scholarly journals Prediction of a Required Log Reduction with Probability for Enterobacter sakazakii during High-Pressure Processing, Using a Survival/Death Interface Model

2009 ◽  
Vol 75 (7) ◽  
pp. 1885-1891 ◽  
Author(s):  
Shige Koseki ◽  
Maki Matsubara ◽  
Kazutaka Yamamoto
Keyword(s):  
High Pressure ◽  
Processing Condition ◽  
High Pressure Processing ◽  
Inactivation Kinetics ◽  
Enterobacter Sakazakii ◽  
Inoculum Level ◽  
Log Reduction ◽  
Dummy Variable ◽  
Level 3 ◽  
Probability Of Death

ABSTRACT A probabilistic model for predicting Enterobacter sakazakii inactivation in trypticase soy broth (TSB) and infant formula (IF) by high-pressure processing was developed. The modeling procedure is based on a previous model (S. Koseki and K. Yamamoto, Int. J. Food Microbiol. 116:136-143, 2007) that describes the probability of death of bacteria. The model developed in this study consists of a total of 300 combinations of pressure (400, 450, 500, 550, or 600 MPa), pressure-holding time (1, 3, 5, 10, or 20 min), temperature (25 or 40°C), inoculum level (3, 5, or 7 log10 CFU/ml), and medium (TSB or IF), with each combination tested in triplicate. For each replicate response of E. sakazakii, survival and death were scored with values of 0 and 1, respectively. Data were fitted to a logistic regression model in which the medium was treated as a dummy variable. The model predicted that the required pressure-holding times at 500 MPa for a 5-log reduction in IF with 90% achievement probability were 26.3 and 7.9 min at 25 and 40°C, respectively. The probabilities of achieving 5-log reductions in TSB and IF by treatment with 400 MPa at 25°C for 10 min were 92 and 3%, respectively. The model enabled the identification of a minimum processing condition for a required log reduction, regardless of the underlying inactivation kinetics pattern. Simultaneously, the probability of an inactivation effect under the predicted processing condition was also provided by taking into account the environmental factors mentioned above.

Toward Validation of Process Criteria for High-Pressure Processing of Orange Juice with Predictive Models

2005 ◽  
Vol 68 (5) ◽  
pp. 949-954 ◽  
Author(s):  
MICHELLE K. BULL ◽  
ELIZABETH A. SZABO ◽  
MARTIN B. COLE ◽  
CYNTHIA M. STEWART
Keyword(s):  
High Pressure ◽  
Orange Juice ◽  
Fruit Juice ◽  
Control Point ◽  
High Pressure Processing ◽  
Navel Orange ◽  
Inoculum Level ◽  
Log Reduction ◽  
Valencia Orange ◽  
Pressure Magnitude

Mathematical models were developed to predict time to inactivation (TTI) by high-pressure processing of Salmonella in Australian Valencia orange juice (pH 4.3) and navel orange juice (pH 3.7) as a function of pressure magnitude (300 to 600 MPa) and inoculum level (3 to 7 log CFU/ml). For each model, the TTI was found to increase with increasing inoculum level and decrease with increasing pressure magnitude. The U.S. Food and Drug Administration Juice Hazard Analysis and Critical Control Point Regulation requires fruit juice processors to include control measures that produce a 5-log reduction of the pertinent microorganism of public health significance in the juice. To achieve a 5-log reduction of Salmonella in navel orange juice at 20°C, the models predicted hold times of 198, 19, and 5 s at 300, 450, and 600 MPa, respectively. In Valencia orange juice at 20°C, a 5-log reduction of Salmonella was achieved in 369, 25, and 5 s at 300, 450, and 600 MPa, respectively. At pressures below 400 MPa, Salmonella was more sensitive to pressure in the more acidic conditions of the navel orange juice and TTIs were shorter. At higher pressures, little difference in the predicted TTI was observed. Refrigerated storage (4°C) of inoculated navel orange juice treated at selected pressure/time/inoculum combinations showed that under conditions in which viable Salmonella was recovered immediately after high-pressure processing, pressure-treated Salmonella was susceptible to the acidic environment of orange juice or to chill storage temperature. These TTI models can assist fruit juice processors in selecting processing criteria to achieve an appropriate performance criterion with regard to the reduction of Salmonella in orange juice, while allowing for processing flexibility and optimization of high-pressure juice processing.

Effect of High-Pressure Processing on Strains of Enterobacter sakazakii

2006 ◽  
Vol 69 (4) ◽  
pp. 935-937 ◽  
Author(s):  
S. GONZÁLEZ ◽  
G. J. FLICK ◽  
F. M. ARRITT ◽  
D. HOLLIMAN ◽  
B. MEADOWS
Keyword(s):  
High Pressure ◽  
Protective Effect ◽  
Infant Formula ◽  
High Pressure Processing ◽  
The Other ◽  
Powdered Infant Formula ◽  
Enterobacter Sakazakii ◽  
Log Reduction

Four strains of Enterobacter sakazakii were inoculated into tryptic soy broth and reconstituted powdered infant formula and exposed to high-pressure processing. Pressures of 200, 400, and 600 MPa were used for each medium for 1 min. E. sakazakii was reduced by more than 6 log (strains A and B) in both media at 600 MPa. Strain B was significantly (P ≤ 0.05) more pressure resistant than the other strains, with just more than a 3-log reduction at 600 MPa in both media. The reconstituted infant formula has a significant (P ≤ 0.05) protective effect for certain strains and pressures (strain B at 400 MPa and strain D at 400 and 600 MPa). Differences in log reductions between media (milk and broth) were also observed for certain strains and specific pressures (strain B at 400 MPa and strain D at 400 and 600 MPa; P ≤ 0.05). This research showed that E. sakazakii, when present in reconstituted powdered infant formula, can be submitted to high-pressure processing (600 MPa for 1 min) and achieve log reductions ranging from 3 to 6.84, depending on the strain.

Inactivation of Bacterial Pathogens in Human Milk by High-Pressure Processing†

2008 ◽  
Vol 71 (1) ◽  
pp. 109-118 ◽  
Author(s):  
S. VIAZIS ◽  
B. E. FARKAS ◽  
L. A. JAYKUS
Keyword(s):  
High Pressure ◽  
Human Milk ◽  
Capillary Tube ◽  
Bacterial Pathogens ◽  
High Pressure Processing ◽  
Viral Pathogens ◽  
Promising Alternative ◽  
Log Reduction ◽  
Long Time ◽  
Thermal Pasteurization

Low-temperature, long-time (LTLT) pasteurization assures the safety of banked human milk; however, heat can destroy important nutritional biomolecules. High-pressure processing (HPP) shows promise as an alternative for pasteurization of breast milk. The purpose of this study was to investigate the efficacy of HPP for inactivation of selected bacterial pathogens in human milk. Human milk was inoculated with one of five pathogens (108 to 109 CFU/ml), while 0.1% peptone solution solutions with the same levels of each organism were used as controls. The samples were subjected to 400 MPa at 21 to 31°C for 0 to 50 min or to 62.5°C for 0 to 30 min (capillary tube method) to simulate LTLT pasteurization. Tryptic soy agar and selective media were used for enumeration. Traditional thermal pasteurization resulted in inactivation (>7 log) of all pathogens within 10 min. In human milk and in peptone solution, a 6-log reduction was achieved after 30 min of HPP for Staphylococcus aureus ATCC 6538. After 30 min, S. aureus ATCC 25923 was reduced by 8 log and 6 log in human milk and peptone solution, respectively. Treatments of 4 and 7 min resulted in an 8-log inactivation of Streptococcus agalactiae ATCC 12927 in human milk and peptone solution, respectively, while Listeria monocytogenes ATCC 19115 required 2 min for an 8-log inactivation in human milk. Escherichia coli ATCC 25922 was inactivated by 8 log after 10 min in peptone solution and by 6 log after 30 min in human milk. These data suggest that HPP may be a promising alternative for pasteurization of human milk. Further research should evaluate the efficacy of HPP in the inactivation of relevant viral pathogens.

Effect of High Hydrostatic Pressure on Salmonella Inoculated into Creamy Peanut Butter with Modified Composition

2014 ◽  
Vol 77 (10) ◽  
pp. 1664-1668 ◽  
Author(s):  
TANYA D'SOUZA ◽  
MUKUND KARWE ◽  
DONALD W. SCHAFFNER
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Water Activity ◽  
High Hydrostatic Pressure ◽  
Peanut Butter ◽  
High Pressure Processing ◽  
Peanut Oil ◽  
Peanut Flour ◽  
Log Reduction ◽  
High Hydrostatic Pressure Processing

Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.

Inactivation of Yersinia pseudotuberculosis 197 and Francisella tularensis LVS in Beverages by High Pressure Processing

2009 ◽  
Vol 72 (1) ◽  
pp. 165-168 ◽  
Author(s):  
JOSEPH E. SCHLESSER ◽  
BRIAN PARISI
Keyword(s):  
High Pressure ◽  
Francisella Tularensis ◽  
Orange Juice ◽  
Yersinia Pseudotuberculosis ◽  
Hold Time ◽  
Skim Milk ◽  
High Pressure Processing ◽  
Pressure Treatment ◽  
Log Reduction ◽  
Pressure Resistance

In 2003, the U.S. Department of Health and Human Services announced a new research program to develop technologies and strategies to prevent and minimize potential food safety and security threats. The threat of terrorist attacks against the nation's food supplies has created the need to study microorganisms not typically associated with foodborne illness. High-pressure processing has been proposed as a treatment to reduce Yersinia pestis and Francisella tularensis LVS levels in beverages. The objectives of this work were to determine the pressure resistance of Y. pseudotuberculosis 197 (surrogate for Y. pestis) and F. tularensis LVS (vaccine strain). For each bacterium, samples of ultrahigh-temperature pasteurized skim milk and pasteurized reduced-acid orange juice (pH ca. 4.2) were inoculated at a minimum level of 5 log CFU/ml. Ten-milliliter samples of the inoculated product were vacuum sealed in polyester pouches and subjected to pressures of 300 and 500 MPa for holding times ranging from 30 s to 6 min. One set of trials was performed at an initial temperature of 10°C and another at 25°C. Processed samples were immediately plated and enumerated. A pressure treatment of 300 MPa at 25°C for less than 6 min was not sufficient to achieve a 5-log reduction of Y. pseudotuberculosis 197 or F. tularensis LVS in milk. However, a pressure treatment of 500 MPa was effective at hold times as low as 30 s. Overall, F. tularensis LVS demonstrated less pressure resistance than Y. pseudotuberculosis 197. Based on these findings, a high-pressure process designed to inactivate 5 log CFU of Y. pseudotuberculosis 197 per ml and F. tularensis LVS in orange juice or milk should be set at or above 500 MPa with a hold time of 2 min or greater.

scholarly journals Inactivation of a Norovirus by High-Pressure Processing

2006 ◽  
Vol 73 (2) ◽  
pp. 581-585 ◽  
Author(s):  
David H. Kingsley ◽  
Daniel R. Holliman ◽  
Kevin R. Calci ◽  
Haiqiang Chen ◽  
George J. Flick
Keyword(s):  
High Pressure ◽  
Pressure Range ◽  
Room Temperature ◽  
Initial Temperature ◽  
High Pressure Processing ◽  
Inactivation Kinetics ◽  
Virus Inactivation ◽  
Pressure Treatment ◽  
Murine Norovirus ◽  
Human Norovirus

ABSTRACT Murine norovirus (strain MNV-1), a propagable norovirus, was evaluated for susceptibility to high-pressure processing. Experiments with virus stocks in Dulbecco's modified Eagle medium demonstrated that at room temperature (20°C) the virus was inactivated over a pressure range of 350 to 450 MPa, with a 5-min, 450-MPa treatment being sufficient to inactivate 6.85 log10 PFU of MNV-1. The inactivation of MNV-1 was enhanced when pressure was applied at an initial temperature of 5°C; a 5-min pressure treatment of 350 MPa at 30°C inactivated 1.15 log10 PFU of virus, while the same treatment at 5°C resulted in a reduction of 5.56 log10 PFU. Evaluation of virus inactivation as a function of treatment times ranging from 0 to 150 s and 0 to 900 s at 5°C and 20°C, respectively, indicated that a decreasing rate of inactivation with time was consistent with Weibull or log-logistic inactivation kinetics. The inactivation of MNV-1 directly within oyster tissues was demonstrated; a 5-min, 400-MPa treatment at 5°C was sufficient to inactivate 4.05 log10 PFU. This work is the first demonstration that norovirus can be inactivated by high pressure and suggests good prospects for inactivation of nonpropagable human norovirus strains in foods.

scholarly journals Evaluation of High-Pressure Processing in Inactivation of the Hepatitis E Virus

2019 ◽  
Author(s):  
Neda Nasheri ◽  
Tanushka Doctor ◽  
Angela Chen ◽  
Jennifer Harlow ◽  
Alexander Gill
Keyword(s):  
High Pressure ◽  
Hepatitis E Virus ◽  
Foodborne Pathogen ◽  
Hepatitis E ◽  
Developed Countries ◽  
High Pressure Processing ◽  
Pathogen Inactivation ◽  
Genotype 3 ◽  
Similar Treatment ◽  
Log Reduction

Hepatitis E virus (HEV) causes acute hepatitis with approximately 20 million cases per year globally. While HEV is endemic in certain regions of Asia, Africa and South America, it is considered an emerging foodborne pathogen in developed countries. Based on genetic diversity, HEV is classified into different genotypes, with genotype 3 (HEV-3) being most prevalent in Europe and North America. The transmission of HEV-3 has been shown to be zoonotic and mainly associated with the consumption of raw or undercooked pork products. Herein, we investigated the efficacy of high-pressure processing (HPP) in the inactivation of HEV-3 using a cell culture system. HPP has been indicated as a promising nonthermal pathogen inactivation strategy for treatment of certain high-risk food commodities, without any noticeable changes in their nature. For this purpose, we treated HEV-3 in media as well as in artificially inoculated pork pâté, with different conditions of HPP: 400 MPa for 1 and 5 minutes, as well as 600 MPa for 1 and 5 minutes, at ambient temperature. In general, we observed approximately a 2-log reduction in HEV load by HPP treatments in media; however, similar treatment in the pork pâté resulted in a much lower reduction in viral load. Therefore, the efficacy of HPP treatment in the inactivation of HEV-3 is matrix-dependent.

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