Inactivation of Escherichia coli by microwave induced low temperature argon plasma treatments

2002 ◽  
Vol 53 (4) ◽  
pp. 341-346 ◽  
Author(s):  
Dambadarjaa Purevdorj ◽  
Noriyuki Igura ◽  
Isao Hayakawa ◽  
Osamu Ariyada
Keyword(s):  
Escherichia Coli ◽  
Low Temperature ◽  
Argon Plasma ◽  
Plasma Treatments

Surface Properties of UHMWPE Fiber after Low Temperature Argon-Plasma Treatment

2012 ◽  
Vol 499 ◽  
pp. 90-94 ◽  
Author(s):  
Jin Yun Xu ◽  
Wen Yu Wang ◽  
Xin Jin
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Plasma Treatment ◽  
Treatment Time ◽  
Argon Plasma ◽  
Uhmwpe Fiber ◽  
Wetting Ability ◽  
Plasma Treatment Time ◽  
Uhmwpe Fibers ◽  
Ultra High Molecular Weight

To improve the adhesion between ultra-high-molecular-weight polyethylene (UHMWPE) fibers and matrix, the UHMWPE fibers were treated by low temperature argon-plasma. The effects of argon-plasma treatment on the properties of UHMWPE have been investigated. The roughness and wetting ability were all found to increase significantly after modifications. The tensile strength of UHMWE fibers were decreased with the plasma treatment time. The optimum plasma treatment is 2min.The increasing of roughness and wetting ability of UHMWPE fiber are beneficial to the improvement the adhesion between UHMWPE fiber and matrix.

Changes in Aerobic Plate and Escherichia coli–Coliform Counts and in Populations of Inoculated Foodborne Pathogens on Inshell Walnuts during Storage

2016 ◽  
Vol 79 (7) ◽  
pp. 1143-1153 ◽  
Author(s):  
JOHN C. FRELKA ◽  
GORDON R. DAVIDSON ◽  
LINDA J. HARRIS
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Relative Humidity ◽  
Low Temperature ◽  
Foodborne Pathogens ◽  
Limit Of Detection ◽  
Sampling Time ◽  
E Coli ◽  
Plate Counts ◽  
Forced Air

ABSTRACT After harvest, inshell walnuts are dried using low-temperature forced air and are then stored in bins or silos for up to 1 year. To better understand the survival of bacteria on inshell walnuts, aerobic plate counts (APCs) and Escherichia coli–coliform counts (ECCs) were evaluated during commercial storage (10 to 12°C and 63 to 65% relative humidity) over 9 months. APCs decreased by 1.4 to 2.0 log CFU per nut during the first 5 months of storage, and ECCs decreased by 1.3 to 2.2 log CFU per nut in the first month of storage. Through the remaining 4 to 8 months of storage, APCs and ECCs remained unchanged (P > 0.05) or decreased by <0.15 log CFU per nut per month. Similar trends were observed on kernels extracted from the inshell walnuts. APCs and ECCs were consistently and often significantly higher on kernels extracted from visibly broken inshell walnuts than on kernels extracted from visibly intact inshell walnuts. Parameters measured in this study were used to determine the survival of five-strain cocktails of E. coli O157:H7, Listeria monocytogenes, and Salmonella inoculated onto freshly hulled inshell walnuts (~8 log CFU/g) after simulated commercial drying (10 to 12 h; 40°C) and simulated commercial storage (12 months at 10°C and 65% relative humidity). Populations declined by 2.86, 5.01, and 4.40 log CFU per nut for E. coli O157:H7, L. monocytogenes, and Salmonella, respectively, after drying and during the first 8 days of storage. Salmonella populations changed at a rate of −0.33 log CFU per nut per month between days 8 and 360, to final levels of 2.83 ± 0.79 log CFU per nut. E. coli and L. monocytogenes populations changed by −0.17 log CFU per nut per month and −0.26 log CFU per nut per month between days 8 and 360, respectively. For some samples, E. coli or L. monocytogenes populations were below the limit of detection by plating (0.60 log CFU per nut) by day 183 or 148, respectively; at least one of the six samples was positive at each subsequent sampling time by either plating or by enrichment.

scholarly journals Induction of Viable but Nonculturable Escherichia coli O157:H7 in the Phyllosphere of Lettuce: a Food Safety Risk Factor

2011 ◽  
Vol 77 (23) ◽  
pp. 8295-8302 ◽  
Author(s):  
Laura-Dorina Dinu ◽  
Susan Bach
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Low Temperature ◽  
Cell Density ◽  
Prolonged Storage ◽  
Potential Hazard ◽  
Vbnc State ◽  
Viable But Nonculturable ◽  
Content Type ◽  
E Coli

ABSTRACTEscherichia coliO157:H7 continues to be an important human pathogen and has been increasingly linked to food-borne illness associated with fresh produce, particularly leafy greens. The aim of this work was to investigate the fate ofE. coliO157:H7 on the phyllosphere of lettuce under low temperature and to evaluate the potential hazard of viable but nonculturable (VBNC) cells induced under such stressful conditions. First, we studied the survival of six bacterial strains following prolonged storage in water at low temperature (4°C) and selected two strains with different nonculturable responses for the construction ofE. coliO157:H7 Tn7gfptransformants in order to quantitatively assess the occurrence of human pathogens on the plant surface. Under a suboptimal growth temperature (16°C), bothE. coliO157:H7 strains maintained culturability on lettuce leaves, but under more stressful conditions (8°C), the bacterial populations evolved toward the VBNC state. The strain-dependent nonculturable response was more evident in the experiments with different inoculum doses (109and 106E. coliO157:H7 bacteria per g of leaf) when strain BRMSID 188 lost culturability after 15 days and strain ATCC 43895 lost culturability within 7 days, regardless of the inoculum dose. However, the number of cells entering the VBNC state in high-cell-density inoculum (approximately 55%) was lower than in low-cell-density inoculum (approximately 70%). We recorded the presence of verotoxin for 3 days in samples that contained a VBNC population of 4 to 5 log10cells but did not detect culturable cells. These findings indicate thatE. coliO157:H7 VBNC cells are induced on lettuce plants, and this may have implications regarding food safety.

Sterilization of Sutures by Low Temperature Argon Plasma

1998 ◽  
Vol 13 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Fatma Ayhan ◽  
Hakan Ayhan ◽  
Erhan Piskin
Keyword(s):  
Low Temperature ◽  
Argon Plasma

scholarly journals Assessment of quality and safety of pork treated with low-temperature atmospheric-pressure plasma

2021 ◽  
Vol 6 (1) ◽  
pp. 78-86
Author(s):  
N. Yu. Moskalenko ◽  
O. A. Kudryashova ◽  
L. S. Kudryashov ◽  
S. L. Tikhonov ◽  
N. V. Tikhonova ◽  
...  
Keyword(s):  
Low Temperature ◽  
Atmospheric Pressure ◽  
Cold Treatment ◽  
Meat Product ◽  
Argon Plasma ◽  
Atmospheric Pressure Plasma ◽  
Weight Fraction ◽  
Microbial Inactivation ◽  
Temperature Plasma ◽  
Pressure Plasma

It is known that processing methods ensuring partial or full microbial inactivation are quite limited. Therefore, it is of great interest to develop technique and technologies allowing the effective action on microorganisms without a significant influence on product properties. The use of cold plasma can be one of the promising methods of meat product treatment by cold sterilization. The present work examines a possibility of chilled meat treatment with low-temperature atmospheric-pressure plasma to increase its stability to microbial spoilage and extend shelf life. To obtain low temperature plasma, the equipment developed by the designing department “Plasmamed” was used. Chilled meat was treated with low-temperature atmospheric-pressure argon plasma for 5, 10, 20 and 30 min. Samples were stored at a temperature of 2–4 °C for 10 days. Organoleptic indices, moisture weight fraction, changes in pH and water activity were analyzed before treatment and during storage. Sanitary microbiological analyses were carried out by the following indicators: quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM), the presence and quantity of coliforms, Salmonella, Escherichia coli, Listeria monocytogenes, Proteus. It was shown that meat cold treatment with argon plasma inhibited the development of mesophilic microorganisms. The colony forming units detected in the samples after ten days of storage were determined by the duration of exposure to plasma. It was proved that meat treatment for 15 and 30 min had the bactericidal effect and facilitated an improvement in meat color during storage. The organoleptic indices of the samples treated with plasma corresponded to the requirements of standards and approved consumer characteristics.

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