Efficacy of pulsed-UV light treatment inactivating Escherichia coli O157:H7 and Listeria monocytogenes on raw salmon

2004 ◽  
Author(s):  
Nil P. Ozer ◽  
Ali Demirci
2010 ◽  
Vol 100 (3) ◽  
pp. 446-451 ◽  
Author(s):  
Andreja Rajkovic ◽  
Igor Tomasevic ◽  
Nada Smigic ◽  
Mieke Uyttendaele ◽  
Radomir Radovanovic ◽  
...  

1997 ◽  
Vol 60 (9) ◽  
pp. 1046-1049 ◽  
Author(s):  
JORGE ULATE-RODRÍGUEZ ◽  
H. WILLIAM SCHAFER ◽  
EDMUND A. ZOTTOLA ◽  
P. MICHAEL DAVIDSON

The linear furanocoumarins psoralen, 5-methoxypsoralen (5-MOP), and 8-methoxypsoralen (8-MOP) were tested as antimicrobial agents against Listeria monocytogenes, Escherichia coli O157:H7 and Micrococcus luteus. The linear furanocoumarins were activated with UV light at 365 nm for 60 min. MICs of these furanocoumarins in tryptic soy broth supplemented with 0.6% yeast extract were determined at room temperature for 48 h. Psoralen was the most effective antimicrobial agent of the three studied. This compound inhibited the three test microorganisms at concentrations of 5 μg/ml or lower. Only L. monocytogenes was inhibited by 5-MOP.Concentrations of at least 10μg of 8-MOP per ml were required to inhibit the test microorganisms. Mixtures containing at least 7.5 μg of psoralen per ml inhibited the growth of the three microorganisms. In the absence of psoralen, mixtures of 5- MOP and 8-MOP were ineffective as growth inhibitors of M. luteus and E. coli O157:H7.


2017 ◽  
Vol 81 (1) ◽  
pp. 6-16 ◽  
Author(s):  
Askild L. Holck ◽  
Kristian H. Liland ◽  
Signe M. Drømtorp ◽  
Mats Carlehög ◽  
Anette McLeod

ABSTRACT Ten percent of all strong-evidence foodborne outbreaks in the European Union are caused by Salmonella related to eggs and egg products. UV light may be used to decontaminate egg surfaces and reduce the risk of human salmonellosis infections. The efficiency of continuous UV-C (254 nm) and pulsed UV light for reducing the viability of Salmonella Enteritidis, Listeria monocytogenes, and enterohemorrhagic Escherichia coli on eggs was thoroughly compared. Bacterial cells were exposed to UV-C light at fluences from 0.05 to 3.0 J/cm2 (10 mW/cm2, for 5 to 300 s) and pulsed UV light at fluences from 1.25 to 18.0 J/cm2, resulting in reductions ranging from 1.6 to 3.8 log, depending on conditions used. Using UV-C light, it was possible to achieve higher reductions at lower fluences compared with pulsed UV light. When Salmonella was stacked on a small area or shielded in feces, the pulsed UV light seemed to have a higher penetration capacity and gave higher bacterial reductions. Microscopy imaging and attempts to contaminate the interior of the eggs with Salmonella through the eggshell demonstrated that the integrity of the eggshell was maintained after UV light treatments. Only minor sensory changes were reported by panelists when the highest UV doses were used. UV-C and pulsed UV light treatments appear to be useful decontamination technologies that can be implemented in continuous processing.


2003 ◽  
Vol 66 (6) ◽  
pp. 1071-1073 ◽  
Author(s):  
BRIAN R. YAUN ◽  
SUSAN S. SUMNER ◽  
JOSEPH D. EIFERT ◽  
JOSEPH E. MARCY

To determine the efficacy of a UV light treatment at 253.7 nm (UVC light) on microbial growth, plates containing tryptic soy agar plus 50 ppm of nalidixic acid (TSAN) were inoculated with known concentrations of five-strain cocktails of Salmonella and Escherichia coli O157:H7 and subjected to different UVC treatments. The concentration of the cocktail inoculum was determined with TSAN prior to inoculation. Serial dilutions were carried out, and inoculation levels of 100 to 108 CFU/ml were tested for each pathogen. Multiple replications of doses of UV light ranging from 1.5 to 30 mW/cm2 were applied to different cocktail concentrations, and doses of >8.4 mW/cm2 resulted in a 5-log reduction of Escherichia coli O157:H7, while a 5-log reduction of Salmonella was observed with doses of >14.5 mW/cm2. Results for both organisms yielded sigmoidal inactivation curves. UVC light is effective in reducing microbial populations of pathogens on agar surfaces.


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