M01022: Methods for the determination of Mycobacterium bovis within edible tissues from TB-suspect cattle following slaughter and salvage
Friday 5 September 2003
This research project aims to determine whether M. bovis can be found in cattle meat.
Background
This project aimed to provide information on the likelihood of Mycobacterium bovis contamination of meat that might otherwise be salvaged from bovine tuberculosis (TB) 'reactor' animals and proceed to the food chain. Lymphatic tissue samples were tested for M. bovis using traditional culture PCR methods.
Results and findings
The main findings by the traditional culture method are that:
- Of the 153 carcasses sampled, 110 (71.9%) had no visible lesions (NVL) and 43 (28.1%) had visible lesions (VL); 25 of these had 1 lesion; 14 had 2 lesions; 4 had 3 lesions.
- thus 5 of 110 animals (4.5%) with NVL yielded viable M. bovis from carcass or edible offal lymphatic tissue.
- 1 of 25 animals (4%) with a single VL and 1 of 18 animals (5.5%) with 2 or more VL also yielded viable M. bovis from carcass or edible offal lymphatic tissue.
- A percentage of the samples were also cultured by a second, more experienced, laboratory and good agreement was achieved.
Although initially indicating a much higher incidence of positive samples compared to traditional culture, the PCR method could not be validated. Therefore, these results were not taken into account.
Results from the culture-based study were included in a report to the Advisory Committee on the Microbiological Safety of Food (ACMSF) who concluded that any risk to public health was adequately managed by current controls, see ACMSF minutes: 18 September 2003