Screening for Listeria monocytogenes Surrogate Strains Applicable to Food Processing by Ultrahigh Pressure and Pulsed Electric Field

2011 ◽  
Vol 74 (10) ◽  
pp. 1655-1661 ◽  
Author(s):  
JOY G. WAITE-CUSIC ◽  
BEATRICE H. S. DIONO ◽  
AHMED E. YOUSEF
Keyword(s):  
Listeria Monocytogenes ◽  
Electric Field ◽  
Pulsed Electric Field ◽  
Ultrahigh Pressure ◽  
Processing Technologies ◽  
Process Validation ◽  
Sweet Whey ◽  
Candidate Target ◽  
Process Combination

Ultrahigh pressure (UHP) and pulsed electric field (PEF) are emerging processing technologies developed to enhance the safety while maintaining the fresh-like quality of food. For each food and process combination, a pathogen of concern (i.e., target pathogen) must be determined, and a low-risk microorganism that serves as the pathogen surrogate for process validation must be identified. The objective of this study was to identify a surrogate for Listeria monocytogenes for UHP and PEF process validation. Potential surrogates tested include four Lactobacillus spp., a Pediococcus sp., and a Listeria innocua strain. These were compared with nine L. monocytogenes strains, with regard to sensitivity to UHP and PEF processing. For UHP treatment, the strains were suspended in citrate-phosphate buffer (pH 7.0 or 4.5), sweet whey, or acidified whey and pressure processed at 500 MPa for 1 min. For PEF treatment, the strains were suspended in NaCl solution, acid whey, or sweet whey and processed at 25 kV/cm. The lethality of UHP or PEF treatment varied considerably, depending on medium types and pH and the treated strain. Treating the tested microorganisms with UHP inactivated 0.3 to 6.9 log CFU/ml for L. monocytogenes strains and 0.0 to 4.7 log CFU/ml for the potential surrogates. When PEF was employed, populations of tested microorganisms decreased <1.0 to 5.3 log CFU/ml. L. monocytogenes V7 and OSY-8578 were among the most resistant strains to UHP and PEF treatments, and thus are candidate target strains. Lactobacillus plantarum ATCC 8014 demonstrated similar or greater resistance compared with the target organisms; therefore, the bacterium is proposed as a surrogate of L. monocytogenes for both processes under the conditions specified in the food matrices tested in this study.

Effects of pulsed electric field on freeze-thaw quality of Atlantic salmon

2020 ◽  
Vol 65 ◽  
pp. 102454 ◽  
Author(s):  
Jiaheng Li ◽  
Jiyong Shi ◽  
Xiaowei Huang ◽  
Xiaobo Zou ◽  
Zhihua Li ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Electric Field ◽  
Pulsed Electric Field ◽  
Freeze Thaw

Inactivation of Listeria monocytogenes in Milk by Pulsed Electric Field

1998 ◽  
Vol 61 (9) ◽  
pp. 1203-1206 ◽  
Author(s):  
LAURA D. REINA ◽  
Z. TONY JIN ◽  
Q. HOWARD ZHANG ◽  
AHMED E. YOUSEF
Keyword(s):  
Listeria Monocytogenes ◽  
Field Strength ◽  
Electric Field ◽  
High Voltage ◽  
Foodborne Pathogens ◽  
Treatment Time ◽  
Skim Milk ◽  
Pulsed Electric Field ◽  
Lethal Effect ◽  
Treatment Temperature

Pasteurized whole, 2%, and skim milk were inoculated with Listeria monocytogenes Scott A and treated with high-voltage pulsed electric field (PEF). The effects of milk composition (fat content) and PEF parameters (electric field strength, treatment time, and treatment temperature) on the inactivation of the bacterium were studied. No significant differences were observed in the inactivation of L. monocytogenes Scott A in three types of milk by PEF treatment. With treatment at 25°C, 1- to 3-log reductions of L. monocytogenes were observed. PEF lethal effect was a function of field strength and treatment time. Higher field strength or longer treatment time resulted in a greater reduction of viable cells. A 4-log reduction of the bacterium was obtained by increasing the treatment temperature to 50°C. Results indicate that the use of a high-voltage PEF is a promising technology for inactivation of foodborne pathogens.

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.

Effect of repeated pulsed electric field treatment on the quality of hot-boned beef loins and topsides

Meat Science ◽  
2016 ◽  
Vol 111 ◽  
pp. 139-146 ◽  
Author(s):  
Alaa El-Din A. Bekhit ◽  
Via Suwandy ◽  
Alan Carne ◽  
Remy van de Ven ◽  
David L. Hopkins
Keyword(s):  
Electric Field ◽  
Pulsed Electric Field ◽  
Pulsed Electric Field Treatment ◽  
Electric Field Treatment

Susceptibility of Human Rotavirus to Ozone, High Pressure, and Pulsed Electric Field

2002 ◽  
Vol 65 (9) ◽  
pp. 1441-1446 ◽  
Author(s):  
M. A. KHADRE ◽  
A. E. YOUSEF
Keyword(s):  
High Pressure ◽  
Electric Field ◽  
Food Processing ◽  
Food Industry ◽  
Cytopathic Effect ◽  
Virus Titer ◽  
Pulsed Electric Field ◽  
Virus Population ◽  
Processing Technologies ◽  
Human Rotavirus

The rotavirus causes a food-transmitted gastroenteritis that affects mainly children. Currently, the food industry is interested in alternative food-processing technologies, but research on the control of food-transmitted viruses by these technologies is limited. In this study, the human rotavirus was cultured on MA104 cells, and suspensions of the virus were prepared and treated with ozone, high pressure, and pulsed electric field (PEF). Virus viability was quantified as 50% tissue culture infectious doses (TCID50) per milliliter. Ozone at 25 μg/ml decreased rotavirus infectivity by 8 to 9 log10 TCID50/ml. High pressure was extremely effective against the rotavirus; treatment with 300 MPa for 2 min at 25°C inactivated ~8 log10 TCID50/ml. A small fraction of the virus population, however, remained resistant to pressure treatments of up to 800 MPa for 10 min. Viruses surviving these extreme pressures showed a cytopathic effect different from that of the untreated viruses. The rotavirus was found to be resistant to PEF treatment at 20 to 29 kV/cm, for which no appreciable reductions in virus titer were observed.

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