Characterization and substrate-accelerated thermal inactivation kinetics of a new serine-type arylsulfatase

Produce has been associated with a rising number of foodborne illness outbreaks. While much produce is consumed raw, some is treated with mild heat, such as blanching or cooking. The objectives of this research were to compare the thermal inactivation kinetics of Listeria monocytogenes, Salmonella enterica, Shiga toxin–producing Escherichia coli (STEC) O157:H7, and non-O157 STEC in phosphate-buffered saline (PBS; pH 7.2) and a spinach homogenate and to provide an estimate of the safety of mild heat processes for spinach. Five individual strains of S. enterica, L. monocytogenes, STEC O157:H7, and non-O157 STEC were tested in PBS in 2-ml glass vials, and cocktails of the organisms were tested in blended spinach in vacuum-sealed bags. For Listeria and Salmonella at 56 to 60°C, D-values in PBS ranged from 4.42 ± 0.94 to 0.35 ± 0.03 min and 2.11 ± 0.14 to 0.16 ± 0.03 min, respectively. D-values at 54 to 58°C were 5.18 ± 0.21 to 0.53 ± 0.04 min for STEC O157:H7 and 5.01 ± 0.60 to 0.60 ± 0.13 min for non-O157 STEC. In spinach at 56 to 60°C, Listeria D-values were 11.77 ± 2.18 to 1.22 ± 0.12 min and Salmonella D-values were 3.51 ± 0.06 to 0.47 ± 0.06 min. D-values for STEC O157:H7 and non-O157 STEC were 7.21 ± 0.17 to 1.07 ± 0.11 min and 5.57 ± 0.38 to 0.99 ± 0.07 min, respectively, at 56 to 60°C. In spinach, z-values were 4.07 ± 0.16, 4.59 ± 0.26, 4.80 ± 0.92, and 5.22 ± 0.20°C for Listeria, Salmonella, STEC O157:H7, and non-O157 STEC, respectively. Results indicated that a mild thermal treatment of blended spinach at 70°C for less than 1 min would result in a 6-log reduction of all pathogens tested. These findings may assist the food industry in the design of suitable mild thermal processes to ensure food safety.

Download Full-text

THERMAL INACTIVATION KINETICS of TRYPSIN AT ASEPTIC PROCESSING TEMPERATURES

Journal of Food Process Engineering ◽

10.1111/j.1745-4530.1993.tb00324.x ◽

1993 ◽

Vol 16 (4) ◽

pp. 315-328 ◽

Cited By ~ 18

Author(s):

G.B. AWUAH ◽

H.S. RAMASWAMY ◽

B.K. SIMPSON ◽

J.P. SMITH

Keyword(s):

Thermal Inactivation ◽

Inactivation Kinetics ◽

Aseptic Processing ◽

Kinetics Of

Download Full-text

Thermal Inactivation Kinetics of Sporolactobacillus nakayamae Spores, a Spoilage Bacterium Isolated from a Model Mashed Potato–Scallion Mixture

Journal of Food Protection ◽

10.4315/0362-028x.jfp-16-103 ◽

2016 ◽

Vol 79 (9) ◽

pp. 1482-1489

Author(s):

HAYRIYE BOZKURT ◽

JAIRUS R. D. DAVID ◽

RYAN J. TALLEY ◽

D. SCOTT LINEBACK ◽

P. MICHAEL DAVIDSON

Keyword(s):

Heat Resistance ◽

Thermal Inactivation ◽

Weibull Model ◽

Inactivation Kinetics ◽

Order Model ◽

First Order ◽

Different Temperatures ◽

Spoilage Bacterium ◽

D Values ◽

Kinetics Of

ABSTRACT Sporolactobacillus species have been occasionally isolated from spoiled foods and environmental sources. Thus, food processors should be aware of their potential presence and characteristics. In this study, the heat resistance and influence of the growth and recovery media on apparent heat resistance of Sporolactobacillus nakayamae spores were studied and described mathematically. For each medium, survivor curves and thermal death curves were generated for different treatment times (0 to 25 min) at different temperatures (70, 75, and 80°C) and Weibull and first-order models were compared. Thermal inactivation data for S. nakayamae spores varied widely depending on the media formulations used, with glucose yeast peptone consistently yielding the highest D-values for the three temperatures tested. For this same medium, the D-values ranged from 25.24 ± 1.57 to 3.45 ± 0.27 min for the first-order model and from 24.18 ± 0.62 to 3.50 ± 0.24 min for the Weibull model at 70 and 80°C, respectively. The z-values determined for S. nakayamae spores were 11.91 ± 0.29°C for the Weibull model and 11.58 ± 0.43°C for the first-order model. The calculated activation energy was 200.5 ± 7.3 kJ/mol for the first-order model and 192.8 ± 22.1 kJ/mol for the Weibull model. The Weibull model consistently produced the best fit for all the survival curves. This study provides novel and precise information on thermal inactivation kinetics of S. nakayamae spores that will enable reliable thermal process calculations for eliminating this spoilage bacterium.

Download Full-text

Thermal inactivation kinetics of peroxidase and polyphenol oxidase from pomegranate arils ( Punica granatum L. cv. Wonderful)

Journal of Food Biochemistry ◽

10.1111/jfbc.13428 ◽

2020 ◽

Vol 44 (10) ◽

Author(s):

Ahmed Rayan ◽

Noha Morsy

Keyword(s):

Polyphenol Oxidase ◽

Thermal Inactivation ◽

Punica Granatum ◽

Inactivation Kinetics ◽

Kinetics Of ◽

Punica Granatum L ◽

Pomegranate Arils

Download Full-text

Thermal Inactivation Kinetics of Human Norovirus Surrogates and Hepatitis A Virus in Turkey Deli Meat

Applied and Environmental Microbiology ◽

10.1128/aem.00874-15 ◽

2015 ◽

Vol 81 (14) ◽

pp. 4850-4859 ◽

Cited By ~ 10

Author(s):

Hayriye Bozkurt ◽

Doris H. D'Souza ◽

P. Michael Davidson

Keyword(s):

Hepatitis A ◽

Thermal Inactivation ◽

Hepatitis A Virus ◽

Weibull Model ◽

Activation Energies ◽

Inactivation Kinetics ◽

Order Model ◽

Decimal Reduction Time ◽

First Order ◽

Kinetics Of

ABSTRACTHuman noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to the consumption of presliced ready-to-eat deli meats. The objectives of this research were to determine the thermal inactivation kinetics of HNoV surrogates (murine norovirus 1 [MNV-1] and feline calicivirus strain F9 [FCV-F9]) and HAV in turkey deli meat, compare first-order and Weibull models to describe the data, and calculate Arrhenius activation energy values for each model. TheD(decimal reduction time) values in the temperature range of 50 to 72°C calculated from the first-order model were 0.1 ± 0.0 to 9.9 ± 3.9 min for FCV-F9, 0.2 ± 0.0 to 21.0 ± 0.8 min for MNV-1, and 1.0 ± 0.1 to 42.0 ± 5.6 min for HAV. Using the Weibull model, thetD = 1(time to destroy 1 log) values for FCV-F9, MNV-1, and HAV at the same temperatures ranged from 0.1 ± 0.0 to 11.9 ± 5.1 min, from 0.3 ± 0.1 to 17.8 ± 1.8 min, and from 0.6 ± 0.3 to 25.9 ± 3.7 min, respectively. Thez(thermal resistance) values for FCV-F9, MNV-1, and HAV were 11.3 ± 2.1°C, 11.0 ± 1.6°C, and 13.4 ± 2.6°C, respectively, using the Weibull model. Thezvalues using the first-order model were 11.9 ± 1.0°C, 10.9 ± 1.3°C, and 12.8 ± 1.7°C for FCV-F9, MNV-1, and HAV, respectively. For the Weibull model, estimated activation energies for FCV-F9, MNV-1, and HAV were 214 ± 28, 242 ± 36, and 154 ± 19 kJ/mole, respectively, while the calculated activation energies for the first-order model were 181 ± 16, 196 ± 5, and 167 ± 9 kJ/mole, respectively. Precise information on the thermal inactivation of HNoV surrogates and HAV in turkey deli meat was generated. This provided calculations of parameters for more-reliable thermal processes to inactivate viruses in contaminated presliced ready-to-eat deli meats and thus to reduce the risk of foodborne illness outbreaks.

Download Full-text