Detection methods for Mycobacterium avium subsp. paratuberculosis in milk and milk products: a review (original) (raw)
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Detection methods for Mycobacterium avium subsp paratuberculosis in milk and milk products: a review
Veterinární Medicína
Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of paratuberculosis, a disease with considerable economic impact, principally on dairy cattle herds. Animals with paratuberculosis shed viable MAP especially in their milk, faeces and semen. MAP may have a role in the development of Crohn's disease in humans via the consumption of contaminated milk and milk products. The current methods of milk pasteurization are not sufficient to kill all MAP cells present in milk and MAP has been cultured from raw or pasteurized milk and isolated from cheese. The purpose of the present study was to review the different methods used for detection of MAP in milk and milk products. We analyze the current methods for direct or non direct identification of MAP and culture and molecular biology methods that can be applied to milk and milk products.
Journal of Microbiological Methods, 2008
A possible mode of transmission for the ruminant pathogen Mycobacterium avium subsp. paratuberculosis (MAP) from cattle to humans is via milk and dairy products. Although controversially, MAP has been suggested as the causative agent of Crohn's disease and its presence in consumers' milk might be of concern. A method to detect MAP in milk with real-time PCR was developed for screening of bulk tank milk. Pellet and cream fractions of milk were pooled and subjected to enzymatic digestion and mechanical disruption and the DNA was extracted by automated magnetic bead separation. The analytical sensitivity was assessed to 100 organisms per ml milk (corresponding to 1-10 CFU per ml) for samples of 10 ml. The method was applied in a study of 56 dairy herds to compare PCR of farm bulk tank milk to culture of environmental faecal samples for detection of MAP in the herds. In this study, 68% of the herds were positive by environmental culture, while 30% were positive by milk PCR. Results indicate that although MAP may be shed into milk or transferred to milk by faecal contamination, it will probably occur in low numbers in the bulk tank milk due to dilution as well as general milking hygiene measures. The concentration of MAP can therefore be assumed to often fall below the detection limit. Thus, PCR detection of MAP in milk would be more useful for control of MAP presence in milk, in order to avoid transfer to humans, than for herd prevalence testing. It could also be of value in assessing human exposure to MAP via milk consumption. Quantification results also suggest that the level of MAP in the bulk tank milk of the studied Danish dairy herds was low, despite environmental isolation of MAP from the herds.
Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi
Mycobacterium avium subsp paratuberculosis (MAP), excreted in the feces and milk, is reported to be not easily inactivated by pasteurization and thermal treatments as other bacteria infecting humans and animals do. The D values of all MAP strains tested were considerably higher than those published for other pathogens. Culturing techniques for this organism are labor intensive. Although an increasing amount of scientific evidence suggests that this organism can be responsible for at least some cases of Crohn's disease (CD), there is controversy about MAP being a cause of CD in humans. In general, although some studies have described an association between the presence of MAP and CD, the role of Mycobacterium species and MAP in the etiology of this human disease remains unestablished. Although published reports indicate that it may not be completely inactivated by pasteurization of milk, the effectiveness of increasing the time or temperature in the pasteurization process has not...
Mycobacterium Avium Subspeciae Paratuberculosis Identification in Milk by Means of IS900 PCR
Macedonian Journal of Animal Science, 2012
Between the numerous emerging pathogens, Mycobacterium avium subsp. paratuberculosis (MAP) reports a primary interest in its detection for its possible correlation with Crohn’s Disease in man (5). Milk and its subproducts may be very important in transmitting Mycobacterium avium subsp. paratuberculosis. The potential sanitary risk is related to the germ capacity in surviving to routine pasteurization treatments (1). These study objectives were the determination and the optimization of DNA extraction and purification assays to the direct Mycobacterium avium subsp. paratuberculosis (MAP) detection in milk, by means of PCR. The obtained results with the applied method are based in the milk and its subproducts chain inspective and control actions, relating to the increasing paratuberculosis etiological agent presence and the potential zoonotic transmitting.
International Journal of Dairy Technology, 2001
Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease in cattle and other ruminants and has been implicated as a possible cause of Crohn's disease in humans. The organism gains access to raw milk directly through excretion into the milk within the udder, and indirectly through faecal contamination during milking. MAP has been shown to survive commercial pasteurization in naturally infected milk, even at the extended holding time of 25 s. Pasteurized milk must therefore be considered a vehicle of transmission of MAP to humans. Isolation methods for MAP from milk are problematical, chiefly because of the absence of a suitable selective medium. This makes food surveillance programs and research on this topic difficult. The MAP problem can be addressed in two main ways: by devising a milk-processing strategy that ensures the death of the organism; and/or strategies at farm level to prevent access of the organism into raw milk. Much of the research to date has been devoted to determining if a problem exists and, if so, the extent of the problem. Little has been directed at possible solutions. Given the current state of information on this topic and the potential consequences for the dairy industry, research is urgently needed so that a better understanding of the risks and the efficacy of possible processing solutions can be determined.
Foodborne Pathogens and Disease, 2010
Paratuberculosis, or Johne's disease, is caused by Mycobacterium avium subsp. paratuberculosis (Map), and it generates great economic losses for the dairy industry worldwide. In humans, Map has been associated with Crohn's disease. Mexico has unknown paratuberculosis prevalence, and yet, control programs have not been applied. This study aimed to determine the presence of Map in milk samples from seropositive goats and cows and bulk tank milk samples from herds previously designated Map-infected using indirect enzyme-linked immunosorbent assay. Map DNA was detected in 100% of the bulk tank milk samples of 14 bovine herds and 3 caprine flocks using a modified insertion sequence 900 polymerase chain reaction (PCR). Additionally, Map DNA was detected in 100% of the individual milk samples from 10 cows and 8 goats. Further, based on the findings of the experimental insertion sequence 900 PCR assessment, evaluation of bulk tank and individual milk samples through a type-specific PCR was performed, which confirmed our previous findings and revealed that 56.25% cow and 63.63% goat milk had concurrent infections of the C, I, and S types. Out of 14 bulk tank milk samples, 10 had viable mycobacteria. Paratuberculosis was detected at a high frequency in cow and goat milk, which suggests that raw milk ingestion represents a potential risk of Map infection.
Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire, 2009
Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of Johne's disease in cattle and other farm ruminants, and is also a suspected pathogen of Crohn's disease in humans. Development of diagnostic methods for MAP infection has been a challenge over the last few decades. The objective of this study was to investigate the relationship between different methods for detection of MAP in milk and fecal samples. A total of 134 milk samples and 110 feces samples were collected from 146 individual cows in 14 MAP-infected herds in southwestern Ontario. Culture, IS900 polymerase chain reaction (PCR) and nested PCR methods were used for detecting MAP in milk; results were compared with those of fecal culture. A significant relationship was found between milk culture, direct PCR, and nested PCR (P < 0.05). The fecal culture results were not related to any of the 3 assay methods used for the milk samples (P > 0.10). Although fecal culture showed a higher sensitiv...