Linked Life Data

20097817

Source:http://linkedlifedata.com/resource/pubmed/id/20097817

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2010-3-5
pubmed:abstractText
Thermal inactivation experiments were carried out to assess the utility of a recently optimized phage amplification assay to accurately enumerate viable Mycobacterium avium subsp. paratuberculosis cells in milk. Ultra-heat-treated (UHT) whole milk was spiked with large numbers of M. avium subsp. paratuberculosis organisms (10(6) to 10(7) CFU/ml) and dispensed in 100-microl aliquots in thin-walled 200-microl PCR tubes. A Primus 96 advanced thermal cycler (Peqlab, Erlangen, Germany) was used to achieve the following time and temperature treatments: (i) 63 degrees C for 3, 6, and 9 min; (ii) 68 degrees C for 20, 40, and 60 s; and (iii) 72 degrees C for 5, 10, 15, and 25 s. After thermal stress, the number of surviving M. avium subsp. paratuberculosis cells was assessed by both phage amplification assay and culture on Herrold's egg yolk medium (HEYM). A high correlation between PFU/ml and CFU/ml counts was observed for both unheated (r(2) = 0.943) and heated (r(2) = 0.971) M. avium subsp. paratuberculosis cells. D and z values obtained using the two types of counts were not significantly different (P > 0.05). The D(68 degrees C), mean D(63 degrees C), and D(72 degrees C) for four M. avium subsp. paratuberculosis strains were 81.8, 9.8, and 4.2 s, respectively, yielding a mean z value of 6.9 degrees C. Complete inactivation of 10(6) to 10(7) CFU of M. avium subsp. paratuberculosis/ml milk was not observed for any of the time-temperature combinations studied; 5.2- to 6.6-log(10) reductions in numbers were achieved depending on the temperature and time. Nonlinear thermal inactivation kinetics were consistently observed for this bacterium. This study confirms that the optimized phage assay can be employed in place of conventional culture on HEYM to speed up the acquisition of results (48 h instead of a minimum of 6 weeks) for inactivation experiments involving M. avium subsp. paratuberculosis-spiked samples.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1098-5336
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
76
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1777-82
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Rapid assessment of the viability of Mycobacterium avium subsp. paratuberculosis cells after heat treatment, using an optimized phage amplification assay.
pubmed:affiliation
Institute of Agri-Food and Land Use, School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom.
pubmed:publicationType
Journal Article, Comparative Study, Evaluation Studies