Biphasic Inactivation Kinetics of Escherichia coli in Liquid Whole Egg by High Hydrostatic Pressure Treatments

2001 ◽  
Vol 17 (6) ◽  
pp. 1020-1025 ◽  
Author(s):  
D.-U. Lee ◽  
V. Heinz ◽  
D. Knorr
2009 ◽  
Vol 6 (6) ◽  
pp. 649-656 ◽  
Author(s):  
Maria Consuelo Pina-Pérez ◽  
Angela B. Silva-Angulo ◽  
Begoña Muguerza-Marquínez ◽  
D. Rodrigo Aliaga ◽  
Antonio Martínez López

2008 ◽  
Vol 71 (10) ◽  
pp. 2007-2013 ◽  
Author(s):  
INEKE K. H. VAN BOEIJEN ◽  
ROY MOEZELAAR ◽  
TJAKKO ABEE ◽  
MARCEL H. ZWIETERING

High hydrostatic pressure (HHP) inactivation of three Listeria monocytogenes strains (EGDe, LO28, and Scott A) subjected to 350 MPa at 20°C in ACES buffer resulted in survival curves with significant tailing for all three strains. A biphasic linear model could be fitted to the inactivation data, indicating the presence of an HHP-sensitive and an HHP-resistant fraction, which both showed inactivation according to first-order kinetics. Inactivation parameters of these subpopulations of the three strains were quantified in detail. EGDe showed the highest D-values for the sensitive and resistant fraction, whereas LO28 and Scott A showed lower HHP resistance for both fractions. Survivors isolated from the tail of LO28 and EGDe were analyzed, and it was revealed that the higher resistance of LO28 was a stable feature for 24% (24 of 102) of the resistant fraction. These HHP-resistant variants were 10 to 600,000 times more resistant than wild type when exposed to 350 MPa at 20°C for 20 min. Contrary to these results, no stable HHP-resistant isolates were found for EGDe (0 of 102). The possible effect of HHP survival capacity of stress-resistant genotypic and phenotypic variants of L. monocytogenes on the safety of HHP-processed foods is discussed.


2020 ◽  
Vol 10 (21) ◽  
pp. 7542
Author(s):  
Patra Sourri ◽  
Anthoula A. Argyri ◽  
Efstathios Z. Panagou ◽  
George-John E. Nychas ◽  
Chrysoula C. Tassou

In this work, the inactivation kinetics of Alicyclobacillus acidoterrestris spores by temperature-assisted high hydrostatic pressure was assessed by means of the Weibull model. Spores from two A. acidoterrestris strains (a wild-type strain and a reference strain) were inoculated in commercial orange juice and subjected to high pressure levels (500 and 600 MPa) combined with four temperature regimes (25, 45, 60 and 70 °C) for time up to 30 min. Results showed that for a given high-pressure level spore inactivation was higher as temperature progressively increased. Furthermore, the Weibull model consistently produced satisfactory fit to the inactivation data based on the values of the root mean squared error (RMSE < 0.54 log colony-forming units (CFU)/mL) and the coefficient of determination (R2 > 0.90 in most cases). The shape of inactivation curves was concave upward (p < 1) for all temperature/high pressure levels tested, indicating rapid inactivation of the sensitive cells of the bacterium whereas the remaining ones adapted to high hydrostatic pressure (HHP) treatment. The values of the shape (p) and scale (δ) parameters of the Weibull model were dependent on the applied temperature for a given high pressure level and they were further described in a secondary model using first-order fitting curves to provide predictions of the surviving spore population at 55 and 65 °C. Results revealed a systematic over-prediction for the wild-type strain regardless of temperature and high pressure applied, whereas for the reference strain under-prediction was evident after 3 log-cycles reduction of the surviving bacteria spores. Overall, the results obtained indicate that the effectiveness of high hydrostatic pressure against A. acidoterrestris spores is strain-dependent and also underline the need for temperature-assisted HPP for effective spore inactivation during orange juice processing.


2012 ◽  
Vol 14 ◽  
pp. 1-10 ◽  
Author(s):  
Silvia Monfort ◽  
Sergio Ramos ◽  
Nicolás Meneses ◽  
Dietrich Knorr ◽  
Javier Raso ◽  
...  

2016 ◽  
Vol 5 (1-2) ◽  
pp. 148-152
Author(s):  
Adrienn Tóth ◽  
Csaba Németh ◽  
Réka Juhász ◽  
Ildikó Zeke ◽  
Salamon Bertold ◽  
...  

Samples prepared from liquid egg yolk (LEY), liquid egg white (LEW) and liquid whole egg (LWE) were processed by high hydrostatic pressure (HHP) using different holding times (60, 180, 300, 420 and 600 s). The aim of our experiment was to examine how different holding times influences technofunctional attributes of liquid egg products. The color of samples changed after 60 s HHP treatment, but visible changes were evaluated just after 180­ 300 s. The pH of samples was stable, there were no significant changes caused by HHP (one-way ANOVA, a=0,05). The apparent viscosity was measured by a rotational viscometer as a function of shear rate. The shearthinning behavior of LEY and pseudopastic behavior of LEW and LWE were fitted well into HerschelBulkley model (with a satisfying correlation of R2 > 0.96). For the selected shearing rate, viscosity was measured in relation to shearing time. Thixotropic behavior of samples was increased by longer holding time of HHP treatments.


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