Cooking and drying as effective mechanisms in limiting the zoonotic effect of Mycobacterium bovis in beef

For this study 48 non-infected muscle, lymphatic and visceral bovine tissue samples were collected from an approved red meat abattoir and spiked with 8 x 10(7) cfu/ml of M. bovis. The different spiked samples were subjected to cooking and drying (drying through the process of biltong-making) processes in a controlled laboratory environment. Mycobacterial isolates confirmed as M. bovis by means of polymerase chain reaction (PCR) were observed in 17 of a total of 576 samples that were exposed to the secondary processing method of cooking. The study showed that not only can M. bovis survive the cooking process but the survival of the bacterium will be determined by its unique adaptive changes to the surrounding composition of the environment. The results for the samples exposed to the drying process (n = 96) did not show any growth, suggesting that the process of biltong production as used in this study is likely to render infected meat safe for human consumption.