning. Reminding suppliers of the importance of traceability would also help improve the food chain. Members also noted the proliferation of guidelines and codes of practice – eg. on sewage sludge treatment and application, agricultural waste, prepared salads etc. – and proposed that the FSA might review these from a microbiological perspective to see what impact they were having and whether they might have a greater impact in relation to microbiological control. Finally, Members suggested that there would be benefit in drawing the attention of consumers and investigators to the potential risk from salad, fruit and vegetables.

6.15 The Chair thanked Dr Mitchell and Dr Adak for their contribution to the debate and requested further regular progress reports, the next in perhaps 1 year's time.

7. Ready-to-eat foods with added spices (ACM/509)

7.1 Dr Mitchell (PHLS) introduced the results of a PHLS/LACOTS survey, carried out in September-October 1999, of ready-to-eat foods to which spices had been added. The study stemmed from concern by LACOTS, Port Health Officers (PHOs) and Environmental Health Officers (EHOs) that imported spices were occasionally contaminated with Salmonella, which raised questions of whether importation could be refused. Importers tended to argue that spices would be going for further processing or would be fully cooked before use, and that they should therefore be treated no differently from, say, raw poultry which could be imported despite being contaminated with Salmonella. However, in view of changes in the UK diet and the increased use of spices as garnishes or as constituents of cold dishes, it had been decided to survey ready-to-eat foods to which spices had been added.

7.2 A total of 1,946 ready-to-eat foods from sandwich bars, caf¿s, public houses, restaurants, specialist (non-retail) sandwich makers, bakers, delicatessens, market stalls and mobile vendors had been examined. In each case, spices had been added after cooking. 1,291 (66%) foods sampled were found to be of satisfactory microbiological quality, 599 (31%) were unsatisfactory and 56 (3%) were of unacceptable quality. No Salmonella was found. Unsatisfactory results were mostly due to high Aerobic Colony Counts, Enterobacteriaceae and Bacillus spp. Unacceptable results were due to high levels of B. cereus, other Bacillus spp. and E. coli.

7.3 Examination of spices or spice ingredients revealed that B. cereus was present in 142 (19%) samples, other Bacillus spp. in 399 (53%) samples, and S. enteritidis PT11 in 1 sample.

7.4 The conclusion drawn from the survey was that ready-to-eat foods with spices added post-cooking were not posing a problem to the public in terms of Salmonella contamination. Fairly high levels of Bacillus spp. were found, reflecting the potential for contamination during the drying process (in the open air in the country of origin). Drying down also had the effect of concentrating the spore count per unit of material. As a result of the study, PHLS and LACOTS produced advice for EHOs, which drew attention to the need to include spices as part of microbiological hazard analysis, in relation to both Salmonella and Bacillus spp. Also, the fact that high levels of Bacillus spp. had been found in products stored for long periods re-emphasised the need for strict hygiene practices and appropriate time and temperature control. EHOs were reminded of this fact and the need for it to be drawn to the attention of industry. Finally, the survey helped inform LACOTS advice to PHOs on inspection of spices at port of importation and the action to be taken if Salmonella was found.

7.5 In discussion, it was clear that Members found the results of the survey re-assuring, although they noted that people generally might not be aware of the potential microbiological risks associated with the use of uncooked spices. They noted that Bacillus cereus did not feature prominently as a cause of food poisoning outbreaks and, when seen, was often associated with rice. Bacillus cereus infection had a short incubation period and was associated with 2 toxins giving 2 different clinical presentations. Illness was short-lived, but unpleasant. A key factor was that the organism had to grow to produce sufficiently high levels of toxin. Long-term storage thus potentially increased the risk and this needed to be drawn to the attention of consumers, alongside the need for proper handling, including appropriate temperature control. Members felt that this might feature, to advantage, in the advice which the FSA was promulgating as part of its foodborne disease strategy. The Chair thanked Dr Mitchell for his presentation.

8. Mycobacterium avium subsp. paratuberculosis (ACM/547)

8.1 By way of background, the Chair explained that for many years the ACMSF had had an interest in Mycobacterium avium subsp. paratuberculosis (MAP). This interest originated in information about work carried out at Queen's University, Belfast indicating that MAP might be more heat resistant than had previously been thought and that that heat resistance might imply that it could survive the commercial pasteurisation of milk. Results were based on laboratory work. The organism was very difficult to work with. As a result of this early work, the ACMSF had called for a survey of retail milk. This was carried out by the FSA over an 18 month period and the results were presented to the ACMSF in September 2000. Having carefully considered the results, the ACMSF satisfied itself that MAP could survive pasteurisation and was present in a very small percentage of retail milk. There had been on-going debate about the possible role of MAP as a cause of Crohn's disease, a chronic and distressing illness in humans. The evidence considered by the ACMSF at that time about the link between MAP and Crohn's disease had been inconclusive. As it seemed unlikely that this question would be resolved in the short-term, the ACMSF had requested the FSA to bring together all parties concerned with milk production to see whether this organism could be removed from, or reduced in, milk. In response, the FSA held a major workshop of stakeholders in May 2001 and had now produced a draft strategy for controlling MAP in cows' milk.

8.2 Dr Back (FSA) introduced the draft strategy (ACM/547) and invited Members' comments. He drew attention to ACM/553 which reviewed evidence relating to the claimed link between exposure to MAP and Crohn's disease in humans. Consideration of this aspect would continue but, in the meantime, the FSA was resolved to adopt a precautionary approach to reduce human exposure to MAP. Dr Back said that the draft strategy would be the subject of public consultation and there would also be an open meeting, on 23 January 2002 to discuss the draft and help the FSA to finalise the strategy. The strategy recorded what actions had been taken to date and also highlighted what the Agency thought still needed to be done, both in the shorter and longer-terms. There had been a good deal of input from the Department for Environment, Food and Rural Affairs (DEFRA) who also had a key role in implementing the strategy. The long-term aim was to get MAP out of animals, although the difficulty of this task was recognised. There were still gaps in the science and information bases, and in knowledge of the extent of Johne's disease (the bowel disease in animals caused by MAP) in the national herd. The need was for a baseline against which progress in reducing MAP could be measured. However, better detection methods were required to enable an effective survey of the prevalence of Johne's disease in the national herd to be carried out. The position was further complicated by evidence of a wild life reservoir of MAP (in eg. stoats, badgers, rabbits) and the effect this might have on the carriage of the organism. This was potentially very important in terms of the possible risk of cattle being re-infected through environmental exposure pathways.

8.3 Notwithstanding these difficulties, Dr Back felt that there were things which could be done immediately. There was good information on transmission and the natural history of MAP in cattle. A key stage was when cattle were young. There appeared to be a 2 year period before MAP manifested itself. Avoiding infection during this early period might offer protection from disease in later life. Good biosecurity was very important in terms of reducing the exposure of cattle to MAP. Some options carried implications for animal welfare (eg. stopping using bulked colostrum) and these needed to be recognised. The strategy sought to identify the various measures which might be taken now as a means of controlling Johne's disease on-farm. These would clearly not provide a complete answer and other options also needed to be explored. One of these was vaccination and research was needed on the efficacy of currently available vaccine.

8.4 As regards implementation of the proposed strategy, Dr Back reported that DEFRA planned a survey of MAP infection (depending on the assessment of the efficacy of currently-available tests) and would also be producing 2 advisory leaflets, both of which should be available in 2002. DEFRA's post-Foot and Mouth Disease advice to farmers on avoiding importing animal diseases during re-stocking included some information on MAP, although there were few Johne's-negative herds (and thus MAP-free animals) in the UK. There were some measures which could usefully be adopted at the milking stage to reduce the chances of infection by reducing levels of faecal contamination. There had already been a significant amount of work by industry to reduce faecal contamination. Research was needed into the most effective methods of teat cleaning, which had knock on benefits for the reduction of mastitis. Current advice on hygiene practices during milking needed to be reviewed with a view to issuing consolidated guidance and disseminating it to identified target audiences. The FSA was taking a number of steps in the context of its overall foodborne disease strategy to improve the general quality of milk. One aspect of this was a review of the work of the Dairy Hygiene Inspectorate (DHI) to see whether the DHI's advisory role could be formalised. The latest edition of the FSA's research requirements document would call for research proposals on teat cleaning.

8.5 Dr Back said that another important area for attention was post-milking control. Ineffective pasteurisation gave cause for concerns not only in relation to MAP but as regards many other organisms too. The industry had undertaken a lot of work to ensure that milk was pasteurised correctly. There was some concern about the smaller enterprises and on-farm pasteurisers which would be addressed through a combination of guidance and inspection. Another important consideration was whether increasing pasteurisation times was an effective counter-measure. There was some laboratory evidence to support this hypothesis and the majority of the larger dairies, when the issue first came to the fore in 1998, increased pasteurisation times from 15 to 25 seconds. Increasing the holding time seemed to be more effective than increasing the temperature. Although increased holding times did not provide a complete answer, as the results of the FSA survey demonstrated, Dr Back said that the Agency felt that MAP was less likely to survive when exposed to pasteurisation temperatures for this extended period of time. This did not obviate the need for further research on the most effective time/temperature combinations.

8.6 As regards action in the short-term, Dr Back reported that the dairy industry intended to publish a code of practice on HTST (high temperature short time) pasteurisation shortly. The FSA welcomed this initiative and would be considering, once the code was finalised, means of making it widely available. The work of the DHI was being reviewed in the context of enforcing pasteurisation. There was also a LINK research project, part funded by DEFRA and part funded by the dairy industry, and being carried out at the Hannah Research Institute, looking at the conditions required to eliminate MAP. Care was being taken to ensure that the work mimicked commercial pasteurisation equipment.

8.7 In conclusion, Dr Back confirmed that the draft strategy would evolve in the light of comments received from the ACMSF and as a result of the consultation process and the open meeting. He was aware that the Inter-Departmental Surveillance Group on Diseases and Infection in Animals was proposing to develop a strategy for MAP surveillance in animals and this would be built into the strategy.

8.8 In response to questions from Members, Dr Back said that he was unaware of any data linking milk consumption patterns with the prevalence of Crohn's disease. Milk consumption was a clear exposure pathway for MAP but there were potentially other vectors including water and meat. One Member commented that heat sensitivity was a key issue in relation to MAP which was not reflected sufficiently strongly in the draft strategy. The organism was extremely difficult to deal with, being slow growing and also growing in large clumps. Being hydrophobic, it could also sit on the surface of liquids. Work even in the laboratory on, eg, breaking up clumps needed to be done with an exceptional degree of rigour. More research was needed to assist the understanding of the heat response of this organism before an authoritative view could be given on the efficacy of a 25 second holding time.

8.9 Another Member questioned, given the additional cost associated with longer holding times and the legislative requirement to pasteurise for only 15 seconds, how it was proposed to persuade those not already doing so to increase their holding times to 25 seconds. How too would imported milk be tackled ? And were there any implications for cheese? Dr Back said that once a strategy had been agreed, detailed consideration could be given to the impact and practicability of what was proposed. Most imported milk was UHT which was unlikely to contain viable MAP. The strategy could therefore concentrate on UK pasteurisers. It seemed unlikely that the FSA would want to pursue a legislative approach to longer holding times but 25 seconds might be achievable through persuasion. It should be borne in mind that the strategy was not seeking to provide rapid solutions but improvements over time. Action in respect of cheese was problematical because longer holding times would affect the cheese making process and could also affect the organoleptic qualities of the cheese.

8.10 Other questions included whether vaccination controlled the carriage of MAP or just prevented the progression to Johne's disease in animals carrying the organism; and, in terms of wild life reservoirs, whether all strains of MAP were genetically similar or whether only specific strains affected livestock as opposed to, eg, rabbits. The question was also posed as to whether there had been any investigation of suggestions that when small pasteurisers had incorporated on-line cream separators, thus speeding up flow through the pasteurisation plant, holding times were actually being reduced below the 15 second statutory minimum.

8.11 On this last inspection point, Dr Back acknowledged the importance of proper enforcement, including phosphatase testing and microbiological examination. He thought the Dairy Industry Federation's HTST code would help. Although that was aimed at the larger enterprises, it could be adapted for use by the smaller operators too. In addition, a lot of processing information had been collected as part of the FSA's milk survey and this provided a useful basis on which to assess the effectiveness of pasteurisation operations. However, the FSA was conscious of the need to ensure that the smaller-scale operators received appropriate information to ensure that they were carrying out pasteurisation effectively and to make them aware of the MAP/Crohn's issue. Overall, it appeared that pasteurisation was being carried out effectively. In response to the vaccination question, Professor Johnston reported that, while the Johne's vaccine had limited use because of cross-reactivity with tuberculin testing, for herds with a significant Johne's disease problem, it was effective in damping down clinical cases and reducing the output of MAP.

8.12 Among other points made in discussion, were that :-

  • there were no reliable data on the prevalence of MAP in the UK herd. A proper survey was dependent upon the development of better diagnostic tests;
  • there had been a tremendous drive for clean milk production at the top end of the market (driven by total bacterial counts, somatic cell counts, herd schemes, mastitis control schemes) but the smaller operators continued to give cause for concern, and enforcement had a key part to play in rectifying the situation;
  • sheep and goats milk, including imported organic product, was a potential source of consumer exposure to MAP;
  • development of an effective vaccine was a key requirement if Johne's disease was to be effectively tackled;
  • a call for universal adoption of a 25 seconds holding time would be problematical in terms of some cheese production (notably cottage cheese, raw milk cheeses) and, in addition, was irrelevant for milk produced using a low temperature, micro-filtration process;
  • a register of Crohn's disease patients was being considered in Northern Ireland (to help enhance in

ANNEX I - Summary of points from the public question and answer session

1.1 Members of the public were invited to make statements or ask questions. Responses were made through the Chairman and, at his invitation, by ACMSF Members, Assessors and officials.

1.2 Dr Ed Komorowski (Dairy Industry Federation) noted that summary data from the FSA’s milk survey had been published but asked when the full report would be published. Dr Back (FSA) said that, whilst he could not offer a firm date, full data would be published as soon as possible, subject to competing priorities. However, in view of the great interest in the samples which were positive for MAP, it was hoped to extract the MAP information and make it available just after Christmas.

1.3 Dr Hilary Close (National Council of Women) stressed the importance of traceability across all foodstuffs, and not just in a microbiological food safety context (but also in relation to pesticides and chemicals). There was a strong European Union dimension and not purely in relation to food but also as regards taxes. Dr Close therefore wondered whether the ACMSF could put pressure on the FSA to consider further options for improving traceability. Dr Skinner (FSA) confirmed that the FSA was very concerned about traceability. It was being actively considered, and policy was being developed, by colleagues in the FSA’s Food Labelling and Standards (FLS) Division. There had been recent public discussion about these issues within the food labelling forum and other activities of FLS Division. The whole issue of traceability was being considered in Brussels.

1.4 Dr Andrews said that the difficulty with traceability was that it was data intensive. Moreover, that data had to be robust as the product moved through the food chain. It was important to decide, in the context of traceability, how far back down the food chain it was necessary to go. Was it, for example, sufficient to be able to trace back to an individual farm, or was it necessary to go back even further – for example, to an individual animal, or to an individual animal and its health history and any feeding regime which it had experienced throughout its life ? A case could be made for all of that information. To take the example of the contaminated lettuce discussed earlier in the meeting, was it sufficient simply to know where the lettuce came from, or to have information too about the part of the field in which it was grown, and the agricultural practices applied to that part of the field ? Manufacturers and retailers were very concerned about traceability and one of the difficulties facing the industry was that the systems for carrying all the data required to permit swift and accurate traceability currently did not exist. Some data management systems were being commercially developed and their use was being investigated very seriously by the food industry. But for any system to work, it was necessary for all parts of the supply chain to input all the required data at the correct time and into the correct part of the database. Some parts of the industry (eg. the potatoes and cereals sectors) already had very good traceability but it was currently less well developed elsewhere.

1.5 Mr Alan Long (Vegetarian Economy and Green Agriculture) asked whether the 2% of milk samples from the FSA survey which were positive for MAP were winter milk or summer milk. He had undertaken some work of his own, looking at the conditions of milking cows and other animals. This demonstrated an enormous difference between cows kept indoors, in cubicles particularly, and those kept outdoors. The milking process was inherently subject to contamination. Large numbers of animals were presented for slaughter and for milking in a filthy state. Dirty animals were cleaned up in some way before being milked but there was no evidence that any of the cleansing methods were fully effective. Farmers were often unsure of the types of disinfectant to use before and after milking. There was also the problem of the teat canal remaining open immediately after milking. The proper way of dealing with this was to put the cows out after milking into a loafing area with clean straw while the teat canal was closing up, thus avoiding infection through that route. There was a range of microorganisms which could cause health problems, and aerosols were an important route of infection. People could avoid risks from pathogenic microorganisms by avoiding cows’ milk and switching instead to soya milk. The ACMSF’s advice to the public should be that it was possible to avoid many of the difficulties which had been highlighted, by switching to these alternative products.

1.6 With regard to Mr Long’s seasonality question, Dr Back (FSA) said that information was available about when milk samples were taken. However, there were only about 10 positive samples, which made it very difficult to draw meaningful conclusions. Also, more than one year’s data would be needed to enable any valid view to be taken of possible seasonal effects.

1.7 Mr Alan Kennedy (PARA) congratulated the ACMSF on its open stance on the question of MAP and Crohn’s disease and on its precautionary approach. He supported the development of a strategy which he regarded as very comprehensive and appropriate for the solution of what was a very complex problem. Mr Kennedy hoped that there would be a timetable for the strategy, to enable checks to be made on progress. He also sought clarification on whether the 25 second holding time would be advisory or mandatory. Mr Kennedy said that the current scientific view in relation to Crohn’s disease and MAP was that genetic susceptibility was required and it seemed that Crohn’s sufferers might benefit from restricting their intake of dairy products to those which had been pasteurised for 25 seconds. However, this raised the question of how people could tell for how long milk had been pasteurised. The ACMSF could help by recommending that all milk should be appropriately labelled. Finally, Mr Kennedy mentioned beef as a possible exposure route for MAP. Cull cows from a Johne’s control programme could enter the food chain. A seriously clinically ill animal going into the food chain could have 1012-1013 bacteria, which would constitute a far higher source of exposure to MAP than exposure through milk. He wondered whether the ACMSF had any plans to address this issue.

1.8 As regards the question of the increased holding time, Dr Back confirmed that the minimum laid down in legislation was 15 seconds. It would be very difficult to get this changed to 25 seconds and would, in any event, require an EU approach. Dr Back confirmed that, once the strategy had been adopted, a timetable would be developed for its implementation. The Chairman confirmed that the ACMSF’s involvement with MAP had thus far been restricted to milk, and the meat exposure pathway had not been addressed. However, Professor Johnston said that clinical Johne’s disease traditionally appeared in older animals. The fact that, in the UK, only cattle under thirty months of age were slaughtered for human consumption, thus offered a measure of protection. In addition, clinically ill animals would be totally rejected at ante and post-mortem inspection and could not go for human consumption. Finally, animals ill with Johne’s disease should not be milked.

1.9 Mr Kennedy returned to the question of labelling. He thought that if Crohn’s disease sufferers, of which there were 80,000 in the UK, could reduce the risk of exposure to the organism by a simple labelling measure, that would be an enormous step forward. The Chairman invited FSA officials to think about this in terms of the development of the strategy and in the wider context.

1.10 Mr Alan Proctor (Zhitz International) said that he was a member of an organisation which advocated zero tolerance of diarrhoea. He welcomed the MAP strategy. He noted that the incidence of food poisoning, particularly due to Salmonella, had markedly reduced. However, despite increased pasteurisation times in some dairies, the incidence of Crohn’s disease was actually increasing. Department of Health data on hospital episodes showed it to be increasing by 7% p.a. The EU had already listed MAP as a pathogen. Mr Proctor drew attention to the conflicting advice given to Crohn’s sufferers (eg. on whether UHT milk was a safe option) and asked who was the authoritative source of advice on whether or not it was safe to drink milk.

1.11 The Chairman said that the ACMSF had, on the basis of a science-based approach to risk assessment, concluded that there was insufficient evidence available to justify saying that milk was unsafe to drink, or that people should change their dietary habits. In terms of special advice to Crohn’s sufferers, this was a matter for clinical advice. Dr Skinner (FSA) added that the Advisory Committee on Dangerous Pathogens had considered the question of whether a link existed between Crohn’s disease and MAP and concluded that the link was unproven. The European committee which considered the matter recently had reached a similar conclusion. The Chairman confirmed that that evidence had been taken into account by the ACMSF in reaching its own conclusions and recommendations. However, the ACMSF’s view was not dogmatic and would be changed if the scientific evidence changed. The Committee recognised that this was an area where there was continuing controversy.

1.12 Ms Sheila Lakes (Zhitz International) asked whether MAP was found in water.

1.13 Professor Hunter said that, in the research project with which he had been associated, bacteria of the M. avium complex had been found, but not MAP per se.