Fate of<i>Mycobacterium avium</i>subsp.<i>paratuberculosis</i>in Swiss Hard and Semihard Cheese Manufactured from Raw Milk

Spahr, U.; Schafroth, K.

doi:10.1128/aem.67.9.4199-4205.2001

Cited by 71 publications

(69 citation statements)

References 23 publications

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“…No previous study has shown the impact of culture medium on acid or thermal resistance of M. paratuberculosis. The study of Spahr and Schafroth investigating M. paratuberculosis survival in cheese used Middlebrook 7H9-OADC medium supplemented with 0.5% (vol/vol) glycerol (34). The thermal resistance of M. paratuberculosis had been previously reported but with widely different results for growth of the organism in different types of medium such as 7H9 medium (35), 7H9-ADC medium (30), 7H9-OADC medium (19,36,37), 7H9-OADC medium supplemented with 0.5% (vol/vol) glycerol (13), and WR-GD medium (18).…”

Section: Discussionmentioning

confidence: 99%

Variation in Resistance of Mycobacterium paratuberculosis to Acid Environments as a Function of Culture Medium

Sung

Collins

2003

Appl Environ Microbiol

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Acid resistance of Mycobacterium paratuberculosis was examined as a function of growth conditions (i.e., in vitro growth medium and pH). M. paratuberculosis was cultured in either fatty acid-containing medium (7H9-OADC) or glycerol-containing medium (WR-GD or 7H9-GD) at two culture pHs (pHs 6.0 and 6.8). Organisms produced in these six medium and pH conditions were then tested for resistance to acetate buffer at pHs 3, 4, 5, and 6 at 20°C. A radiometric culture method (BACTEC) was used to quantify viable M. paratuberculosis cell data at various acid exposure times, and D values (decimal reduction times, or the times required to kill a 1-log 10 concentration of bacteria) were determined. Soluble proteins of M. paratuberculosis grown under all six conditions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to identify proteins that may be associated with acid resistance or susceptibility. The culture medium affected growth rate and morphology: thin floating sheets of cells were observed in 7H9-OADC versus confluent, thick, waxy, and wrinkled pellicles in WR-GD. Culture medium pH affected growth rate (which was highest at pH 6.0), but it had little or no Mycobacterium paratuberculosis, also known as Mycobacterium avium subsp. paratuberculosis, is the cause of Johne's disease, a widespread chronic granulomatous inflammatory bowel disease of dairy cattle and other ruminants (5,6,40). Several reports indicate a significant association of M. paratuberculosis with a similar inflammatory bowel disease of humans called Crohn's disease (2,7,11,16,23,28). Whether this is a causal association remains controversial (17, 41).There are a number of routes for human exposure to M. paratuberculosis. Foods of animal origin (and dairy products in particular) have received the most attention. Consequently, the ability of M. paratuberculosis to resist heat (such as during pasteurization) and chemical factors important in food preservation (such as low pH and high salt concentration) has become important in the field of M. paratuberculosis research (13-15, 19, 30, 34, 36, 37).We previously reported rates of survival of M. paratuberculosis in a soft white Hispanic-style cheese made from M. paratuberculosis-spiked milk (37). The decimal reduction times (D values [i.e., times required for a 1-log 10 reduction in viable counts]) were 36.5 and 59.9 days for cheese made from heattreated and non-heat-treated M. paratuberculosis-spiked milk, respectively. Similar D values for M. paratuberculosis in Swiss hard (27.8 days) and semihard (45.5 days) cheeses were reported by Spahr and Schafroth (34).Low pH appeared to be one of the factors in cheese production that are important in affecting M. paratuberculosis survival (37). The present study was undertaken to further characterize acid resistance of M. paratuberculosis and determine the degree to which in vitro culture conditions affect the outcome of pH resistance studies. MATERIALS AND METHODSM. paratuberculosis strains. Three bovine M. paratuberculosis strai...

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Section: Discussionmentioning

confidence: 99%

Variation in Resistance of Mycobacterium paratuberculosis to Acid Environments as a Function of Culture Medium

Sung

Collins

2003

Appl Environ Microbiol

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“…The two most important factors contributing to the inactivation of bacterial pathogens during the 60-day curing process are low pH and high salt concentration (Spahr and Schafroth, 2001).…”

Section: Map In Cheesementioning

confidence: 99%

Detection methods for Mycobacterium avium subsp paratuberculosis in milk and milk products: a review

Slaná¹,

Paolicchi²,

Janštová³

et al. 2008

Vet. Med. - Czech

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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.

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“…This is mainly due to the detection of IS900-positive mycobacteria in tissues of Crohn's disease patients (9) and the observation of an extraordinary temperature resistance resulting in M. paratuberculosis not being fully inactivated by pasteurization temperatures (13,33) and surviving the cheese-manufacturing process (30).…”

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Development of a Peptide-Mediated Capture PCR for Detection of Mycobacterium avium subsp. paratuberculosis in Milk

et al. 2002

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Based on phage display technology, a peptide-mediated magnetic separation technique was developed to facilitate selective isolation of Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) from bulk milk of naturally infected dairy herds. Nine recombinant bacteriophages binding to M. paratuberculosis were isolated from a commercial phage-peptide library encoding random 12-mer peptides. Nucleotide sequencing revealed the deduced sequence of the binding peptides. One peptide with the sequence NYVIHDVPRHPA, designated aMP3, was chemically synthesized with an amino-terminal biotin residue attached via an amino-hexacarbonic acid spacer molecule. Paramagnetic beads coated with the phage or with peptide aMP3 enabled the capture of M. paratuberculosis from milk. Combining this peptide-mediated magnetic separation with an ISMav2-based PCR allowed the detection of M. paratuberculosis in artificially spiked milk down to a concentration of 10 1 ml ؊1 . Experiments using milk from naturally infected cows and bulk milk samples from infected herds demonstrated that the peptide-mediated capture PCR is sufficiently sensitive to detect single strong shedders in pooled milk samples. The method, for the first time, applies phage display technology to microbial diagnostics and has potential value as a completely standardizable tool for the routine M. paratuberculosis screening of bulk milk samples at acceptable costs.

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Fate ofMycobacterium aviumsubsp.paratuberculosisin Swiss Hard and Semihard Cheese Manufactured from Raw Milk

Cited by 71 publications

References 23 publications

Variation in Resistance of Mycobacterium paratuberculosis to Acid Environments as a Function of Culture Medium

Variation in Resistance of Mycobacterium paratuberculosis to Acid Environments as a Function of Culture Medium

Detection methods for Mycobacterium avium subsp paratuberculosis in milk and milk products: a review

Development of a Peptide-Mediated Capture PCR for Detection of Mycobacterium avium subsp. paratuberculosis in Milk

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