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

A.L. Michel,M. Van der Merwe,P. Van der Merwe,J.L. Bekker

doi:10.4102/jsava.v80i3.189

Abstract

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.

Highlights

The World Health Organisation (WHO) reported in 2004 that 14.6 million people had active tuberculosis with 9 million new cases per annum[27]
polymerase chain reaction (PCR) amplification of single bacterial colonies confirmed them as M. bovis
In the samples decontaminated with hydrochloric acid (HCI) and cooked for 10 and 20 minutes respectively, M. bovis was only detected in lymph node and muscle samples

Summary

Introduction

The World Health Organisation (WHO) reported in 2004 that 14.6 million people had active tuberculosis with 9 million new cases per annum[27]. The potential zoonotic importance of M. bovis infection in an extremely wide host spectrum including domestic animals, wildlife and humans was cited by other researchers as a cause of public health concern in Africa[2,5,12]. The WHO reported in 1993 that aCity of Tshwane Municipality, PO Box 1401, Lyttelton, Centurion, 0140 South Africa. BDepartment Environmental Health, Tshwane University of Technology, Private Bag X680, Pretoria, 0001 South Africa. CDirectorate Animal Health, Department of Defence, Private Bag X11, Noordbrug, 2522 South Africa. DARC-Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort, 0110 South Africa. Present address: Department Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X4, Onderstepoort, 0110 South Africa

Methods

Results

Conclusion