Volume 6: Human Health, 1989-96
8. Development of guidance on occupational risks from BSE and other TSEs
1991
Mr North requests information on slaughterhouses

8.113 The meeting in November was cancelled because of snowstorms, and on 15 February 1991 Dr Gompertz minuted members of the Committee to say that he had now received contributions on all the 17 agreed zoonoses. He attached a draft of 'The Occupational Zoonoses' guidance, and sought comments on it prior to finalising it for publication. ¹

8.114 The second meeting of the CDTFZ & BSE was held on 15 March 1991. ² On BSE, Mr Lister, Mr North and Mr Greaves reported that SEAC 'would be dealing with little of interest to this Group and that it would therefore not be appropriate to have an observer on the Committee'. However, Mr Lister would receive papers and keep an eye on developments. (Five years later, in 1996, HSE was granted observer status on SEAC; see paragraph 8.148).

8.115 Mr North said that a small NIG Working Group might be looking at practices in slaughterhouses. The group also discussed briefly the need for guidance for the rendering industry. It was agreed that Mr North and Dr Matthews would consider this further using information available from MAFF. Mr North might accompany MAFF Inspectors on a visit to a rendering plant. Mr Lister reported that the ACDP had created a Working Group on TSEs which might be looking at BSE. (The ACDP Group's deliberations are discussed later in this chapter.)

Mr North requests information on slaughterhouses

8.116 On 3 July 1991, Mr North wrote to Dr Wood (University of Bristol, Animal Science Section) to ask for a discussion and visit to their in-house model slaughterhouse. ³ Mr North explained his interest in deep penetrating wounds and cross-contamination and in pinpointing any particular high-risk activities.

8.117 Mr North enclosed 'Guidance Note 5' issued the previous year and explained:

Whilst this guidance provides general assurance and sets out the general precautions it was felt to be prudent to at least identify which particular slaughterhouse activities might be associated with any hazard to employees in the event that evidence comes to light that BSE is transmissible to man. In that, hopefully unlikely, eventuality we would like to be in a position to know which activities carried a risk and to have considered possibilities of different work methods to alleviate that risk. Of course employees are already trying to avoid the more acute penetrating injury in the first place but such accidents do regrettably occur and if the risk to their health was much greater than the immediate physical injury then it may indicate that a higher standard of safeguards may be appropriate. These are the areas I would wish to explore.

8.118 On 4 July 1991, Dr Wood responded confirming that he would be pleased to assist in defining which slaughterhouse practices were potentially hazardous. ⁴

8.119 At the next meeting of the CDTFZ & BSE, held on 7 October 1991, Mr North reported on his continuing investigations regarding deep cut hazards for slaughterhouse workers. ⁵ Splitting the head of the animal to remove the brain and splitting the spinal column appeared to pose the greatest risk and Mr North was asked to convey to slaughterers the need to continue taking all precautions. He reported that he was working on guidance for the knackering and rendering industries. The meeting agreed that guidance on handling infected carcasses in hunt kennels and maggot farms was also required.

8.120 At the conclusion of the meeting the Chairman suggested the Committee should remain in existence 'as a forum for discussions of developments' and meet again in March 1992.

8.121 On 28 November 1991, Food NIG issued a minute to HM Inspectors of Factories and Employment Medical Advisers (EMAs) entitled 'Application of COSHH ⁶ to microbiological hazards in the meat industry and updates in knackers, renderers and BSE'. ⁷ This stated:

The purpose of this minute is to give Inspectors and EMAs early information of guidance which the NIG has cleared through the HSE/Meat Trades Joint Working Party and the HSE Cross Divisional Taskforce on Zoonoses and BSE; and of precautions advocated in relation to knackers, renderers and slaughterhouses in relation to Zoonoses BSE.

8.122 The guidance stressed that Inspectors should press for surveillance by employers to assist them to determine if there was a hazard or if there was adequate control. Until there was adequate information about prevalence, most of the control measures required were likely to be general and personal hygiene ones. It also stated that because the NIG had received enquiries, the present advice was an advance notice of a forthcoming HSE/Meat Trades Joint Working Party Guidance Note and Operational Circular (OC) drawing attention to the whole series of such guidance notes. ⁸

8.123 On knackers and renderers it stated:

The NIG has completed a survey of microbiological hazards in the knackering and rendering industries. This survey tended to show that microbiological hazards should be adequately controlled by good process and personal hygiene. Because prohibited offal is handled by knackers and renderers, the processes were also examined in relation to possible occupational hazards from BSE. As a result the NIG will be pressing the industry not to scoop brains out of split bovine heads by hand - because of the risk of a deep cut from bone fragments contaminated with a high concentration of the BSE agent from the brain.

. . .

The NIG has recently carried out a further analysis of slaughterhouse activities to identify which processes might pose a particular risk of such deep inoculation and of possible control measures. The processes appear to be the use of the depithing rod, removal of the brain after splitting the head and (possibly) splitting the spinal column. MAFF have advised that the vast majority of bovine carcases going through an abattoir come from animals that will not have been exposed to BSE through feed (mostly because they have been reared post 1988) but that cull cows (ie adult cattle) will have been exposed at a time when the challenge dose in feed was at its maximum (early 1988). A few of these cull cows may be handled at any abattoir but a few slaughterhouses may specialise in them (eg for certain specialised products such as beefburgers). For these, the 3 or 4 years which has intervened since 1988 would mean that the BSE agent was in a particularly concentrated state in their brain tissue. So far the agent has not been identified in any part of the prohibited offal other than the brain tissue but as further time develops it is expected the agent would spread. Therefore, there is a particular need when handling such older cattle to take additional prudent precautions to avoid contamination with (for the present) brain tissue.

Such prudent precautions might include not using the pithing rod or disinfecting it on withdrawal from the brain. Animal welfare considerations should also be considered however as pithing is designed to ensure that no pain is felt if the stunning effect wears off too quickly.

Similarly, splitting of bovine heads should be discouraged in slaughterhouse premises (around 80% of slaughterhouses do not split heads now). If heads are to be split and brains removed then special tools should be used for brain removal rather than risk jagging the hand on sharp bone fragments with the risk of BSE agent contamination . . .

It is more difficult to identify precautions which could be taken against deep cuts and contamination whilst splitting the spinal column. However, at present this is not such a priority as no BSE agent has yet been found there. ⁹