NR APBP
AU anonym
TI Contamination of beef carcases with brain tissue - research results published
QU BSE Enforcement Bulletin - November 1999 Issue 40, Seite 4
IA http://www.maff.gov.uk/animalh/bse/bse-publications/enforce/bseeb40.pdf
VT
A MAFF-funded research project by a team at Bristol University found that some stunning and slaughter procedures might cause cattle carcases to be contaminated by brain tissue. However, following a review of the results, the Spongiform Encephalopathy Advisory Committee (SEAC) advised that there is no reason to change UK slaughter methods. An article describing the results of the research project was published in the Veterinary Record of 16 October 1999.
The researchers were looking for signs of brain tissue in the large blood vessels draining the head of cattle which had been stunned using various different methods. They found brain tissue in blood of only one animal which had been stunned by penetrative captive bolt - a method used in the UK. This was one of sixteen animals which had been stunned using a penetrative captive bolt gun, followed by pithing. None of fifteen animals stunned by penetrative captive bolt without subsequent pithing showed any sign of brain material in their blood.
In addition, brain tissue was found in four out of fifteen animals stunned with a penetrating captive bolt gun which introduces air at high pressure into the skull. This equipment is not used in the UK but is used in the USA. Negative results were recorded for a further fourteen animals stunned using a non-penetrating concussive gun.
The article concludes that
- dissemination of brain tissue in the blood can occur with the use of a penetrating captive bolt gun, followed by pithing; and
- the timing of the appearance of brain material in the blood is such that it will have passed into, and possibly through, the lungs before the animal would normally have been bled.
This finding raises possible food safety concerns because, if traces of brain tissue can be transported via the blood stream to the edible parts of the carcase, there could be implications for human health in relation to BSE.
SEAC discussed preliminary results of this work with the researchers concerned (see public summary of 9 November 1998 meeting in Bulletin #29) and subsequently reviewed a draft of the article. Their advice is that there is no reason on the basis of current data to change the common UK practices of stunning and pithing during slaughter of cattle. SEAC's reasoning was that
- the finding of brain tissue in the venous blood in one of a group of sixteen cattle slaughtered by penetrating captive bolt pistol and subsequent pithing provides insufficient data to give an accurate assessment of the frequency of this occurrence;
- the research does not show whether or not neural tissue reached the arterial circulation in the single positive animal;
- with the OTMS in place, the very low number of infected animals at the late stage of the incubation period entering the food chain means that there is no need to alter current slaughter practices.
Ministers have been informed of this research and have accepted SEAC's advice.
What is pithing?
Pithing is the insertion of a rod into the brain through the hole made by the captive bolt. It destroys brain tissue and speeds up brain death. Pithing is carried out before hoisting the carcase to reduce the involuntary kicking actions of the stunned animal which can be a health and safety risk to slaughterhouse staff.
Details of the MAFF research programme into BSE and related diseases can be found on the MAFF website at: http://www.maff.gov.uk/animalh/bse/index.htm
IN Das SEAC prüfte die Ergebnisse der vom MAFF geförderten Studie von Anil et al. und sah dennoch im November 1999 keinen Grund für eine Änderung der Schlachtmethoden im Vereinigten Königreich. Es plädierte also noch Ende 1999 gegen die Änderung einer offensichtlich gefährlichen Praxis, nur weil das vorhandene Datenmaterial noch keine genaue Abschätzung des Risikos erlaubte. Das ist das unveränderte Verständnis von vorbeugendem Verbraucherschutz des SEAC und dies zeigt, dass das SEAC immer noch nichts aus seinen Fehlern gelernt hat. Anstatt sicherheitshalber bis zum Beweis seiner Ungefährlichkeit zumindest auf das zusätzliche Zerstören des Stammhirnes zu verzichten, warten sie tatenlos auf Daten für eine Kalkulation des Ausmaßes der bestehenden Gefahr für die britische Bevölkerung. Während Anil et al. mit ihren Daten plausibel machen, dass mikroskopisch kleines Hirngewebe genügend Zeit für ein Passieren der Lunge und damit für die Kontamination von Muskelfleisch haben, weist das SEAC wie gehabt auf das Fehlen eines endgültigen Beweises hin und wiegelt ab. Seine Begründung ist, dass wegen der Schlachtung vor dem 31. Lebensmonat nur sehr wenige BSE-infizierte Rinder das Endstadium ihrer Krankheit und damit die Phase höchster Infektiosität im Gehirn erreichen und daß die zusätzliche Zerstörung des Gehirnes die Gefahr für das Schlachthofpersonal durch unwillkürliche Bewegungen der Schlachttiere reduziert. Das SEAC gibt nur 4 der 5 Fälle wieder, in denen die Autoren der Studie Hirnmaterial im Blut pneumatisch betäubter Rinder fand. Außerdem behauptet das SEAC entgegen der Aussage des Herstellers, die Luft injizierenden Bolzenschußapparate würden im Vereinigten Königreich nicht eingesetzt.
SP englisch