scholarly journals PULSED ELECTRIC FIELD FOR PASTEURIZATION OF FRESH SUGARCANE JUICE

2018 ◽  
Vol 8 (1) ◽  
pp. 27-35
Author(s):  
Nguyen Duc Trung ◽  
Nguyen Ngoc Hoang ◽  
Dang Minh Hieu
Keyword(s):  
Electric Fields ◽  
Thermal Inactivation ◽  
Sugarcane Juice ◽  
Bacterial Cells ◽  
Irreversible Damage ◽  
Log Reduction ◽  
Interface Control ◽  
Microbial Density ◽  
Czapek Medium ◽  
Pass Through

Pasteurization methods using pulsed electric fields (PEFs) have proved efficient at non-thermal inactivation of microorganisms and pathogens. The methods usually use a series of high intensity, narrow band electric fields that pass through target mediums where they induce irreversible damage to cellular membranes leading to the death of microorganisms by internal content loss breakage of cell homeostasis and other effects. This research proposed a simple, lab-scale PEF pasteurization equipment that uses common output electric voltages (220V and 110V, which provide electric power of 5.5 and 2.75 kV/m, respectively) with a simple designed Human-Machine Interface control. At a voltage of 110V, the equipment was tested with non-sterilized Czapek medium which showed more than 1.42-log reduction in the microbial density at 30s of the treatment and temperature below 60 o C. A test on suspended E. coli in modified Czapek medium also indicated an inactivation of most of bacterial cells after 40s of the treatment. We then applied the equipment to pasteurize fresh sugarcane juice and, as a result, the content of native microorganisms in sugarcane juice was reduced 1.2-log cycle, compared to that of original juice before the treatment.

Combined Effect of Nisin and Pulsed Electric Fields on the Inactivation of Escherichia coli

2000 ◽  
Vol 63 (6) ◽  
pp. 741-746 ◽  
Author(s):  
MAURICIO R. TEREBIZNIK ◽  
ROSA J. JAGUS ◽  
PATRICIA CERRUTTI ◽  
MARTA S. DE HUERGO ◽  
ANA M. R. PILOSOF
Keyword(s):  
Escherichia Coli ◽  
Protective Effect ◽  
Electric Fields ◽  
High Voltage ◽  
Combined Treatment ◽  
Action Spectrum ◽  
Pulsed Electric Fields ◽  
Combined Effect ◽  
Bacterial Cells ◽  
Doehlert Design

The Doehlert design was applied in order to investigate the combined effect of nisin and high voltage pulsed electric fields (PEF) on the inactivation of Escherichia coli in simulated milk ultrafiltrate media. Nisin alone was totally inactivated by PEF, but in the presence of bacterial cells a protective effect was observed. However, the effectiveness of nisin was still decreased when bacterial cells were subjected to the combined treatment. In spite of this phenomenon, an almost additive response emerged as a consequence of the combined treatment. A 4-log cycle reduction may be accomplished with around 1,000 IU/ml (7.15 μM) of nisin and three pulses of 11.25 kV/cm or 500 IU/ml for five pulses of the same intensity. The observed efficacy arising from the combination of both treatments suggests the possibility of using PEF for improving the action spectrum of natural antimicrobials.

Determination of the Thermal Inactivation Kinetics of Listeria monocytogenes, Salmonella enterica, and Escherichia coli O157:H7 and non-O157 in Buffer and a Spinach Homogenate

2015 ◽  
Vol 78 (8) ◽  
pp. 1467-1471 ◽  
Author(s):  
EMEFA ANGELICA MONU ◽  
MALCOND VALLADARES ◽  
DORIS H. D'SOUZA ◽  
P. MICHAEL DAVIDSON
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Thermal Inactivation ◽  
Inactivation Kinetics ◽  
Mild Heat ◽  
Log Reduction ◽  
D Values ◽  
Heat Processes ◽  
Kinetics Of

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.

Behaviour of pathogenic E. coli and Salmonella enteritidis in small domestic sewage treatment apparatus (“Johkasou”)

2001 ◽  
Vol 43 (12) ◽  
pp. 191-193 ◽  
Author(s):  
M. Kaneko ◽  
T. Nambu ◽  
M. Tokoro
Keyword(s):  
Water Temperature ◽  
Salmonella Enteritidis ◽  
Sewage Treatment ◽  
Reduction Rate ◽  
Domestic Wastewater ◽  
Domestic Sewage ◽  
E Coli ◽  
Log Reduction ◽  
Sewage System ◽  
Pass Through

“Johkasou” is a small sewage treatment apparatus commonly used in Japan which can effectively treat domestic wastewater in places where a public sewage system is difficult to supply. The behaviour of enterohaemorrhagic E. coli 0157 and Salmonella enteritidis in a “Johkasou” was studied. Their reduction rates depended significantly on the water temperature in the “Johkasou” with minimal decrease in numbers at 10°C within 48 h. The reduction rates increased at 20°C and 30°C where 4 log reduction could be expected. The reduction rates were influenced by the BOD of the solutions that contained the pathogens with the lower the BOD the higher the reduction rate. The reduction rates were about the same between both pathogens. The result showed that it was necessary to disinfect the effluent as some pathogens can pass through the apparatus when some users of the apparatus excrete pathogens.

I. Environmental Contamination and Biochemical Relationships

1975 ◽  
Vol 38 (5) ◽  
pp. 285-300 ◽  
Author(s):  
A. G. HUGUNIN ◽  
R. L. BRADLEY
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Methyl Mercury ◽  
Sea Water ◽  
Inorganic Mercury ◽  
Whole Body ◽  
Irreversible Damage ◽  
Mercury Compounds ◽  
The Central Nervous System ◽  
Pass Through

Mercury is naturally concentrated in geographical belts, but geological cycling has distributed the element in all strata of the earth. Natural concentrations of mercury are approximately 100 ppb in soil, 0.06 ppb in fresh water, 0.01–0.30 ppb in sea water, and 0.003–0.009 μg/m3 in air. Concentrations vary, being highest near mineral deposits. The concentration of mercury in some areas has been significantly increased by human carelessness. An epidemic among Japanese fishing families, death of Swedish wildlife, and discovery of elevated mercury levels in American fish focused attention on this problem. The discovery that certain species are capable of methylating inorganic mercury indicates pollution with any chemical form of mercury is dangerous. Alkylmercurials are the most dangerous form of mercury in the environment. Alkylmercurials are absorbed from the gastrointestinal tract, diffuse across the blood-brain carrier, and pass through the placental membrane in significantly higher proportions than other mercury compounds. The whole body half-life of methyl mercury in humans is 76 ± 3 days compared to half-lives of 37 ± 3 days for men and 48 ± 5 days for women observed for mercuric salts. Not readily broken down, sufficient concentrations of methyl mercury can cause irreversible damage to the central nervous system. Renal damage usually results from high levels of aryl- or alkoxyalkylmercurials and inorganic mercury; however, vapors of elemented mercury can damage the central nervous system. Organic mercury compounds cause chromosome changes, but the medical implications resulting from levels of mercury in food are unknown. The concentration of mercury in red blood cells and hair is indicative of the exposure to alkylmercurials. On a group basis, blood and urine concentrations of mercury may corrrelate with recent exposure to mercury.

Thermal Inactivation of H5N2 High-Pathogenicity Avian Influenza Virus in Dried Egg White with 7.5% Moisture

2009 ◽  
Vol 72 (9) ◽  
pp. 1997-2000 ◽  
Author(s):  
COLLEEN THOMAS ◽  
DAVID E. SWAYNE
Keyword(s):  
Linear Regression ◽  
Avian Influenza ◽  
Thermal Inactivation ◽  
Systemic Disease ◽  
Egg White ◽  
Influenza Viruses ◽  
Log Reduction ◽  
Poultry Products ◽  
High Pathogenicity ◽  
D Values

High-pathogenicity avian influenza viruses (HPAIV) cause severe systemic disease with high mortality in chickens. Isolation of HPAIV from the internal contents of chicken eggs has been reported, and this is cause for concern because HPAIV can be spread by movement of poultry products during marketing and trade activity. This study presents thermal inactivation data for the HPAIV strain A/chicken/PA/1370/83 (H5N2) (PA/83) in dried egg white with a moisture content (7.5%) similar to that found in commercially available spray-dried egg white products. The 95% upper confidence limits for D-values calculated from linear regression of the survival curves at 54.4, 60.0, 65.5, and 71.1°C were 475.4, 192.2, 141.0, and 50.1 min, respectively. The line equation y = [0.05494 × °C] + 5.5693 (root mean square error = 0.0711) was obtained by linear regression of experimental D-values versus temperature. Conservative predictions based on the thermal inactivation data suggest that standard industry pasteurization protocols would be very effective for HPAIV inactivation in dried egg white. For example, these calculations predict that a 7-log reduction would take only 2.6 days at 54.4°C.

Synergistic Effects of Butyl Para-Hydroxybenzoate and Mild Heating on Foodborne Pathogenic Bacteria

2020 ◽  
Author(s):  
Zhujun Gao ◽  
Qiao Ding ◽  
Chongtao Ge ◽  
Robert C. Baker ◽  
Rohan V. Tikekar ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
Thermal Inactivation ◽  
Heating Temperature ◽  
Synergistic Effects ◽  
Brain Heart Infusion ◽  
Similar Treatment ◽  
Log Reduction ◽  
Synergistic Enhancement ◽  
Foodborne Pathogenic Bacteria

ABSTRACT While high temperature heat treatments can efficiently reduce pathogen levels, they also affect the quality and nutritional profile of foods, as well as increase the cost of processing. The food additive butyl para-hydroxybenzoate (BPB) was investigated for its potential to synergistically enhance the thermal inactivation at mild heating temperatures (54 – 58 ºC). Four foodborne pathogenic bacteria, Cronobacter sakazakii , Salmonella enterica serotype Typhimurium, attenuated Escherichia coli O157:H7 and Listeria monocytogenes, were cultured to early stationary phase and then subjected to mild heating in a model food matrix (Brain Heart Infusion) containing low levels BPB (≤ 125 ppm). The heating temperature used with each bacterium was selected based on the temperature that would yield an approximate 1 – 2 log reduction over 15 min heating in BHI without BPB using a submerged coil apparatus. The inclusion of BPB at concentrations ≤ 125 ppm resulted in significant enhancement of thermal inactivation, achieving 5 – > 6 log reductions of the Gram-negative strains and D-values of < 100 sec. Listeria monocytogenes achieved at 3 – 4 log reduction with a similar treatment. No significant inactivation was noted in the absence of the mild heating for the same time period. This study provides an additional proof of concept that low temperature inactivation of foodborne pathogens can be realized by synergistic enhancement of thermal inactivation by food components that affect microbial cell membranes.

Antimicrobial Effects of Silver Nanoparticles against Bacterial Cells Adhered to Stainless Steel Surfaces

2012 ◽  
Vol 75 (4) ◽  
pp. 701-705 ◽  
Author(s):  
EMILIANE A. ARAÚJO ◽  
NÉLIO J. ANDRADE ◽  
LUIS HENRIQUE M. da SILVA ◽  
PATRÍCIA C. BERNARDES ◽  
ÁLVARO V. N. de C. TEIXEIRA ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Stainless Steel ◽  
Food Industry ◽  
Antimicrobial Activities ◽  
New Method ◽  
Resistant Bacteria ◽  
Bacterial Cells ◽  
Antimicrobial Effects ◽  
Log Reduction ◽  
Steel Surfaces

Given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. This study aimed to evaluate the antimicrobial effects of silver nanoparticles (NP) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus. The ability of these nanoparticles to remove or kill vegetative cells adhered to stainless steel surfaces was also evaluated. We observed that the NP obtained with the new method, concentrated silver nanoparticles (CNP), and silver nanoparticles with added sodium chloride (NPNaCl) had high antimicrobial activities (P < 0.05). We also verified that the most effective condition for the removal of P. aeruginosa cells on stainless steel coupons (10 by 10 mm) was immersion of the surfaces in CNP. The CNP treatment produced a 5-log reduction of the microbial population after 30 to 60 min of immersion. The CNP treatment also performed better than water and sodium carbonate, a compound commonly applied in clean-in-place procedures in the food industry, in removing adherent B. cereus cells from stainless steel cylinders. Therefore, these results suggest that NP synthesized by a new procedure may be used as antimicrobials in the food industry, for example, for the sanitization of utensils that come into contact with foods.

scholarly journals A new water-soluble bactericidal agent for the treatment of polymicrobial infections

2020 ◽  
Author(s):  
Alessandro Presentato ◽  
Elena Piacenza ◽  
Antonino Scurria ◽  
Lorenzo Albanese ◽  
Federica Zabini ◽  
...  
Keyword(s):  
Water Soluble ◽  
Hydrodynamic Cavitation ◽  
Minimal Bactericidal Concentration ◽  
Bacterial Cells ◽  
Citrus Pectin ◽  
Gram Negative ◽  
Log Reduction ◽  
Citrus Flavonoids ◽  
Polymicrobial Infections ◽  
Bactericidal Agent

Grapefruit and lemon pectin obtained from the respective waste citrus peels via hydrodynamic cavitation in water only are powerful, broad-scope antimicrobial alternatives to antibiotics against Gram-negative and -positive pathogens. Dubbed IntegroPectin, these pectic polymers functionalized with citrus flavonoids and terpenes show superior antimicrobial activity when compared to commercial citrus pectin. Similarly to commercial pectin, lemon IntegroPectin determined ca. 3 log reduction of Staphylococcus aureus cells, while an enhanced activity of commercial citrus pectin was detected in the case of Pseudomonas aeruginosa cells with a minimal bactericidal concentration (MBC) of 15 mg mL-1. Although grapefruit and lemon IntegroPectin share equal MBC in the case of P. aeruginosa cells, grapefruit IntegroPectin shows boosted activity upon exposure of S. aureus cells with a 40 mg mL-1 biopolymer concentration being sufficient to achieve complete killing of the bacterial cells. Insight on the mechanism of action of these biocompatible antimicrobials and their effect on bacterial cells, at the morphological level, were obtained indirectly through Fourier Transform Infrared spectroscopy and directly through scanning electron microscopy. In the era of antimicrobial resistance, these results are of great societal and sanitary relevance as they open new avenues to develop innovative antimicrobials for the treatment of polymicrobial infections unlikely to develop drug resistance.

scholarly journals Quantitative form and fit of N95 filtering facepiece respirators are retained and coronavirus surrogate is inactivated after heat treatments

2020 ◽  
Author(s):  
Travis Massey ◽  
Monica Borucki ◽  
Samuel Paik ◽  
Kyle Fuhrer ◽  
Mihail Bora ◽  
...  
Keyword(s):  
Thermal Inactivation ◽  
Hepatitis Virus ◽  
Filter Material ◽  
Healthcare Facilities ◽  
Emergency Situations ◽  
Log Reduction ◽  
Quantitative Form ◽  
Dry Conditions ◽  
Dry Heating ◽  
Single Use

SummaryRe-use of filtering facepiece respirators (FFRs, commonly referred to as N95s) normally meant for single use only is becoming common in healthcare facilities due to shortages caused by the COVID19 pandemic. Here we report that mouse hepatitis virus (MHV) initially seeded on FFR filter material is inactivated (6 log reduction as measured by 50% tissue culture infective dose (TCID50)) after dry heating at 75 ºC for 30 minutes. We also find that the quantitative fit of FFRs after heat treatment at this temperature, under dry conditions or at 90% relative humidity, is not affected by single or ten heating cycles. Previous studies have reported that the filtration efficiency of FFR filters is not negatively impacted by these heating conditions. These results suggest that thermal inactivation of coronaviruses is a potentially rapid and widely deployable method to re-use N95 FFRs in emergency situations where re-using FFRs is a necessity and broad-spectrum sterilization is unavailable. However, we also found that a heat source that emits radiation (e.g., an exposed heating element) results in rapid qualitative degradation of the FFR. Finally, we discuss differences in the results reported here and other recent studies investing heat as a means to recycle FFRs and suggest that overall wear time and donning/doffing cycles are important factors that need to be considered.

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