Inhibitory effect of high hydrostatic pressure, nisin, and moderate heating on the inactivation of Paenibacillus sp. and Terribacillus aidingensis spores isolated from UHT milk

The combined effects of high hydrostatic pressure and heat on the inactivation of Escherichia coli O157:H7 NCTC 12079 and Staphylococcus aureus NCTC 10652 in poultry meat and ultra-high-temperature-treated (UHT) milk were investigated. The simultaneous application of high pressure and mild heating was more lethal than either treatment alone. The substrate was found to have a significant effect on the survival of the pathogens during treatment. For E. coli O157:H7, a 15-min treatment of 400 MPa at 50°C resulted in approximately a 6.0-log10 reduction in CFU/g in poultry meat and a 5.0-log10 reduction in UHT milk; however, a < 1-log10 reduction was achieved with either treatment alone. In contrast, for S. aureus, a 15-min treatment of 500 MPa at 50°C was required to achieve a 5.0-log10 reduction in poultry meat and a 6.0-log10 reduction in UHT milk. As before, a <1-log10 reduction in numbers was achieved with either treatment alone. The pressure-temperature inactivation curves of each organism, in each substrate, were fitted using the Gompertz equation. Polynomial expressions derived from the Gompertz variables were used to devise simple models which predicted the inactivation of each pathogen at various pressure-temperature combinations. Thus, a number of different pressure-temperature conditions could be chosen to achieve a desired inactivation level. The use of such models will provide flexibility in selecting optimum pressure processing conditions without compromising microbiological safety.

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Effects of Different Nitrite Concentrations from a Vegetable Source with and without High Hydrostatic Pressure on the Recovery of Listeria monocytogenes on Ready-to-Eat Restructured Ham

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-401 ◽

2014 ◽

Vol 77 (5) ◽

pp. 781-787 ◽

Cited By ~ 1

Author(s):

NICOLAS A. LAVIERI ◽

JOSEPH G. SEBRANEK ◽

JOSEPH C. CORDRAY ◽

JAMES S. DICKSON ◽

ASHLEY M. HORSCH ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Storage Period ◽

Inhibitory Effect ◽

Inhibitory Effects ◽

Sampling Protocols ◽

Layer Medium ◽

Agar Layer ◽

Synergistic Inhibitory Effect

Sodium nitrite exerts an inhibitory effect on the growth of Listeria monocytogenes. The objective of this study was to investigate the effects of various nitrite concentrations from a vegetable source with and without high hydrostatic pressure (HHP) on the recovery and growth of L. monocytogenes on ready-to-eat restructured ham. A preconverted celery powder was used as the vegetable source of nitrite. Targeted concentrations of natural nitrite investigated were 0, 50, and 100 mg/kg. HHP treatments evaluated were 400 MPa for 4 min and 600 MPa for 1 or 4 min at 12 ± 2°C (initial temperature of the pressurization fluid). Viable L. monocytogenes populations were monitored on modified Oxford medium and thin agar layer medium through 98 days of storage at 4 ± 1°C. Populations on both media did not differ. The HHP treatment at 600 MPa for 4 min resulted in L. monocytogenes populations below the detection limit of our sampling protocols throughout the storage period regardless of the natural nitrite concentration. The combination of HHP at 400 MPa for 4 min or 600 MPa for 1 min with natural nitrite resulted in initial inhibition of viable L. monocytogenes. Ham formulations that did not contain natural nitrite allowed faster growth of L. monocytogenes than did those with nitrite, regardless of whether they were treated with HHP. The results indicate that nitrite from a vegetable source at the concentrations used in this study resulted in slower growth of this microorganism. HHP treatments enhanced the inhibitory effects of natural nitrite on L. monocytogenes growth. Thus, the combination of natural nitrite plus HHP appears to have a synergistic inhibitory effect on L. monocytogenes growth.

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Impact of High Hydrostatic Pressure Treatment on Microbial Communities in Chinese Water-Boiled Salted Duck

Journal of Food Protection ◽

10.4315/0362-028x.jfp-13-386 ◽

2014 ◽

Vol 77 (7) ◽

pp. 1142-1147 ◽

Cited By ~ 2

Author(s):

YULIN FENG ◽

KEPING YE ◽

HUHU WANG ◽

YI SUN ◽

XINGLIAN XU ◽

...

Keyword(s):

Hydrostatic Pressure ◽

Shelf Life ◽

Microbial Communities ◽

High Hydrostatic Pressure ◽

Denaturing Gradient Gel Electrophoresis ◽

Inhibitory Effect ◽

Mild Heat ◽

Chinese Water ◽

Gradient Gel Electrophoresis ◽

The Impact

The objective of this study was to determine the impact of high hydrostatic pressure (HHP) treatment on microbial communities in Chinese water-boiled salted duck (CWBSD) and the synergistic effect of HHP and mild heat treatment. In this work, the bacterial diversity was evaluated by using both a culture-dependent method and denaturing gradient gel electrophoresis. The total aerobic bacterial counts in pressure-treated samples were significantly lower than those in controls, which indicated that HHP could extend the shelf life of CWBSD. Weissella hellenica and Enterobacteriaceae, the predominant bacteria found in CWBSD, were not detected after HHP treatment. On the other hand, Staphylococcus spp. and Bacillus spp. became the predominant bacteria in HHP-treated samples. Moreover, the inhibitory effect was greater at 400 MPa than at 200 MPa combined with mild heat at 40°C. This study investigated the diversity of bacteria in HHP-treated CWBSD, and the information derived from this research may help to understand the bacterial ecology and develop effective HHP treatments to extend the shelf life of CWBSD.

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Comparison of Synergistic Effect of Nisin and Monolaurin on the Inactivation of Three Heat Resistant Spores Studied by Design of Experiments in Milk

Journal of Food Quality ◽

10.1155/2021/9977646 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Souhir Kmiha ◽

Chedia Aouadhi ◽

Khouloud Aziza ◽

Awatef Bejaoui ◽

Abderrazak Maaroufi

Keyword(s):

Synergistic Effect ◽

Dairy Industry ◽

Inhibitory Effect ◽

Combined Effect ◽

Bacterial Spores ◽

Optimum Process ◽

Uht Milk ◽

Heat Resistant ◽

Paenibacillus Sp ◽

Bacillus Spores

Spore forming bacteria are special problems for the dairy industry. Heat treatments are insufficient to kill the spores. This is a continuously increasing problem for the industry, but we should be able to control it. In this context, we investigated the combined effect of nisin, monolaurin, and pH values on three heat resistant spores in UHT milk and distilled water and to select an optimal combination for the maximum spore inactivation. The inhibitory effect of nisin (between 50 and 200 IU/ml), monolaurin (ranging from 150 to 300 µg/ml), and pH (between 5 and 8) was investigated using a central composite plan. Results were analyzed using the response surface methodology (RSM). The obtained data showed that the inactivation of Bacillus spores by the combined effect of nisin-monolaurin varies with spore species, acidity, and nature of the medium in which the bacterial spores are suspended. In fact, Terribacillus aidingensis spores were more resistant, to this treatment, than Paenibacillus sp. and Bacillus sporothermodurans ones. The optimum process parameters for a maximum reduction of bacterial spores (∼3log) were obtained at a concentration of nisin >150 IU/ml and of monolaurin >200 µg/ml. The current study highlighted the presence of a synergistic effect between nisin and monolaurin against heat bacterial spores. So, such treatment could be applied by the dairy industry to decontaminate UHT milk and other dairy products from bacterial spores.

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Sensitivity of Vegetative Pathogens to High Hydrostatic Pressure Treatment in Phosphate-Buffered Saline and Foods

Journal of Food Protection ◽

10.4315/0362-028x-58.5.524 ◽

1995 ◽

Vol 58 (5) ◽

pp. 524-529 ◽

Cited By ~ 339

Author(s):

MARGARET F. PATTERSON ◽

MICHELE QUINN ◽

RYAN SIMPSON ◽

ARTHUR GILMOUR

Keyword(s):

Hydrostatic Pressure ◽

High Hydrostatic Pressure ◽

Salmonella Enteritidis ◽

Poultry Meat ◽

Pressure Sensitivity ◽

Similar Reduction ◽

E Coli ◽

Uht Milk ◽

Different Strains ◽

Phosphate Buffered Saline

The effect of high hydrostatic pressure (up to 700 MPa) at 20°C on the survival of vegetative pathogens was investigated in 10 mM phosphate buffer (pH 7.0), ultra high-temperature-treated (UHT) milk, and poultry meat. In buffer, Yersinia enterocolitica was most sensitive, with a pressure of 275 MPa for 15 min resulting in more than a 105 reduction in numbers of cells. Treatments of 350 MPa, 375 MPa, 450 MPa, 700 MPa, and 700 MPa for 15 min were needed to achieve a similar reduction in Salmonella typhimurium, Listeria monocytogenes, Salmonella enteritidis, Escherichia coli O157:H7, and Staphylococcus aureus respectively. A significant variation in pressure sensitivity was observed between different strains of both L monocytogenes and E. coli O157:H7. The most resistant strains (L. monocytogenes NCTC 11994 and E. coli O157:H7 NCTC 12079) were chosen for further studies on the effect of substrate on pressure sensitivity. In both cases the organisms were more resistant to pressure when treated in UHT milk than in poultry meat or buffer. There was evidence, assessed by differential plating using trypticase soy agar with and without additional NaCl, that sublethally injured cells were present at pressures lower than were required for death. This information may be of value if pressure is combined with preservation treatments such as mild heating. The variation in results obtained with different organisms and in different substrates should be recognized when recommendations for the pressure processing of foods are being considered.

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Survival of mouse blastocysts after low-temperature preservation under high pressure

Acta Veterinaria Hungarica ◽

10.1556/avet.52.2004.4.10 ◽

2004 ◽

Vol 52 (4) ◽

pp. 479-487 ◽

Cited By ~ 7

Author(s):

Cs. Pribenszky ◽

M. Molnár ◽

S. Cseh ◽

L. Solti

Keyword(s):

Phase Transition ◽

Hydrostatic Pressure ◽

Low Temperature ◽

High Hydrostatic Pressure ◽

Room Temperature ◽

Freezing Point ◽

Significant Loss ◽

Embryo Cryopreservation ◽

Subzero Temperatures ◽

Survival Capacity

Cryoinjuries are almost inevitable during the freezing of embryos. The present study examines the possibility of using high hydrostatic pressure to reduce substantially the freezing point of the embryo-holding solution, in order to preserve embryos at subzero temperatures, thus avoiding all the disadvantages of freezing. The pressure of 210 MPa lowers the phase transition temperature of water to -21°C. According to the results of this study, embryos can survive in high hydrostatic pressure environment at room temperature; the time embryos spend under pressure without significant loss in their survival could be lengthened by gradual decompression. Pressurisation at 0°C significantly reduced the survival capacity of the embryos; gradual decompression had no beneficial effect on survival at that stage. Based on the findings, the use of the phenomena is not applicable in this form, since pressure and low temperature together proved to be lethal to the embryos in these experiments. The application of hydrostatic pressure in embryo cryopreservation requires more detailed research, although the experience gained in this study can be applied usefully in different circumstances.

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