Human exposure to Mycobacterium paratuberculosis via pasteurised milk: a modelling approach
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Published on: June 30, 2019
M J Nauta1, J W van der Giessen
1Microbiological Laboratory for Health Protection, National Institute of Public Health and the Environment, Bilthoven, The Netherlands.
Abstract:
Paratuberculosis is a disease of cattle caused by infection with Mycobacterium paratuberculosis, and it has been suggested that this bacterium may also play a role in the aetiology of Crohn's disease in humans. M paratuberculosis is shed in the milk and may be able to survive pasteurisation. Therefore, people may be exposed to it by the consumption of pasteurised milk. The risk of such exposure has been analysed using a modelling approach and the model has been used to evaluate the effects of intervention measures at different points in the potential route of transmission. On the basis of data from the literature and expert opinion, an initial point estimate of the exposure level of about 0-5 cfu/litre pasteurised milk was derived, mainly due to milk from clinically affected animals. The model indicates the need for quantitative data on variations in the shedding rates of M paratuberculosis in faeces and milk, and the levels of faecal contamination of milk. Such data are essential for a proper analysis of potential exposure, and may result in a 100-fold increase in the estimated median level of exposure.
Insights
Mycobacterium paratuberculosis, a cause of paratuberculosis in cattle, may contribute to Crohn's disease in humans. Exposure risk from pasteurized milk is analyzed, highlighting data gaps for accurate risk assessment.
Area of Science:
- Veterinary Medicine
- Human Gastroenterology
- Food Safety
Background:
- Paratuberculosis is a cattle disease caused by Mycobacterium paratuberculosis.
- This bacterium is implicated in the human disease Crohn's disease.
- M. paratuberculosis can be shed in milk and may survive pasteurization.
Purpose of the Study:
- To analyze the risk of human exposure to M. paratuberculosis through pasteurized milk consumption.
- To evaluate the effectiveness of intervention measures along the transmission route.
- To identify critical data gaps for a comprehensive exposure analysis.
Main Methods:
- A quantitative modeling approach was employed.
- Data were sourced from literature reviews and expert opinions.
- The model assessed exposure levels and intervention impacts.
Main Results:
- An initial exposure estimate of approximately 0.5 cfu/litre in pasteurized milk was derived, primarily from infected animals.
- The model identified a need for quantitative data on shedding rates and milk contamination.
- Addressing these data gaps could potentially increase the estimated median exposure by 100-fold.
Conclusions:
- Human exposure to M. paratuberculosis via pasteurized milk is a plausible concern.
- Accurate risk assessment requires more quantitative data on bacterial shedding and contamination.
- Intervention strategies need to be informed by robust data for effective risk mitigation.
