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Inactivation of Escherichia coli O157:H7 and Listeria monocytogenes inoculated on raw salmon fillets by pulsed UV‐light treatment
Author(s) -
Ozer Nil P.,
Demirci Ali
Publication year - 2006
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.2005.01071.x
Subject(s) - listeria monocytogenes , fillet (mechanics) , escherichia coli , fish fillet , petri dish , inoculation , food science , listeria , sterilization (economics) , chemistry , microbiology and biotechnology , biology , fish <actinopterygii> , materials science , fishery , horticulture , bacteria , biochemistry , genetics , gene , monetary economics , composite material , foreign exchange market , economics , foreign exchange
Summary The efficacy of pulsed UV‐light to inactivate of Escherichia coli O157:H7 and Listeria monocytogenes Scott A on salmon fillets was investigated in this study by evaluating the effects of treatment times and distance from the UV strobe. The sterilization system generated 5.6 J cm −2 per pulse at the lamp surface for an input voltage of 3800 V and three pulses per second. Skin or muscle side inoculated salmon fillet (8 cm × 1.5 cm) in a Petri dish was placed on shelf at three different distances from the UV strobe; 3, 5, and 8 cm. At each distance, the pulsed UV‐light treatment was performed for 15, 30, 45, and 60 s. For E. coli O157:H7, maximum log 10 reduction was 1.09 log 10 CFU g −1 on muscle side at 8 cm for 60‐s treatment, whereas 0.86 log 10 CFU g −1 reduction on skin at 5 cm for 30‐s treatment. For L. monocytogenes Scott A, maximum reduction was 1.02 log 10 CFU g −1 at 8 cm for 60‐s treatment on skin side, whereas 0.74 log 10 CFU g −1 reduction on muscle at 8 cm for 60‐s treatment. The fillet's surface temperature increased up to 100degrC within 60‐s treatment time. Therefore, some fish samples were overheated after 30 and 45 s at 3‐ and 5‐cm distances from light source, respectively, which resulted in visual colour and quality changes. Overall, this study demonstrated that about one log reduction (c. 90%) of E. coli O157:H7 or L. monocytogenes could be achieved at 60‐s treatment at 8 cm distance without affecting the quality.