scholarly journals Synergistic Effects of Nisin, Lysozyme, Lactic Acid, and CitricidalTM for Enhancing Pressure-Based Inactivation of Bacillus amyloliquefaciens, Geobacillus stearothermophilus, and Bacillus atrophaeus Endospores

2021 ◽  
Vol 9 (3) ◽  
pp. 653
Author(s):  
Sadiye Aras ◽  
Niamul Kabir ◽  
Sabrina Wadood ◽  
Jyothi George ◽  
Shahid Chowdhury ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Hydrostatic Pressure ◽  
Bacillus Amyloliquefaciens ◽  
Synergistic Effects ◽  
High Pressure Processing ◽  
Geobacillus Stearothermophilus ◽  
Bacillus Atrophaeus ◽  
Elevated Hydrostatic Pressure ◽  
Bacterial Endospores ◽  
Added Benefit

The inactivation of bacterial endospores continues to be the main curtailment for further adoption of high-pressure processing in intrastate, interstate, and global food commerce. The current study investigated the effects of elevated hydrostatic pressure for the inactivation of endospore suspension of three indicator spore-forming bacteria of concern to the food industry. Additionally, the effects of four bacteriocin/bactericidal compounds were studied for augmenting the decontamination efficacy of the treatment. Elevated hydrostatic pressure at 650 MPa and at 50 °C was applied for 0 min (untreated control) and for 3, 7, and 11 min with and without 50K IU of nisin, 224 mg/L lysozyme, 1% lactic acid, and 1% CitricidalTM. The results were statistically analyzed using Tukey- and Dunnett’s-adjusted ANOVA. Under the condition of our experiments, we observed that a well-designed pressure treatment synergized with mild heat and bacteriocin/bactericidal compounds could reduce up to >4 logs CFU/mL (i.e., >99.99%) of bacterial endospores. Additions of nisin and lysozyme were able, to a great extent, to augment (p < 0.05) the decontamination efficacy of pressure-based treatments against Bacillus amyloliquefaciens and Bacillus atrophaeus, while exhibiting no added benefit (p ≥ 0.05) for reducing endospores of Geobacillus stearothermophilus. The addition of lactic acid, however, was efficacious for augmenting the pressure-based reduction of bacterial endospores of the three microorganisms.

scholarly journals Sensitivity of wild-type and rifampicin-resistant O157 and non-O157 Shiga toxin-producing Escherichia coli to elevated hydrostatic pressure and lactic acid in ground meat and meat homogenate

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246735
Author(s):  
Abimbola Allison ◽  
Aliyar Cyrus Fouladkhah
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Hydrostatic Pressure ◽  
Shiga Toxin ◽  
Meat Products ◽  
The United States ◽  
Health Concern ◽  
Ground Meat ◽  
Wild Type ◽  
Elevated Hydrostatic Pressure

Various serogroups of Shiga toxin-producing Escherichia coli have been epidemiologically associated with foodborne disease episodes in the United States and around the globe, with E. coli O157: H7 as the dominant serogroup of public health concern. Serogroups other than O157 are currently associated with about 60% of Shiga toxin-producing E. coli related foodborne illness episodes. Current study evaluated sensitivity of the O157 and epidemiologically important non-O157 serogroups of the pathogen to elevated hydrostatic pressure and 1% lactic acid. Pressure intensity of 250 to 650 MPa were applied for 0 to 7 min for inactivation of strain mixtures of wild-type and rifampicin-resistant E. coli O157, as well as O26, O45, O103, O111, O121, and O145 serogroups and ATCC® 43895™ strain in ground meat and 10% meat homogenate. E. coli O157 were reduced (p < 0.05) from 6.86 ± 0.2 to 4.56 ± 0.1 log CFU/g when exposed to pressure of 650 MPa for 7 min. Corresponding reductions (p < 0.05) for non-O157 E. coli were from 6.98 ± 0.3 to 4.72 ± 0.1. The D-values at 650 MPa were 3.71 and 3.47 min for O157 and non-O157 serogroups, respectively. Presence of 1% lactic acid to a great extent augmented (p < 0.05) decontamination efficacy of the treatment in meat homogenate resulting in up to 5.6 and 6.0 log CFU/mL reductions for O157 and non-O157 serogroups, respectively. Among the tested serogroups, the wild-type and rifampicin-resistant phenotypes exhibited (p ≥ 0.05) comparable pressure sensitivity. Thus, these two phenotypes could be used interchangeably in validation studies. Our results also illustrate that, application of elevated hydrostatic pressure could be utilized for assuring safety of ground and non-intact meat products against various serogroups of Shiga toxin-producing E. coli. Addition of 1% lactic acid additionally provided industrially appreciable augmentation in efficacy of the pressure-based treatments.

Characteristics, Protection and Functional Design of Three-Layer Laminate for Medical Footwear

Tekstilec ◽  
2020 ◽  
Vol 63 (4) ◽  
pp. 256-262
Author(s):  
Beti Rogina-Car ◽  
◽  
Stana Kovačević ◽  
Irena Šabarić ◽  
◽  
...  
Keyword(s):  
Working Conditions ◽  
Protective Clothing ◽  
Barrier Properties ◽  
Functional Design ◽  
Geobacillus Stearothermophilus ◽  
Bacillus Atrophaeus ◽  
Bacterial Endospores ◽  
Sterilization Process

The aim of this paper is to determine the influence of the washing and sterilization process in real hospital conditions on the microbial barrier properties of textile laminate used in medicine for protective clothing. The paper focuses on the functional design of three-layer laminate for medical footwear in surgery and in rooms where aseptic working conditions are required. The permeability and durability of the microbial barrier were determined after 0, 10 and 20 washing and sterilization procedures according to previously developed meth¬ods. Bacterial endospores of apathogenic species of the genera Geobacillus stearothermophilus and Bacillus atrophaeus were used. A functional design of the protective shoe cover was proposed. The results showed an extremely effective microbial barrier and the durability of the sample after 0, 10 and 20 washing and sterilization procedures, and over a period of one, two and three months.

scholarly journals Influence of Washing and Sterilization on Properties of Polyurethane Coated Fabrics Used in Surgery and for Wrapping Sterile Items

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 642
Author(s):  
Beti Rogina-Car ◽  
Stana Kovačević ◽  
Suzana Đorđević ◽  
Dragan Đorđević
Keyword(s):  
Mechanical Damage ◽  
Physical And Mechanical Properties ◽  
Ftir Analysis ◽  
Geobacillus Stearothermophilus ◽  
Bacillus Atrophaeus ◽  
Genus Bacillus ◽  
Medical Textiles ◽  
Bacterial Endospores ◽  
Sterilization Process ◽  
Coated Fabrics

The objective of this work was to determine the influence of washing and sterilization under real hospital conditions on properties of microbial barrier offered by polyurethane coated fabrics used in surgery and for wrapping sterile items. Emphasis was put on the change of surface polyurethane coating by using FTIR analysis. The permeability and durability of the microbial barrier were determined after 0, 10, and 20 washing and sterilization procedures according to previously developed methods. Bacterial endospores of the apathogenic species of the genus Bacillus Geobacillus stearothermophilus and Bacillus atrophaeus were used. Mechanical damage to medical textiles in the washing and sterilization process was determined according to standard HRN EN ISO 13914-1:2008 and associated with changes in physical and mechanical properties. Chemical changes of PU coatings were determined using FTIR analysis. The results showed an exceptionally efficient microbial barrier and its durability in all samples after 0, 10 and 20 washing and sterilization procedures and for a period of one, two and three months.

EFFECT OF HIGH HYDROSTATIC PRESSURE ON SPORES OF GEOBACILLUS STEAROTHERMOPHILUS SUSPENDED IN SOYMILK

2007 ◽  
Vol 31 (5) ◽  
pp. 546-558 ◽  
Author(s):  
YOKIUSHIRDHILGILMARA ESTRADA-GIRÓN ◽  
JOSÉ A. GUERRERO-BELTRÁN ◽  
BARRY G. SWANSON ◽  
GUSTAVO V. BARBOSA-CÁNOVAS
Keyword(s):  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Geobacillus Stearothermophilus

scholarly journals Star Shaped Long Chain Branched Poly (lactic acid) Prepared by Melt Transesterification with Trimethylolpropane Triacrylate and Nano-ZnO

Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 796 ◽  
Author(s):  
Le Yang ◽  
Zaijun Yang ◽  
Feng Zhang ◽  
Lijin Xie ◽  
Zhu Luo ◽  
...  
Keyword(s):  
Lactic Acid ◽  
High Efficiency ◽  
Synergistic Effects ◽  
Transesterification Reaction ◽  
Poly Lactic Acid ◽  
Cell Diameter ◽  
Nano Zno ◽  
Melt Strength ◽  
Trimethylolpropane Triacrylate ◽  
Long Chain

Long chain branched poly (lactic acid) (LCBPLA) was prepared via transesterification between high molecular weight poly (lactic acid) (PLA) and low molar mass monomer trimethylolpropane triacrylate (TMPTA) during melt blending in the presence of zinc oxide nanoparticles (nano-ZnO) as a transesterification accelerant in a torque rheometer. Compared with the traditional processing methods, this novel way is high-efficiency, environmentally friendly, and gel-free. The results revealed that chain restructuring reactions occurred and TMPTA was grafted onto the PLA backbone. The topological structures of LCBPLA were verified and investigated in detail. It was found that the concentration of the accelerants and the sampling occasion had very important roles in the occurrence of branching structures. When the nano-ZnO dosage was 0.4 phr and PLA was sampled at the time corresponding to the reaction peak in the torque curve, PLA exhibited a star-shaped topological structure with a high branching degree which could obviously affect the melt strength, extrusion foaming performances, and crystallization behaviors. Compared with pristine PLA, LCBPLA showed a higher melt strength, smaller cell diameter, and slower crystallization speed owing to the synergistic effects of nano-ZnO and the long chain branches introduced by the transesterification reaction in the system. However, severe degradation of the LCBPLAs would take place under a mixing time that was too long and lots of short linear chains generated due to the excessive transesterification reaction, with a sharp decline in melt strength.

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.

Optical rotation of dilute aqueous xanthan solutions at elevated hydrostatic pressure

1991 ◽  
Vol 42 (7) ◽  
pp. 2063-2071 ◽  
Author(s):  
B. T. Stokke ◽  
K. D. Knudsen ◽  
O. Smidsrød ◽  
A. Elgsaeter
Keyword(s):  
Hydrostatic Pressure ◽  
Optical Rotation ◽  
Elevated Hydrostatic Pressure

Effect of dietary supplementation with powder derived from Moringa oleifera and Azadirachta indica leaves on growth and microbial load of edible crickets

2021 ◽  
pp. 1-14
Author(s):  
J. Ng’ang’a ◽  
S. Imathiu ◽  
F. Fombong ◽  
J. Vanden Broeck ◽  
J. Kinyuru
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Azadirachta Indica ◽  
Moringa Oleifera ◽  
Antibacterial Properties ◽  
Acheta Domesticus ◽  
The Body ◽  
Microbial Load ◽  
Field Cricket ◽  
Bacterial Endospores

Cricket farming has shown its potential to address food and nutrition insecurity in parts of the world. However, one of the remaining challenges limiting mass production of edible insects is the affordability of feeds. One possible way to address this issue would be to explore the use of traditional plants such as Moringa oleifera leaf (MOL) and Azadirachta indica leaf (AIL) that are locally available, are protein-rich and possesses some antibacterial properties in insect feed formulation. In this regard, a study was conducted to evaluate the effect of supplementation of MOL (5 or 10%) and AIL (5 or 10%) powder in the commercially used starter chicken feed on growth and microbial load of house cricket (Acheta domesticus) and field cricket (Gryllus bimaculatus). After feeding for four weeks, the supplemented feeds with 10% MOL or 10% AIL in A. domesticus and G. bimaculatus significantly decreased (P<0.05) the body weights. Also, supplementation with MOL (5 or 10%) and AIL (5 or 10%) increased the mortality in both cricket species. Although high counts of total aerobic, Enterobacteriaceae, lactic acid bacteria, bacterial endospores, yeasts and moulds were observed, significantly lower counts (P<0.05) of lactic acid bacteria and bacterial endospores were observed in treatments containing MOL (5 or 10%) and 10% AIL in both cricket species. After processing (toasting and boiling), significant reductions (P<0.001) of all vegetative microbial cells were observed but bacterial endospores were not completely eliminated. Thus, during production and processing of insects and insect-derived products, bacterial endospores would require special attention. Salmonella and Escherichia coli were not detected in processed crickets’ samples. In conclusion, supplementation with 5% MOL or 5% AIL can produce crickets with similar body weight as control feed. Mortality increased significantly when feeds were supplemented with either MOL or AIL powder. Supplementation with MOL and AIL powders significantly reduced the cell numbers for some bacterial groups in both cricket species.

Enhanced properties of poly(lactic acid) by concurrent addition of organo-modified Mg-Al layered double hydroxide (LDH) and triethyl citrate

2019 ◽  
pp. 089270571986827 ◽  
Author(s):  
Mehrnoush Monshizadeh ◽  
Sajad Seifi ◽  
Iman Hejazi ◽  
Javad Seyfi ◽  
Hossein Ali Khonakdar
Keyword(s):  
Lactic Acid ◽  
Layered Double Hydroxide ◽  
Food Packaging ◽  
Synergistic Effects ◽  
Poly Lactic Acid ◽  
Solution Casting ◽  
Scanning Calorimetry ◽  
Concurrent Use ◽  
Triethyl Citrate ◽  
Double Hydroxide

Synergistic effects of organo-modified Mg-Al layered double hydroxide (LDH) and triethyl citrate (TEC) on the properties of poly(lactic acid) (PLA) were demonstrated. PLA/LDH nanocomposites in the absence and presence of TEC were fabricated via solution casting technique. Morphological analysis revealed that as the LDH concentration increases, the number of aggregations is also increased; however, introduction of TEC considerably enhanced the dispersion quality of LDHs. Differential scanning calorimetry results showed that the addition of LDH and TEC had no significant influence on the crystallinity of nanocomposites obtained from solution casting. In contrast, once the samples were cooled from melt, the concurrent use of LDH and TEC led to a dramatic enhancement in the crystallinity of PLA ( X c = 55.5%). Moreover, the LDH nanoparticles counterbalanced the adverse effects of plasticization by TEC leading to enhanced toughness of the final nanocomposites. LDH had also a positive influence on thermal stability of PLA, indicating the heat-insulating role of LDH particles. In conclusion, the concurrent use of LDH and TEC could extend the applicability of PLA especially in food packaging applications.

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