61C-24 |
Effect of nisin combined with EDTA and hydrogen peroxide on Salmonellla Enteritidis in liquid whole egg |
G. C. GÜRAKAN, Department of Food Engineering, Middle East Technical University, Ankara, 06531, Turkey and H. Duru, Department of Biotechnology, Middle East Technical University, Ankara, 06531, Turkey. Nisin exhibits an inhibitory effect on gram-negative bacteria when it is combined with chelating agent. Hydrogen peroxide is a common food preservative used in raw liquid eggs. In this study, the effect of nisin with combination of chelating agent, EDTA and the effect of hydrogen peroxide on Salmonella Enteritidis in liquid whole egg were investigated. Our objective was to test different concentrations and combinations of nisin and EDTA and different concentrations of hydrogen peroxide. The concentrations applied were 20mM EDTA and 50 µg/ml nisin; 50 mM EDTA and 50 µg/ml nisin; and, 50 mM EDTA and 250 µg/ml nisin. Different concentrations of (0.1, 0.5 and 1%) hydrogen peroxide were used as an antimicrobial agent in liquid whole egg. The inhibitory activity of hydrogen peroxide at refrigeration and room temperatures were also compared. Results indicated that nisin in combination with EDTA had no significant bactericidal activity, but it showed bacteriostatic effect. The most effective reduction obtained in population of Salmonella Enteritidis in liquid whole egg was approximately 1.5 log cycle when 50 mM EDTA and 250 µg/ml (104 IU) nisin were added in liquid whole egg at 20oC. All concentrations of hydrogen peroxide showed similar effect; the most effective reduction obtained was 3.38 log cycle with 1% of hydrogen peroxide at 7oC. Hydrogen peroxide had significant bactericidal effect on Salmonella Enteritidis in liquid whole egg both at refrigeration and room temperatures. Hydrogen peroxide was more effective at refrigeration temperature than room temperature. According to these results nisin and EDTA can be used as preservative to extend the shelf life of the pasteurized liquid whole egg, and hydrogen peroxide can be used as an antimicrobial agent against Salmonella Enteritidis in liquid whole egg.
Session 61C, Food Microbiology: General I
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