Investigation into Mycobacterium Avium Complex and its Presences in Australian Commercially Available Pasteurised Milk

Author: Tanya Alexandra Caro Tohme

Caro Tohme, Tanya Alexandra, 2016 Investigation into Mycobacterium Avium Complex and its Presences in Australian Commercially Available Pasteurised Milk , Flinders University, School of the Environment

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Mycobacterium avium complex (MAC) has been identified as the cause of John’s disease in animals and a pathogenic bacteria to humans causing pulmonary infections, cervical lymphadenitis, cutaneous infections and possibly Crohn’s disease. John’s disease and Crohn’s disease have several similarities, which has researcher lead to believe that MAC could be a contributing factor that causes Crohn’s disease. MAC is found in the environment, mainly in soil and water. It is transferred through faeces and milk. Studies around the world have reported the presence of MAC in milk and its transmission to humans through ingestion. In addition, it has been shown that in some cases, the bacteria has survived pasteurisation and has been found in commercially available milk, making it unsafe for consumption. In Australia, there is a high prevalence of Crohn’s disease and there are no previous studies done on the presence of MAC in commercially available Australian milk. 14 different milks were tested for MAC through qPCR method and tested again after a 3-week incubation period. In addition, milk was artificially spiked with MAC and tested after submitting the spiked samples through two pasteurisation processes. All the result were negative for MAC. In conclusion, MAC was not detected in milk either because it is non-existent in milk or it is in very low quantities making not enough to reach detection levels. Further investigation is required in larger number of milk samples and in pasteurisation efficiency against MAC survival.

Keywords: Mycobacterium avium complex, Crohn's disease, Quantitative Polymerase Chain Reaction (qPCR) Testing, Mycobacterium avium paratuberculosis,commercially available pasteurised milk,
Subject: Environmental Health thesis

Thesis type: Masters
Completed: 2016
School: School of the Environment
Supervisor: Harriet Whiley