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

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.

Foods ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 169 ◽  
Author(s):  
Biniam Kebede ◽  
Pui Lee ◽  
Sze Leong ◽  
Vidya Kethireddy ◽  
Qianli Ma ◽  
...  

High-Pressure Processing (HPP) and Pulsed Electric Fields (PEF) processing technologies are being used increasingly on a commercial basis, with high-quality labelled fruit juices being one of the most important promotion strategies. Quality-related enzymes, which might still be active after HPP and PEF pasteurization, can cause undesirable aroma changes during storage. This study investigated volatile changes during the shelf life of PEF (15.5 kV/cm and specific energy of 158 kJ/L), HPP (600 MPa for 3 min), and thermally (72 °C for 15 s) pasteurized Jazz apple juices—up to five weeks. To have an increased insight into the volatile changes, an integrated instrumental (GC-MS) and data analysis (chemometrics) approach was implemented. Immediately after pasteurization, PEF processing resulted a better retention of odor-active volatiles, such as (E)-2-hexenal and hexyl acetate, whereas thermal processing lowered their amount. During refrigerated storage, these volatiles have gradually decreased in all processed juices. By the end of storage, the amount of these aroma relevant volatiles appears to still be higher in PEF and HPP pasteurized juices compared to their conventional counterparts. This study demonstrated the potential of advanced chemometric approaches to obtain increased insight into complex shelf life changes.


2014 ◽  
Vol 77 (10) ◽  
pp. 1664-1668 ◽  
Author(s):  
TANYA D'SOUZA ◽  
MUKUND KARWE ◽  
DONALD W. SCHAFFNER

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.


2009 ◽  
Vol 72 (1) ◽  
pp. 165-168 ◽  
Author(s):  
JOSEPH E. SCHLESSER ◽  
BRIAN PARISI

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.


2019 ◽  
Author(s):  
Neda Nasheri ◽  
Tanushka Doctor ◽  
Angela Chen ◽  
Jennifer Harlow ◽  
Alexander Gill

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.


Author(s):  
Elise Mank ◽  
Eva Kontopodi ◽  
Annemieke C. Heijboer ◽  
Ruurd M. van Elburg ◽  
Kasper Hettinga ◽  
...  

2020 ◽  
Vol 122 (12) ◽  
pp. 3969-3979 ◽  
Author(s):  
Rodrigo Rodrigues Petrus ◽  
John Joseph Churey ◽  
Randy William Worobo

PurposeHigh-acid liquid foods are a substrate in which foodborne pathogens can maintain their viability. In this research an experimental design was conducted to optimize the parameters for high pressure processing (HPP) of apple juice (pH 3.76).Design/methodology/approachJuice was inoculated with cocktails of Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes. Pressures ranging from 139 to 561 MPa and dwell times between 39 and 181 s were challenged.FindingsPressures above 400 MPa achieved a greater than 5-log reduction in all pathogen cocktails regardless of the dwell time. L. monocytogenes was more sensitive to HPP at a pressure of 350 MPa and dwell times equal to or beyond 110 s. E. coli O157:H7 and S. enterica exhibited similar resistance; the number of log reductions in the central point (350 MPa/110 s) ranged from 2.2 to 3.7. The first-order mathematical model better fitted experimental data for E. coli O157:H7 and S. enterica. In regard to L. monocytogenes, the second-order model better fitted this pathogen's reduction.Practical implicationsFruit juices are usually high pressure processed at approximately 600 MPa. For pathogenic reduction, the use of milder parameters may save energy and maintenance costs. The results herein exhibited could assist the apple juice industry with more effective applications of HPP.Originality/valueThe findings of this study demonstrate that relatively moderate pressures can be successfully used to assure the safety of apple juice.


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