Inactivation of Listeria innocua Inoculated in Liquid Whole Egg by High Hydrostatic Pressure

1998 ◽  
Vol 61 (1) ◽  
pp. 119-122 ◽  
Author(s):  
E. PONCE ◽  
R. PLA ◽  
M. MOR-MUR ◽  
R. GERVILLA ◽  
B. GUAMIS
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Prolonged Exposure ◽  
Microbial Inactivation ◽  
Listeria Innocua ◽  
Decimal Reduction Time ◽  
First Order Kinetics ◽  
Liquid Whole Egg ◽  
D Values ◽  
Whole Egg

The resistance of Listeria innocua, as a model microorganism for Listeria monocytogenes, to high hydrostatic pressure in liquid whole egg was studied at several pressures (300, 350, 400, and 450 MPa), temperatures (−15, 2, and 20°C), and times (5, 10, and 15 min). Listeria innocua was added to liquid whole egg at approximately 106 CFU/ml. Listeria innocua was not totally inactivated in any of the treatments. In general, reduction was better at 2°C than at room temperature, but the greatest inactivation was obtained at 450 MPa at 20°C for 15 min (over 5 log of reduction). The results indicate that microbial inactivation was increased with prolonged exposure to pressure. D values for Listeria innocua were obtained at 400 MPa for two temperatures (2 and 20°C), and different times (0 to 20 min). The microbial inactivation followed apparent first-order kinetics, exhibiting a decimal reduction time of 7.35 min at 2°C and 8.23 min at 20°C.

Thermal Resistance of Aeromonas hydrophila in Liquid Whole Egg†

1997 ◽  
Vol 60 (3) ◽  
pp. 231-236 ◽  
Author(s):  
JAMES D. SCHUMAN ◽  
BRIAN W. SHELDON ◽  
PEGGY M. FOEGEDING
Keyword(s):  
Thermal Resistance ◽  
Aeromonas Hydrophila ◽  
Animal Origin ◽  
Inactivation Kinetics ◽  
Processing Plant ◽  
Decimal Reduction Time ◽  
Heat Resistant ◽  
Liquid Whole Egg ◽  
D Values ◽  
Whole Egg

Aeromonas hydrophila (AH) is a psychrotrophic spoilage bacterium and potential pathogen which has been isolated from a variety of refrigerated foods of animal origin, including raw milk, red meat, poultry, and commercially broken raw liquid whole egg (LWE). Decimal reduction times (D values) of 4 strains of AH (1 egg isolate, 2 egg processing plant isolates, 1 ATCC type strain) were determined in LWE using an immersed sealed capillary tube (ISCT) procedure. Initial populations (7.0 to 8.3 log CFU/tube in 0.05 ml LWE) were heated at 48, 51, 54, 57, and 60°C, and survivors were plated onto starch ampicillin agar (48 h at 28°C). D values ranged from 3.62 to 9.43 min (at 48°C) to 0.026 to 0.040 min (at 60°C). Both processing plant isolates were more heat resistant than the ATCC strain. Decimal reduction time curves (r2 ≤ 0.98) yielded ZD values of 5.02 to 5.59°C, similar to those for other non-spore-forming bacteria. D values of the most heat resistant AH strain were also determined in LWE at 48, 51, and 54°C using a conventional capped test tube procedure (10 ml/tube). Cells heated in test tubes yielded nonlinear (tailing) survivor curves and larger (P ≤ 0.05) apparent D values at each temperature than those obtained using the ISCT method. This study provides the first thermal resistance data for AH in LWE and the first evidence that straight-line semilogarithmic thermal inactivation kinetics may be demonstrated for Aeromonas using the ISCT procedure.

Inactivation Kinetics of Three Listeria monocytogenes Strains under High Hydrostatic Pressure

2008 ◽  
Vol 71 (10) ◽  
pp. 2007-2013 ◽  
Author(s):  
INEKE K. H. VAN BOEIJEN ◽  
ROY MOEZELAAR ◽  
TJAKKO ABEE ◽  
MARCEL H. ZWIETERING
Keyword(s):  
Listeria Monocytogenes ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Inactivation Kinetics ◽  
Wild Type ◽  
First Order Kinetics ◽  
Survival Capacity ◽  
D Values ◽  
Kinetics Of ◽  
Stable Feature

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.

Design and evaluation of a high hydrostatic pressure combined process for pasteurization of liquid whole egg

2012 ◽  
Vol 14 ◽  
pp. 1-10 ◽  
Author(s):  
Silvia Monfort ◽  
Sergio Ramos ◽  
Nicolás Meneses ◽  
Dietrich Knorr ◽  
Javier Raso ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Combined Process ◽  
Liquid Whole Egg ◽  
Whole Egg

Effect of High Hydrostatic Pressure on Listeria innocua 910 CECT Inoculated into Ewe's Milk

1997 ◽  
Vol 60 (1) ◽  
pp. 33-37 ◽  
Author(s):  
R. GERVILLA ◽  
M. CAPELLAS ◽  
V. FERRAGUT ◽  
B. GUAMIS
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Listeria Innocua ◽  
Plate Count ◽  
First Order ◽  
Plate Count Agar ◽  
Selective Agar ◽  
Ewe's Milk ◽  
D Values ◽  
Kinetics Of

Ewe's milk standardized to 6% fat was inoculated with Listeria innocua 910 CECT at a concentration of 107 CFU/ml and treated by high hydrostatic pressure. Treatments consisted of combinations of pressure (200, 300, 350, 400, 450, and 500 MPa), temperature (2, 10, 25, and 50°C), and time (5, 10, and 15 min). To determine numbers of L innocua, listeria selective agar base with listeria selective supplement and plate count agar was used. Low-temperature(2°C) pressurizations produced higher L innocua inactivation than treatments at room temperatures (25°C). Pressures between 450 and 500 MPa for 10 to 15 min were needed to achieve reductions of 7 to 8 log units. The kinetics of destruction of L innocua were first order with D-values of 3.12 min at 2°C and 400 MPa and 4 min at 25°C and 400 MPa. A baroprotective effect of ewe's milk (6% fat) on L innocua was observed in comparison with other studies using different media and similar pressurization conditions.

scholarly journals Effect of high hydrostatic pressure at 400 MPa on quality attributes of liquid egg products

2016 ◽  
Vol 5 (1-2) ◽  
pp. 148-152
Author(s):  
Adrienn Tóth ◽  
Csaba Németh ◽  
Réka Juhász ◽  
Ildikó Zeke ◽  
Salamon Bertold ◽  
...  
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Egg Yolk ◽  
Rotational Viscometer ◽  
Egg Products ◽  
Thixotropic Behavior ◽  
Liquid Whole Egg ◽  
Whole Egg ◽  
One Way Anova ◽  
Shearthinning Behavior

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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