Heat tolerance of dairy lactococcal c2 phages

Cecilie Lykke Marvig Nielsen; Aideh Basheer; H. Neve; K.J. Heller; Susanne Knøchel; Finn Kvist Vogensen

Abstract

Nine Lactococcus lactis c2 phages propagated on different hosts were screened for thermal resistance in skimmed milk. Pronounced variations in thermal resistance were found. Three phages displayed high sensitivity towards heat resulting in >8 log reductions after 70 °C for 5 min, whereas the most thermal resistant phages required 80 °C for 5 min to obtain the same reduction. Inactivation kinetics were determined for a thermo-sensitive and a thermo-resistant phage at 60-70 °C and 65-78 °C, respectively, using a submerged-coil system with extremely short heating-up times. Inactivation followed first-order kinetics with correlation coefficients of 0.96-0.99. D₇₀-values of 12 s and 16.6 min were calculated for the most sensitive and resistant phage, respectively. Release of phage DNA from capsids, and disintegration of phage heads and tails were among the first morphological changes observed for moderately thermal inactivated lysates (15% phage inactivation) of the heat tolerant phage P635.

Original language	English
Publication date	Aug 2011
Number of pages	1
Publication status	Published - Aug 2011
Event	9th Symposium on Food Microbiology - Helsingør, Denmark Duration: 12 May 2011 → 13 May 2011

Conference

Conference	9th Symposium on Food Microbiology
Country/Territory	Denmark
City	Helsingør
Period	12/05/2011 → 13/05/2011

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title = "Heat tolerance of dairy lactococcal c2 phages",

abstract = "Nine Lactococcus lactis c2 phages propagated on different hosts were screened for thermal resistance in skimmed milk. Pronounced variations in thermal resistance were found. Three phages displayed high sensitivity towards heat resulting in >8 log reductions after 70 °C for 5 min, whereas the most thermal resistant phages required 80 °C for 5 min to obtain the same reduction. Inactivation kinetics were determined for a thermo-sensitive and a thermo-resistant phage at 60-70 °C and 65-78 °C, respectively, using a submerged-coil system with extremely short heating-up times. Inactivation followed first-order kinetics with correlation coefficients of 0.96-0.99. D70-values of 12 s and 16.6 min were calculated for the most sensitive and resistant phage, respectively. Release of phage DNA from capsids, and disintegration of phage heads and tails were among the first morphological changes observed for moderately thermal inactivated lysates (15% phage inactivation) of the heat tolerant phage P635.",

author = "Nielsen, {Cecilie Lykke Marvig} and Aideh Basheer and H. Neve and K.J. Heller and Susanne Kn{\o}chel and Vogensen, {Finn Kvist}",

year = "2011",

month = aug,

language = "English",

note = "9th Symposium on Food Microbiology ; Conference date: 12-05-2011 Through 13-05-2011",

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TY - ABST

T1 - Heat tolerance of dairy lactococcal c2 phages

AU - Nielsen, Cecilie Lykke Marvig

AU - Basheer, Aideh

AU - Neve, H.

AU - Heller, K.J.

AU - Knøchel, Susanne

AU - Vogensen, Finn Kvist

PY - 2011/8

Y1 - 2011/8

N2 - Nine Lactococcus lactis c2 phages propagated on different hosts were screened for thermal resistance in skimmed milk. Pronounced variations in thermal resistance were found. Three phages displayed high sensitivity towards heat resulting in >8 log reductions after 70 °C for 5 min, whereas the most thermal resistant phages required 80 °C for 5 min to obtain the same reduction. Inactivation kinetics were determined for a thermo-sensitive and a thermo-resistant phage at 60-70 °C and 65-78 °C, respectively, using a submerged-coil system with extremely short heating-up times. Inactivation followed first-order kinetics with correlation coefficients of 0.96-0.99. D70-values of 12 s and 16.6 min were calculated for the most sensitive and resistant phage, respectively. Release of phage DNA from capsids, and disintegration of phage heads and tails were among the first morphological changes observed for moderately thermal inactivated lysates (15% phage inactivation) of the heat tolerant phage P635.

AB - Nine Lactococcus lactis c2 phages propagated on different hosts were screened for thermal resistance in skimmed milk. Pronounced variations in thermal resistance were found. Three phages displayed high sensitivity towards heat resulting in >8 log reductions after 70 °C for 5 min, whereas the most thermal resistant phages required 80 °C for 5 min to obtain the same reduction. Inactivation kinetics were determined for a thermo-sensitive and a thermo-resistant phage at 60-70 °C and 65-78 °C, respectively, using a submerged-coil system with extremely short heating-up times. Inactivation followed first-order kinetics with correlation coefficients of 0.96-0.99. D70-values of 12 s and 16.6 min were calculated for the most sensitive and resistant phage, respectively. Release of phage DNA from capsids, and disintegration of phage heads and tails were among the first morphological changes observed for moderately thermal inactivated lysates (15% phage inactivation) of the heat tolerant phage P635.

M3 - Conference abstract for conference

T2 - 9th Symposium on Food Microbiology

Y2 - 12 May 2011 through 13 May 2011

ER -

Heat tolerance of dairy lactococcal c2 phages

Abstract

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