Factors contributing to antilisterial effects of raw egg albumen

Sensitivity of Listeria monocytogenes strain Scott A and Brie-1 to several factors in raw egg albumen was investigated. A concentration of ca 15% of albumen in trypticase soy broth was listeristatic after 24 hr at 35 degrees C, and listericidal effects were observed at higher concentrations. Supplementation of albumen with iron or biotin did not reverse the inhibition. Preheating of albumen (50-80 degrees C) caused progressive loss of antilisterial effects. Supplmentation of broth with lysozyme (greater than 1 mg/mL) produced antilisterial effects that were enhanced at pH 9; conalbumin (greater than 6 mg/mL) suppressed cell growth, while ovomucoid (greater than 2 mg/mL) was inhibitory only at pH 9. Results inferred that antilisterial effects of albumen were caused primarily by lysozyme and were enhanced by ovomucoid, conalbumin, and alkaline pH