On-line version ISSN 2224-9435
J. S. Afr. Vet. Assoc. vol.82 n.1 Cape Town Jan. 2011
TO THE EDITOR AAN DIE REDAKTEUR
A reply to the letter of Professor Viroj Wiwanitkit
The valued comments from Prof. Wiwanitkit echo the self-criticism of the authors on the topic. The study aimed to investigate the survival potential of M. bovis in dried meat. The most effective or ideal food preparation method was not discussed but was recommended for further study. It must be emphasised, however, that no pathogens - only non-tuberculous mycobacteria - were isolated from the processed samples.
In the opinion of the authors, the size and volume of the samples affected the ability of the processes to destroy the pathogen. A study to investigate different processes is, therefore, currently in the proposal phase (focusing on food density, temperature, exposure time and Aw) to test this hypothesis.
Biltong is a dry food with a high Aw (according to taste) preferred by some consumers. Carpaccio is raw, thinly sliced game meat and this undercooked game fillet is served in many local restaurants and lodges. Such foods are a delicacy in South Africa and avoidance of it, especially in a protein-deficient continent, is therefore rightfully correctly perceived to be unacceptable.
Prof. Wiwanitkit is advised to obtain a previous publication, namely that of M Van Der Merwe, J L Bekker, P Van Der Merwe and A L Michel on 'Cooking and drying as effective mechanisms in limiting the zoonotic effect of Mycobacterium bovis in beef' (Journal of the South African Veterinary Association (2009) 80: 142-145). In that study, the survival of M. bovis was investigated in spiked approved beef and, alarmingly enough, it survived the cooking and drying processes.
We would like to invite Prof. Wiwanitkit to contact me personally to discuss future work.
M van der Merwe
Department of Environmental Health, Tshwane University of Technology