scholarly journals Conventional and Innovative Hygienization of Feedstock for Biogas Production: Resistance of Indicator Bacteria to Thermal Pasteurization, Pulsed Electric Field Treatment and Anaerobic Digestion

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1938
Author(s):  
Xiaojun Liu ◽  
Thomas Lendormi ◽  
Jean-Louis Lanoisellé
Keyword(s):  
Anaerobic Digestion ◽  
Electric Field ◽  
Biogas Production ◽  
Pulsed Electric Field ◽  
Indicator Bacteria ◽  
The European Union ◽  
E Coli ◽  
Biogas Energy ◽  
Mesophilic Digestion ◽  
Thermal Pasteurization

Animal by-products (ABP) can be valorized via anaerobic digestion (AD) for biogas energy generation. The digestate issued from AD process is usually used to fertilize farming land for agricultural activities, which may cause potential sanitary risk to the environment. The European Union (EU) requires that certain ABP be thermally pasteurized in order to minimize this sanitary risk. This process is called hygienization, which can be replaced by alternative nonthermal technologies like pulsed electric field (PEF). In the present study, Enterococcus faecalis ATCC 19433 and Escherichia coli ATCC 25922 were used as indicator bacteria. Their resistance to thermal pasteurization and PEF treatment were characterized. Results show that Ent. faecalis and E. coli are reduced by 5 log10 in less than 1 min during thermal pasteurization at 70 °C. The critical electric field strength was estimated at 18 kV∙cm−1 for Ent. faecalis and 1 kV∙cm−1 for E. coli. “G+” bacteria Ent. faecalis are generally more resistant than “G-” bacteria E. coli. AD process also plays an important role in pathogens inactivation, whose performance depends on the microorganisms considered, digestion temperature, residence time, and type of feedstock. Thermophilic digestion is usually more efficient in pathogens removal than mesophilic digestion.

Inactivation of E. coli K12 in apple juice by high voltage pulsed electric field

2003 ◽  
Vol 217 (5) ◽  
pp. 434-437 ◽  
Author(s):  
B. Sen Gupta ◽  
F. Masterson ◽  
T. R. A. Magee
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Apple Juice ◽  
Pulsed Electric Field ◽  
E Coli

Inactivation of Escherichia coli O157:H7, Listeria monocytogenes, and Lactobacillus leichmannii by Combinations of Ozone and Pulsed Electric Field

2001 ◽  
Vol 64 (6) ◽  
pp. 777-782 ◽  
Author(s):  
RAGIP UNAL ◽  
JIN-GAB KIM ◽  
AHMED E. YOUSEF
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Electric Field ◽  
Pulsed Electric Field ◽  
Bactericidal Effect ◽  
Treatment Level ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Nonthermal Processing ◽  
Lactobacillus Leichmannii

Pulsed electric field (PEF) and ozone technologies are nonthermal processing methods with potential applications in the food industry. This research was performed to explore the potential synergy between ozone and PEF treatments against selected foodborne bacteria. Cells of Lactobacillus leichmannii ATCC 4797, Escherichia coli O157:H7 ATCC 35150, and Listeria monocytogenes Scott A were suspended in 0.1% NaCl and treated with ozone, PEF, and ozone plus PEF. Cells were treated with 0.25 to 1.00 μg of ozone per ml of cell suspension, PEF at 10 to 30 kV/cm, and selected combinations of ozone and PEF. Synergy between ozone and PEF varied with the treatment level and the bacterium treated. L. leichmannii treated with PEF (20 kV/cm) after exposure to 0.75 and 1.00 μg/ml of ozone was inactivated by 7.1 and 7.2 log10 CFU/ml, respectively; however, ozone at 0.75 and 1.00 μg/ml and PEF at 20 kV/cm inactivated 2.2, 3.6, and 1.3 log10 CFU/ml, respectively. Similarly, ozone at 0.5 and 0.75 μg/ml inactivated 0.5 and 1.8 log10 CFU/ml of E. coli, PEF at 15 kV/cm inactivated 1.8 log10 CFU/ml, and ozone at 0.5 and 0.75 μg/ml followed by PEF (15 kV/cm) inactivated 2.9 and 3.6 log10 CFU/ml, respectively. Populations of L. monocytogenes decreased 0.1, 0.5, 3.0, 3.9, and 0.8 log10 CFU/ml when treated with 0.25, 0.5, 0.75, and 1.0 μg/ml of ozone and PEF (15 kV/cm), respectively; however, when the bacterium was treated with 15 kV/cm, after exposure to 0.25, 0.5, and 0.75 μg/ml of ozone, 1.7, 2.0, and 3.9 log10 CFU/ml were killed, respectively. In conclusion, exposure of L. leichmannii, E. coli, and L. monocytogenes to ozone followed by the PEF treatment showed a synergistic bactericidal effect. This synergy was most apparent with mild doses of ozone against L. leichmannii.

The contribution of thermophilic anaerobic digestion to the stable operation of wastewater sludge treatment

2002 ◽  
Vol 46 (4-5) ◽  
pp. 447-453 ◽  
Author(s):  
J. Zábranská ◽  
M. Dohányos ◽  
P. Jeníček ◽  
P. Zaplatílková ◽  
J. Kutil
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Removal Rate ◽  
Wastewater Sludge ◽  
Anaerobic Sludge ◽  
Stable Operation ◽  
Sludge Treatment ◽  
Thermophilic Anaerobic Digestion ◽  
Mesophilic Digestion ◽  
Pathogens Removal

Thermophilic anaerobic digestion of sewage sludge has been successfully operated in full-scale tanks almost three years. The higher loading capacity and specific biogas production rate in comparison with mesophilic digestion was proved. Thermophilic anaerobic sludge is also more resistant against foaming problems. Biogas from thermophilic tanks contains less hydrogen sulphide and other malodorous substances. Pathogens removal rate is apparently more efficient in the thermophilic process.

Hygienization of sludge through anaerobic digestion at 35, 55 and 60 °C

2013 ◽  
Vol 68 (10) ◽  
pp. 2234-2239 ◽  
Author(s):  
H. Kjerstadius ◽  
J. la Cour Jansen ◽  
J. De Vrieze ◽  
S. Haghighatafshar ◽  
Å. Davidsson
Keyword(s):  
Escherichia Coli ◽  
European Union ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
The European Union ◽  
Good Reduction ◽  
Process Stability ◽  
E Coli ◽  
Concentration Limits ◽  
The Eu

Legislation in Sweden and the European Union concerning the use of sewage sludge in agriculture is under revision and future concentration limits for pathogens in treated sludge are likely to be expected. The aim of this study was to evaluate the hygienization of Salmonella, Escherichia coli, Enterococcus and Clostridium perfringens through continuous anaerobic digestion at 35, 55 or 60 °C, as well as to investigate process stability and methane production at 60 °C. The results indicated that digestion at 55 or 60 °C with a minimum exposure time of 2 h resulted in good reduction of Salmonella, E. coli and Enterococcus and that anaerobic digestion could thus be used to reach the concentration limits suggested for the EU, as well as Sweden. Furthermore, stable continuous anaerobic digestion of sludge was achieved at 60 °C, albeit with 10% less methane production compared to digestion at 35 and 55 °C.

scholarly journals Microbial analysis and virulence genes detection of milk preserved using heat-assisted pulsed electric field

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Suci Yuliangsih ◽  
Diana Elizabeth Waturangi ◽  
Yogiara
Keyword(s):  
Electric Field ◽  
Virulence Genes ◽  
Pulsed Electric Field ◽  
Raw Milk ◽  
Chain Reaction ◽  
Log Reduction ◽  
Milk Samples ◽  
Microbial Analysis ◽  
Polymerase Chain ◽  
Thermal Pasteurization

Abstract Objective Microbial analysis in milk preserved using heat-assisted Pulsed Electric Field (PEF) need to be assessed. In this study we analyze the microbial quality and virulence-associated genes in milk samples preserved using heat-assisted PEF from several producers in Indonesia. Results Milk samples were collected consisting of raw milk, milks taken after the heating, PEF, mixing, cooling, and packaging. Microbiological and Polymerase Chain Reaction (PCR) detection for virulence genes were performed. Heat-assisted PEF treatment gave 2.7–7.47 log reduction for TPC; 1.6–2.56 log reduction for MPN number; 3.13–6.48 log reduction for S. aureus; and for B. cereus there was an increase of 0.76 log and a reduction of 0.46 log. While milk samples from thermal pasteurization gave log reduction numbers of TPC, MPN, and S. aureus respectively 5.28; 2.56; and 4.73, for B. cereus was increasing 2.4 log. Producer C performed the best results with significant reduction compared with others (p < 0.005). There were no colonies of L. monocytogenes found in all of the samples. PCR results showed that milk samples possessed virulence genes 17.5% (10/57) of invA genes, 54.4% (31/57) of nheA genes, 68.4% (39/57) of cytK genes, 38.6% (22/57) of nuc genes, 63.2% (36/57) of ileS genes, while hly and actA genes were not detected.

Inactivation of E. Coli affected by medium conductivity in pulsed electric field

2013 ◽  
Author(s):  
Tanya Kirilova Gachovska ◽  
Jeyamkondan Subbiah ◽  
Harshavardhan Thippareddi ◽  
David Marx ◽  
Frazer Williams
Keyword(s):  
Electric Field ◽  
Pulsed Electric Field ◽  
E Coli ◽  
Medium Conductivity
Sign in / Sign up

Export Citation Format

Share Document