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Published on: February 15, 2012
Thermal tolerance of Mycobacterium paratuberculosis
1Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison 53706, USA.
Applied and Environmental Microbiology
|March 21, 1998
Summary
Mycobacterium paratuberculosis exhibits significant thermal tolerance, with higher D values than other pathogens. This suggests it may survive high-temperature, short-time pasteurization, posing a public health risk.
Area of Science:
- Food Microbiology
- Bacteriology
- Public Health
Background:
- Mycobacterium paratuberculosis is an important veterinary and potential human pathogen.
- Understanding its thermal resistance is crucial for food safety and public health.
Purpose of the Study:
- To determine the thermal resistance (D values) of human and bovine strains of Mycobacterium paratuberculosis.
- To compare thermal tolerance in different menstrua (milk and lactate solution) and temperatures.
- To assess the implications for pasteurization efficacy.
Main Methods:
- Decimal reduction times (D values) were determined for M. paratuberculosis strains in milk and lactate solution across a temperature range (62-71°C).
- Radiometric culture method (BACTEC) was used for quantifying viable organisms.
- Thermal death curves were analyzed for linearity and quadratic relationships.
Main Results:
- Human and bovine M. paratuberculosis strains showed varying D values depending on the menstruum and strain passage history.
- Clinical strains demonstrated lower D values than the laboratory strain.
- M. paratuberculosis exhibited higher thermal tolerance compared to Listeria, Salmonella, Coxiella, and Mycobacterium bovis.
Conclusions:
- Mycobacterium paratuberculosis possesses significant heat resistance, potentially surviving standard pasteurization conditions.
- The findings support the concern that M. paratuberculosis can persist through high-temperature, short-time pasteurization.
- This highlights the need for stringent pasteurization protocols to ensure milk safety.
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